FISHERIES RESEARCH BOARD OF CANADA

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Material in tbJs report
is not to be quoted with·
out explicit permjaioo.
FISHERIES RESEARCH BOARD OF CANADA
BIOLOGICAL STATION
ST. ANDREWS, N.B.
ANNUAL REPORT
•
and
INVESTIGATORS' SUMMARIES
1961-62
J. L. H ART, DIR ECT O R

Restricted
Material in this report
is not to be quoted without
explicit permission.
FISHERIES RESEARCH BOARD OF CANADA
BIOLOGICAL STATION
ST. ANDREWS, N.B.
ANNUAL REPORT
and
INVESTIGATORS' SUMMARIES
1961-62
J. L. HART, DIRECTOR

REPORT FOR 1960~61 OF THE
BIOLOGICAL STATION, STG ANDREWS, N.B.
by J. L. Hart, Director
For the Maritime Provinces the Biological Station at
Sto Andrews discharges the responsibility of the Fisheries
Research BoaTd to conduct investigations of practical and
economic problems connected with marine and freshwater fisheries.
This involves widely varied approaches in different investigations,
board coverage by species and area and specialized tools.
Since problems are many and resources limited, priorities must
be established so that nothing significant is neglected and
important matters receive due attention.
Traditionally much of the research at Sto Andrews has
been directed to managing existing resources. Some application
of research results is directed through the Department of
Fisheries as for lobster. In the case of the lobster, the Station
has assumed a special role in educating fishermen in the
bases for management as it is realized that a generally unacceptable
regulation cannot be enforced. In other cases
application and co-ordination are promoted through committees
at various levels. Oyster results are reviewed at a Section
meeting of the Federal Provincial Atlantic Fisheries Committee
where Department, research and industry people meet. General
shellfish problems, including those involving public health, are
dealt with in an interdepartmental committee for which the Station
is supplying the chairman. Salmon research results and management
problems are considered together at a federal provincial group
meeting as a basis for recommending further study and action.
Conservation measures for groundfish operations in international
waters are recommended by the International Commission for the
Northwest Atlantic Fisherieso This Commission, representing
thirteen nations, recommends the research necessary as a basis for
international conservation agreements. The research is carried
out by national research agencies including the Board's Stations
at St. Andrews and St. Johnvs.
Knowledge of fish stocks and fisheries can be applied
to increasing the efficiency of exploitation. A direct way of
doing this is by introducing proved fishing methods for use on
confirmed populations of fish. The Station has been active in
promoting small draggers, longlining, and Danish seining and
these fishing methods are now well established in our region.
Already, all or most of the promising fishing methods used in
ether regions have been tried. In addition, some local innovations
and adaptations have proved useful. The larger mesh size
in groundfish otter trawls and the larger ring size in scallop
drags proposed first as conservation measures improved efficiency
of operations. More recently mechanized clam digging was adapted
to Maritimes needs by the Station. The equipment not only provides
substantially improved returns for the fishermen's efforts but
also has conservational advantages. Predictions of the 'why, wh~n,

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and where' of fish concentrations provide usefulinformat;f..cn to
the fish;lng industry. Future work in increasing efficiency of
fishing practices is planned .to relate behaviour of fish under
different circumstances and the performance of gear.
In the past the Station has explored unused resources
and this kind of work will be continued and intensified. Development
of the winter flounder fishery in Nova Scotia was fostered
by the Board. New scallop grounds have been located and assessed.
Interest of a less positive kind is now being taken in the
growing pollock fishery at the mouth of the Bay of Fundy through
studies of the fishery and the biology of the fish. Surveys in
offshore waters gave promising indications of large deep sea
pelagic fishes, such as sharks and tunas, and it is proposed to
continue observations on them actively. Attempts to introduce
European oysters met with indifferent success but could well be
renewed with hardier strains or more cold-tolerant species.
The well being of fish populations depends upon the
water environments, their temperatures, movements, and chemical
and biological contents., Only if environmental effects are
understood can changes in fish stocks be properly interpreted.
Both long-term trends and shorter variations in water conditions
in the sea are studied in co-operation with the Board 1 s Atlantic
Oceanographic Group and with other agencies. Trends in groundfish
populations, movements of herring, production of lobsters and of
poisonous plankton are all considered in relation to natural
oceanographic conditions. In estuarial and fresh waters, the
results of human activity for good or ill have importance. The
effects of impoundments on salmon and trout stocks, the effects of
insecticides and of industrial and minin·g pollution on salmon,
and the results of fertilizing water to .increase trout production
are some of the subjects currently under investigation. More
positive is a study of the feasibility of increasing the yield of
adult salmon by controlling the action of predatory birds on
smelt stocks.
In the work at St. Andrews, environment for lobsters
is studied in rather a special sense. Most lobsters are held and
shipped alive. Much research has been directed to the cond.itions
for survival in both water and air. The results of these studies
have been widely applied in industry. The industry is greatly
concerned by occasional outbreaks of epidemic disease in lobster
holding units and this is the subject of study.
An important objective in producing fish is control of
stock and growing conditions so as to escape the current hunting
economy and to operate on a farming basis. Starts in this
direction have been made for oysters and the anadromous fishes.
In each, cultivation for part of the life history has been found
possible, and in each the animals are allowed to live under
natural conditions during part of their lives. For each species
and under all kinds of conditions more research is necessary to

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assure successful culture. Even more important there must be
careful assessment of the practical value of each costly modification
of natureo
The administrative and laboratory headquarters for
research in fisheries biology in the Maritimes is at St. Andrews,
N.B. Work there is su~plemented by field stations when research
with local significance is required or fie~d data must be
collected. Oyster rese~rch is centred at Ellerslie, P.E.I.
In addition, field observations are made at the Fisheries
Department's demonstratton oyster farms at Orangedale and
Malagash, N.S., and Shippegan, N.B. A quahaug mortality at
Negtiac', N .B., was given special study. A statistical office in
Halifax, N.S., makes preliminary tabulations of records for
groundfish and other species supplied by port contact technicians
at Sydney, Lunenburg, and Yarmouth, N.S. Yarmouth is also a
centre for work on herring in southwest Nov~ Scotia. Year-round
field bases for salmon work were maintained at Chatham, N.B.,
for Miramichi River studies and at Elgin, N.B., for work on the
Pollett River. Observations during the whole open water season
are made in connection with trout work at Ellerslie Brook, P.E.I.,
and Crecy Lake, N .B. In additio_n special seasonal observations
on trout were made in Stevenson's and Simpson's Ponds, and at
Cains River, P.E.I. Seasonal bases were set up for groundfish
studies at Caraquet, N.B., and for lobsters at Miminegash, P.E.I.,
and at Gabarus, Fourchu, and Port Maitland, ~.s. Methods of
handling live lobsters an4 cod were observed in a special trip to
Newfoundland.
Observations at sea are essential to fisheries research.
At present the Station operates four vessels. The Mallotus (50
feet) and Clupea H. (30 fe~t) are maintained as duty boats at
St. Andrews and Ellerslie respectively. The Pandalus II ('50 feet)
utakes systematic surveys of the abundance of lobster larvae and
young in Northumberland Strait in the area between Miminegash,
P.E.I., and Richibucto, N.B. The Harengus (84 feet} serves
several investigations from the Gulf of Maine ~o the Gulf of St.­
Lawrence. In addition 1to these vessels operated by the Station,
ethers are ava~lable for sp~cial cruises. The Board's A. T.
Cameron (175 feet} was diverted from the St. John's Station for
use from St. Andrews on two occasions. The C.N.A.V. Sackville
(210 feet) was used for oce•nographic observations. Four vessels
were chartered for specific operations. The Cape Eagle {120
feet} was used for studies--of the effect .of ring size in scallop
drags. The Gloucester 27 (57 feet) was used for general exploration
for scallops in the southwen Gulf of St. Lawrence, and later
a .44-foot vessel was emplqyed for special inshore studies around
tne ~orthwest end of Prince Edward Islan~. The Roxinda Ann (62
feet) was used in pollock studies around the mouth of the Bay of
Fundy. In 1961 the 70-foot J. J. Cowie was retired from the
Board's service.

= 4 =
Acknowledgements and Liaisono The work of the St.
Andrews Station and its application depend upon co=operative
arrangements of several kindso Happy relations with fishermen
led to obtaining fishing records and tag returnso The captains
of the larger chartered vessels helped beyond the terms of their
agreements. The general public has forwarded our work by returning
cards from drift bottles set out to study ocean currentsa
Very important in the drift-bottle work is the assistance given
by the masters and office::rs of the CoP.SoSa Princess Helene and
the C.NaR. Bluenose, Abegweit, and William Carson in bottle drops.
The Sambro and Lurcher. lightships also co-operated effectively in
making daily drift~bottle releasesa Provincial governments have
provided useful assistanceo Prince Edward Island helped with
arrangements for experimental ponds~ provided a creel census taker
at Cains River 9 and gave other help. New Brunswick provided
surveys in support of construction projects and co=operated in
applying various findingso Nova Scotia through its Research
Foundation supplied a port observer for the salmon investigation
and gave sympathetic support in other ways.,
Relations ·with other stations and agencies have been
cordial and fruitful" Exchanges of visits and ideas among Board
stations and units have been prqductive" Association with the
Atlantic Oceanographic Group has. bee:n especially closeo Relations
with United States counterparts at Boothbay Harbor and Woods Hole
have been of common advantageo Data are exchanged with Sto John°s
and Woods Holeo Cdntacts wlth various branches of the Department
of Fisheries recognized the community of interests of Board and
Departmento They were most active concerning salmon, trout~
oysters, gear development, and statistics. Liaison through
committees has been referred to earliero Ideas and services are
exchanged through Departmental {oyster) interdepartmental (salmon
and shellfish) and international (ICNAF, FAO, ICES) groups and
at the Resources for Tomorrow Conferenceo The Station is grateful
for the help of Mro Phillip Goggins of the Maine Department of
Sea and Shore Fisheries for his help in the study of lobster
disease and to Dro Luigi Provasoli for his advice and media for
culturing Gonyaulaxo
The Station has provided many services as well as
received themo Some of the more demanding efforts were arranging
a training course for fishery officers, maintaining a library of
oceanographic data, and providing a stop:gap service in analysing
water from salmon rivers for heavy metals to assist the New
Brunswick Department of Minesa
The problem of communicating results is always before
the Station~s staffo This must be done for various audiences
and in different wayso Perhaps the most useful service is given
through consultation in one of several ways on special problems
and by preparing research reportso These ways of communication
are supplemented by printed scientific or trade articles and by

public addresses to live audiences, over radio, or on television.
Working through provincial development services or through
extension services of universities holds promise of effectively
reaching a wider publico
LOBSTER
Lobsters, our most valuable Atlantic inshore fisheries
resource, provide a livelihood for thousands of small-boat
fishermeno Since lobsters command high prices and are readily
, accessible, the stocks are heavily exploitedo Research to ensure
wise use of the resGurce has followed two major lines--field
studies to provide the biological basis for managing the fishery
and laboratory studies of the factors affecting the survival and
behaviour of lobsters. The latter studies have been directed
primarily to improving methods of storing and shipping live
lobsters but the results have also been useful in interpreting
.field data.
Studies of the commercial fisheryo Studies in four
fishing areas that differ markedly have been continued since 1945
(Summary Noo l)o The data include special catch and effort
statistics, measurements of sample catches 3 recaptures of tagged
lobsters and temperature recordso Numerous small boats fish at
Gabarus, NoS., where the average catch per boat in 1961 was only
1,730 pounds valued at $700. On the contiguous but more exposed
Fourchu grounds, fewer but larger boats caught 4~400 pounds of
larger, more valuable lobsters worth $2,050o At both ports a late
spring was accompanied by markedly reduced landingso At Miminegash,
P.E.I.~ a small-lobster area, the average catch per boat was 3,700
pounds valued at only $1,250o Along the exposed Port Maitland,
N.So, shore, the 6~month winter and spring season is costly to
fish but catches are high 9 averaging 8,000 pounds per boat valued
at $4, 150o
Growth and survival. To determine how fast lobsters
grow and how well they survive in nature, three large-scale
marking experiments are in progress (Summary No. 2). At Gabarus,
N.S., of 5,079 marked lobsters released in 1958, 1,179 were
recovered in 1959, 374 in 1960 and 75 in 196lo F~om 1958 to 1961,
"shorts", "canners", and "markets" grew 35, 27,and 26% in carapace
length, 149, 103, and 109% in weighto Of the lobsters released as
shorts in 1958, 90% by weight have been recaptured to the end of
196lo Since returns are almost certainly incomplete it would
appear that the present size limit in this area is -justifiedo
At Port Maitland,~.s.~ 9s041 marked lobsters were released in
the spring of 196lo Only 560 were recovered during the next
season (Dec. 9
60 to May 9
61) and very few appear to have survived
to February 1962o There is as yet no explanation for this poor
survivalo Growth per moult averaged l2o7% in carapace length
but nearly half the lobsters failed to moult during the 1960
growing season. At Miminegash, P.E.I., 8,202 marked lobsters

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were released in September and October 1961.
are expected in August 1962.
First recoveries
Larval and early bottom stages. These studies have
been conducted in Northumberland Strait annually since 1949 to
determine the apundance, growth, distribution and survival of the
early stages (Summaries Noo 3 and 4). A thorough analysis of the
accumulated data has been started to determine whether changes
in the commercial fishery can be explained or predictedo The
hatch in 1961 was about average but for the third consecutive
year fourth-stage larvae were scarceo Spring water temperatures
were low and the hatch was considerably later than usualo There
was some evidence of larval drift that corresponded in general
with movements of drift bottleso During the spring and fall,
2,436 small lobsters were caught in 301 drags of 10 minutes each.
Effect of cover on survival. Lobsters appear to be
most plentiful on rocky bottom where:they seem to spend most of
their time in burrows, emerging briefly for feeding and mating.
On soft bottom they dig and occupy saucer-shaped depressions.
Cover may be one of the most important factors affecting survival
in nature and might reduce mortality during storage. In a preliminary
test to evaluate cover, three lots of 50 one-pound
lobsters were stored in shallow wooden tanks (Summary Noo 5).
Two lots were provided with individual hollow tiles which were
occupied almost immediately. Ten per cent of the lo.bsters with
cover died in a 7-month period in contrast to 40% mortality among
the exposed lobsters. Field trials are planned for areas where
lobsters are abundant and natural cover scarce.
Survival of lobsters in air. In cool, moist air
lobsters can be stored without significant mortalities for 5 days.
Efforts to extend this storage period by flushing with oxygen, or
by increasing air pressure were unsuccessful (Summary No. 6).
Lobsters held without food for 2 to 3 weeks survived 1 to 3 days
longer in air than those recently fed.
Temperature acclimation. The lobster's survival and
behaviour both in nature and in captivity are determined in part
by its temperature acclimat6ono Experiments this summer showed
that lobsters ta~en from 10 C water require 10 days to beaome
ac8limated to 15 C and 12 days to become acclimated to 20 C or
25 C (Summary No. 7). Analysis of these data together with
results obtained previously indicates that the rate of acclimation
is determined primarily by the change in temperature rather than
the actual levelo
Dis ease. Gaffkya homari, the organism that causes
lobster blood disease, was found in mud samples from several
lobster pounds and in various blood samples. No serious
commercial losses that could be ascribed to the disease were
observed. ~obstsrs igjected w6th a suspension o~ Gaffkya and
stored at 5 , 10 , 15 , and 20 C developed the disease faster

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and died sooner at the higher temperatures (Summary Noo 8).
Lobsters given heavy injections of Gaffkya developed the disease
faster but died at the same rate as those given light injections.
Terramycin injections bad no apparent effect on the disease.
Shell disease caused some mortality among impounded lobsters.
Two and possibly three types of bacteria capable of digesting
chitin were found on the shell of an infected lobster.
OYSTER
The oyster is the only cultivated marine species in the
Maritimes. It is readily salable at high prices so that inexpensive
and effective ways of mass production cf high-quality stock are the
object of researchc In addit16n,methods'b'f"overc61Uiflg> tne_acbrersa..,~ects
of disease and environment that have plagued and are plaguing the
industry are being soughto
Oyster hatchery technigueso The most important project
in contributing to the long·-term expansion of the oyster in~ustry
is developing oyster hatchery techniqueso In 1961 for the first
time in Canada, oysters were bred in captivity and carried through
the succeeding larval stages to spatfall (Summary Noo 10). Efforts
to develop an artificial food for larvae gave promising results.
If this can be perfected it will be a long stride toward dependable
operation of commercial hatcheries. In 1962 the Department of
Fisheries plans a pilot-plant hatchery. It will be operated as a
Department-Board project to refine and demonstrate hatchery
techniques and eventually to explore the greatest potential of
hatcheries which is selective breeding of desirable strains of
oysters.
Malpegue disease field studies. In 1961 there has been
no noticeable spread of disease to unaffected areas but it is still
running its course among native oysters at Miscou, NoB., (Summary
No. 11). Disease-resistant Prince Edward Island oysters transplanted
to mainland areas to breed and restore stocks are thriving
and apparently reproducing normally o A high pr.oportion of the
spat that settled in stocked areas in 1959 is surviving,, ·apparently
resistant to diseases Prospects are bright for early recovery of
devastated areaso
!
Growth of resistant and susceptible spat. Growth in
sh~ll length and in weight of disease-resistant and disease­
·susceptible spat were compared when these animals were exposed
and when they were not exposed to disease (Summary Noo 12). When
exposed, the average growth of resistant oysters was greater than
that of susceptibles. But some susceptibles (even some of those
which eventually died of disease) grew as well as or better than
the resistants o When not exposed to. dis-ease, the susceptibles
grew vigorously. Apparently dise~se does not affect oysters
uniformly and good or poor growth is not a useful indicator o-f
disease in individual oysters.

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Oyster mortalities in Malpegue Bay. For several years
including 195B-59, there were substantial mortalities of native
oysters in central Malpeque Bay. Healthy oysters intr~auced there
in 1959 have been compared,with the natives (Summary No. 13). So
far there have been no mortalities in either st.ock but the natives
have been consistently thinner and showed large numbers of small
trematode parasites on their gills. In 1961 both stocks became
very thin and trematodes were found in both stocks. These ~ay
interf~re with feeding and by weakening the oysters may be indirectly
responsible for winter deaths. A similar condition in
Bideford Narrows has been under observation. It is important to
study these conditions because they may become more frequent as
oyster farming becomes more intense.
Oyster mortalities at Orangedale, N.S. Records for
many thousands of oysters show that annual mortalities of
Orangedale oysters have increased alarmingly from 5% in 1956 to
30% in 1961. Heaviest losses occur in spring (May-June) and late
summer (August-September). No age group is affected more than
another. The causes are obscure but are being sought. Fishermen
claim that mud-blister worms are responsible but our surveys
discount their view (Summary No. 20).
Hexa~ita culture studies. Hexamita. is a minute
protozoan that has been sl,lspected as the cause of Malpeque disease.
This year a method of growing it in pure culture was developed
(Summary No. 15). This is a major break-through and study of its
life history and the factors affecting its population growth in
cultures have been begun. Methods or·measuring protozoan abundance
in oysters are being developed.
Oyster larvae agd spatfall 1961. Spawning was late in
1961 with two major peaks in mid July and early August (Summary
No. 16). Larvae were less abundant than in any year since 1958.
Only at Ellerslie were there enough for spatfall prediction.
The gross spatfall on egg-crate filler collectors was·even lighter
than expected from the numbers of larvea seen. Following spatfall
in Bideford River, adverse water conditions produced severe
mortalities so the net catch was only modest. At Shippegan catches
were better than usual but the best sets were in Gillis Cove, Bras
d'Or Lake, N.S. Small-scale tests of the usefulness of scallop
shell strings laid on polyethylene sheeting spread on the bottom
in the intertidal zone in Bideford River took good sets. This
simple method of spat collection may have industrial possibilities.
Conway Narrows changes. Surveys of the Narrows in
1958, 1959, and:l961 show a fourfold increase in numbers of eelgrass
plants and an increase in plant size. This heavy growth
made it necessary to use hand rakes in 1961 instead of the
escalator harvester to fish bedding oysters that were'reared
there. The bottom has become softer and the shell shape of oysters
has suffered. The condition (fatness) of oysters has·decreased too.
At first it was thought that these changes were caused by~changes
..

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in the topography of the Narrowso But aerial photographs taken
in 1935 and 1958 indicate that the area is stable. The eel-grass
changes are part of an upsurge of this plant everywhere in the
Maritimes. The softening of the bottom seems to have been caused
by an accumulation of oyster faeces. The poor condition is
attribu~ed to food scarcity aggravated by over-stocking of the
~rea. Ways of combating these problems are being sought.
South Harbour, N.S., oyster observationso In 1960
South Harbour oysters became very thin in October when heavy
rains depressed the salinity. They held poorly in storageo This
year the salinity remained high and there was a heavy mortality
(30%) on the beds. Dead oysters show,ed no signs of disease but
were very thin. This appears to be due to poor feeding conditions.
Fertilization might improve conditions in this naturally·heavystocked
area and in certain others that are poor producers of
oyster foodo
Hrdrographid.and meteorological records at Ellerslie.
Thirty years' records of water temperature and salinity, rainfall,
sunshine, etc., have now been assembled by the Ellerslie Sub­
Station. An analysis of these is now under way in search of
combinations of factors which affect oyster behaviouro The hope
is to develop a system of forecasting good and poor years for
spatfall, growth, fatness~ etc. Evidence is accumulating on the
importance of winter conditions to oysters and a program of winter
observations is being exp~nded. Last winter (1961-62) water
temperatures were below 3 C (minimum temperature for oyster feeding)
for 170 days. This is 30 to 40 days longer than normal.
CLAMS AND QUAHAUGS
Clam stocks in the Maritimes have been low in recent
years partly from wasteful methods of harvesting. To aid industry,
harvesters that are less damaging and more efficient (Summary No.
21) have been developed. Quahaug stocks are low, too, but can be
increased by management and semi-culture. Disease has inter€ered
with development of semi-culture so it has been studied in the
hope of overcoming it. Paralytic shellfish poisoning is a
seasonal public health problem. It is under study to improve
control and still permit safe use of the shellfish.
Hydraulic clam rake. Development of the hydraulic
rake was undertaken in 1960 with assistance from the Industrial
Development Service of the Department of Fisheries. ·It was
continued this year at Fisheries Research Board expense. ln 1961
modifications in design increased efficiency and facilitated
handling. In sandy soils and with short nozzles the·rake now
takes over 90% of the marketable clams in its path and destroys
less than 5'% of the small clams left behind in the soil. The
conventional short-handled clam hack takes 60~ of marketable
clams from the ground turned and destroys 50% of the small clams
that are left behind. It seems that sustained annual yields from

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our clam grounds can be increased if clam hacks are replaced
by hydraulic rakes.
Quabaug mortalities at Neguac, N.B. Native Hay Island
quahaugs have shown heavy losses in recent years and mass
quantities of small quahaugs have been transferred (semi-culture)
from nearby Malpec to Hay Island to restore its stocks. This
year there are indications that both the transferred and the
native Hay Island stocks are diseased. Several possible pathogens
have been isolated (Summary No. 22).
Paralytic shellfish poisoning. Poisoning from bivalve
molluscan shellfish is a serious public health problem in parts
of the Bay of Fundy and estuary of the St. Lawrence as well as in
British Columbia. With help from the Department of Fisheries and
the Department of National Health and Welfare, a more reliable
system of forecasting danger periods is being sought in order to
simplify management problems (Summary No. 23).
In 1961 it was shown that Bay of Fundy shellfish become
toxic when a microscopic plant (Gonyaulax) is abundant in the
plankton and that the plankton itself is toxic when Gonyaulax is
most abundant. Gonyaulgx has been isolated and grown in dense
pure culture. Poison has been extracted from the cultures and
non-toxic shellfish were made toxic by feeding them cultures.
The poison load, per cell, of Bay of Fundy Gonyaulax seems greater
than that of its counterpart which is responsible for the poison
problem in Pacific coastal waters.
The life history of Gonyaulax in the laboratory and in
natural waters is being studied to determine what temperature,
light and other conditions favour rapid build-up of populations.
It is hoped that this information will allow us to predict danger
periods in the Bay of Fundy region. So far we have not studied
conditions in the St. Lawrence.
SCALLOP
The Maritimes scallop fishery is in a buoyant condition.
Production reached an all-time high in 1961. Georges Bank showed
most gain but Bay of Fundy and Gulf of St. Lawrence fisheries
also improved. Life history studies are designed to discover the
causes of varying production; gear studies search for methods of
best use of stocks, and explorations attempt to help industry
realize its potential.
Larval development of scallops. Ripening adult scallops
were maintained in the ~aboratory by feeding them cultured algae
but could not be stimulated to spawn. Finally they spawned
when scallops in Passamaquoddy Bay spawned (S~ary No. 24).
Their fertilized eggs developed into larvae that grew rapidly
for 2 weeks, feeding on cultured food organism we provided.

~ ll -
Thereafter growth slackened and mortalities begano Some larvae
lived 42 days and grew to half the settlement sizeo This is the
first time sea scallop larvae have ever been culturedg Now that
they have been described, they can be recognized in plankton and
their development, behaviour, and distribution observed. Culture
work and studies of larval reactions to light and other factors
that may be important in distribution and recruitment of scallop
stocks will:be continuedo
The scallop fisheryo Scallops are our most valuable
molluscs (Summary No. 25). The 1961 harvest brought in 3.2
million dollars. Ninety-four per cent of the catch came from
Georges Bank, 5% from the Bay of Fundy, and 1% from the Gulf of
St. Lawrenceo Catches were higher in all areas than in 1960.
The gain was greatest on Georges Bank even though the abundance
was lower. The catch was high because the fleet increased from
20 to 28 boats and because all of them fished hardero Wharf
prices increased and made the Bay of Fundy and Gulf of St.
Lawrence fishing more attractiveo This and an increased
abundance of scallops in these two regions account for their
gains. The outlook for 1962 is bright in all areaso
Georges Bank studieso There are grounds for hoping
that the heavy production from Georges Bank may be maintained
and even increased by the use of "savings gear 11 which would
prevent the capture of the smallest (5 years old) scallops that
are shucked (Summary No. 26)o This possibility was explored
jointly with United States scientists on the suggestion of the
International Commission for the Northwest Atlantic Fisheries.
The work showed that size selection of scallop gear is not as
sharp as hoped" Most of the fleet use drags with 3-inch rings
and the trials showed that 4-inch rings caught fewer 4-year-old
and younger (smaller) scallops,caught the same numbers of 5-yearolds
and caught a few more of the oldest (6 years and more)o
Thus the use of 4-inch rings would have no savings effect. The
few trials with ?-inch rings were inconclusiveo It may be
necessary to design an entirely new type of dredge to get_the
savings effect required and to do this more should be known
about the behaviour of scallops in relation to gear performance.
Southern Gulf of Sto Lawrence scallop explorations.
A survey of scallop grounds in this region was financed by the
Industrial Development Service of the Department of Fisheries
(Summary Noo 27). Five of the 40 areas examined were well enough
stocked to ~ield good catcheso The purpose of the survey was to
discover an alternative occupation for Gulf groundfish fishermen
who are hard hit by waning cod stockso The wharf price for
scallops has been low in recent years becau-se of heavy Georges
Bank production but rose somewhat in 1961. If prices remain good,
scallop fishing on the better beds found in 1961 may be profitable
in l962o

- 12 -
GROUND FISH
International groundfish catches from the Northwest
Atlantic Ocean have been increasing and they are expected to
continue to increase in response to demands of a growing human
population. As landings increase the sizes of fish landed
decrease. There is also a change in species composition as
the abundance of large fish falls off and as new species are
added to landings.
Even though a dozen nations now exploit the fisheries
adjacent to the Canadian coast, Canada still takes the largest
share of the catch. It is in the national interest to participate
actively in international conservation of resources and Canada is
doing this through the International Commission for the Nort~west
Atlantic Fisheries (ICNAF). The St~ Andrews Station is doing a
large part of the international research in waters adjacent to
the Maritime Provinces (ICNAF Subarea 4). The Station also
contributes annual statistics and sampling reports and offers
scientific advice to Commissioners on anticipated changes in the
fisheries and effects of regulations in achieving better use of
these renewable resourceso
In the face of increasing compet~tion for labour and
capital for changing fish stocks, and for sales of fish (mainly
exports~, fishing practices are changing rapidly. Centralization
of fishing communities, development of larger~ mobile, flexible
fishing vessels, mechanization of fishing operations, and
introduction of new processing methods are replacing traditional
fishing practices. The Station contributes to this development
by advising industry and government of potentialities for more
efficient harvesting. Descriptions of underexploited and unexploited
resources are useful. Forecasts of concentrations of
marketable species, in time and space, are required for effective
planning. Predictions of variations in fish quality, such as
parasitization, are helpful. Investigations of normal behaviour
of fish and their reactions to stimuli provide background for
the development of more efficient fishing techniques.
During 1961 advances were made in our knowledge of
division of stocks; seasonal, annual and long-term changes in
abundance and distribution of groundfish by species and sizes;
effects of short-term changes in the physical and biological
environment; effects of increased commercial dragging; and
effects of mesh regulation. Experiments· on fish grow·th and
swimming speeds contributed to our under-standing of the relationships
of groundfish t.o the environment and to fishing.
Cod. The dominant species in the southwestern Gulf or
St. Lawrence-(ICNAF Division 4T) is cod. These cod are distinct
from those of the no·rthern Gulf of St. Lawrence (4S), the eastern
Gulf of St. Lawrence (4R) and offshore Nova Scotia banks (4V
south and 4W)(Summaries No. 30 and 31). During summer months

- 13 ~
these cod -are found in the Magdal-en Sha-llows-Chaleur Bay area.
During winter months the commercial sizes of -cod are found in
deeper water along the Laurentian Channel, and large numbers
migrate outside the Gulf to the northern part of 4Vo
Prior to 194? about 10 million codfish were landed
annually, almost exclusively by Canadian line fishermeno Since
then, dragging, mainly with small otter trawlers, has become
increasingly important in the Canadian fisheryu European
dragging, mainly with large otter trawlers, has also increased.
About half the total landings from this stock are now taken by
foreign fleets during winter months when the cod are concentrated
near the 100-fatbom depth contour off Cape Breton Island.
In 1960 total numbers landed were about 35 million cod (Summary
No. 33).
Research-vessel surveys and studies of commercial
operations show that the abundance of old cod bas declined
during this period of increased dragging. Cod are first caught
at a younger age, and with increased fishing mortality, relatively
few cod live longer than ? yearso It is predicted that the 195?
year-class will be dominant in 1962 landings (Summary Noo 35).
Average fresh-gutted weight of fish landed will continue to be
small, about 2t lb, and catch per hour dragged is expected to
be similar to that of 1961, about 500 lb for late-summer fishing
by 50-ton draggers. Total landings will depend on such factors
as availability of fish as determined by hydrographic conditions,
effect of ice conditions on winter fishing by Europeans, and
the amount of Canadian fishing effort on this population.
A 6-year study of the quantities and sizes of cod
discarded at sea by Canadian draggers bas shown a continuous
decrease from 25 to 6% by numbers and 9 to 2% by weight (Summary
No. 34). It is estimated that total numbers of cod discarded
in a dead or dying condition decreased from about ? million fish
in 1956 to about 1 million fish in 1961. More than half of this
saving has been due to conversion from 3-inch manila to 4t-inch
synthetic meshes in trawls, following adoption of ICNAF mesh
regulation in 195?" The remaining saving resulted from increased
utilization of smaller cod by industry, with a consequent decrease
in the sizes of cod culled for landing.
An ICNAF assessment of the expected effects of various
mesh sizes from 4 to 6 inches on yield shows that immediate
losses and long-term gains from adoption of larger meshes would
probably be small, with greatest benefit~ to gears other than
dragged ne-t-so The ICNAF group of population-dynamics exp-erts
is now completing the mesh-assessment program and extendin'g
studies to effects of ever increasing fishing effort (Summary
No. 3?).
Simple models describing effects of variable parameters
on stocks and landings are believed to provide inadequate

= 14 =
forecasts of changes in fishingo The effects of environment
and fishing on recruitment, growth, and mortalities are complex,
and inter-species relati9nships must be taken into account.
During recent years, 4T cod have shown low recruitment, a
temporary increase in growth rate which appeared to be caused
by available supply of herring as food~ sma~ler sizes at first
capture~ and variable but higher fishing mortalitieso Pertinent
laboratory experiments were conducted in 1961 to measure growth,
activity and respiration of different-sized cod when fed given
quantities of food in different particle sizesQ Estimate$ of
fishing and natural mortalities from tagging data were found to
be similar to those derived from age-composition and catch and
effort datao Two senior scientists are giving special attention
to the development of a more useful model for prediction of
future catch changes in fisherieso
Tentative conclusions are that annual landings from
the 4T cod population doubled in response to the development of
intensive draggingo Landings are now declining from the annual
200 million lb peak (1956 to 1959) to a new equilibrium level.
Further major changes in exploitation of this resource are
anticipated, and continued investigation is warranted.
Haddock. Good catches of haddock were made in the
Western-Emerald area of Nova Scotia banks during the winter and
early spring of 196lo Haddock were more available to the fishery
bscause they were concentrated in a smaller area of suitable 3 to
5 C temperatures, at depths of 45 to 60 fathoms (Summary No. 38).
The main year~classes in commercial landings from
this fishery were 1954 to 1956,, The strong 1952 year-class had
virtually disappeared from the fisheryo
Research-vessel surveys during the years 1958 to 1961
have shown that the 1956 and 1957 year-classes are above average.
These year-classes will maintain a good commercial fishery for
scrod haddock in l962o The success of the fishery will depend,
in part, on the effect of winter environmental conditions on
concentration and availability of haddocko
Surveys have shown poor 1958 and 1959 year-classes of
haddock o~ Nova Scotia bankso As a result, haddock landings
from this area are expected to drop by 1964o
Mesh=assessment studies indicate that the best mesh
size, 4i--inch manila, for minimum waste of unmarketable fish
and maximum sustained landings, is now in effect, and very
little change can be expected from adoption of a larger minimum
mesh size for haddock dragging.
Halibut. At the end of World War II, the St. Andrews
Station tested and demonstrated the longlining method of fishing
Atlantic halibuto Most of the halibut caught along the outer
.
~

- 15' -
edges of fishing banks in Subar-eas 3 and 4 are now landed on
the Canadian mainland (about 7 million lb in 1961). A few dory
schooners have been converted to halibut longlining, and a number
of 5'0- to 60-foot vessels have been built for aixed fishing,
including halibut longlining. The St. Andrews Station is
investigating the halibut fishery, with emphasis on determining
effects of incidental catches of small halibut on the line
fishery for large halibut.
During 1961 a documentary film of halibut longlining
was made and studies of research-vessel and commercial catches
were intensified.
., ~
In June 1961 the sizes of halibut caught by otter
trawlers were smaller on Western Barik than on St. Pierre Bank.
The halibut in longliner catches from Grand Bank were much larger
on the average than otter-trawled halibut (Summary No. 39).
American plaice. The most important species of flounder
in commercial landings is the American plaice. This species is
second to cod in dragger landings from the southwestern Gulf of
St. Lawrence. In 1961 biological studies of plaice were continued
in the southwestern Gulf of St. Lawrence (Summary No. 40).
Although good catches or IIB.rketable plaice were taken
at depths shoaler than 50 fathoms in June and August, catches
decreased at these depths in October, and by January only a few
small, immature plaice were taken with the A. T. Cameron. During
this latter season the largest numbers of commercial-size plaice
were taken at depths or 125 to 200 fathoms. Seasonal movements
are similar to, but less extensive than, those of cod.
In 1961 ICNAF recommended extension of the 4!-inch
mesh regulation for cod and haddock-dragging to flounder dragging
in order to ensure unnecessary waste of plaice and other flounders.
Pollock. Otter-trawler landings of pollock have been
becoming increasingly important in the canadian aainland groundfish
fishery. A study of distribution of pollock at the mouth
of the Bay of Fundy was continued in 1961 (Summary No. 41).
Returns from 1,000 medium and large pollock tagged off
Grand Manan and campobello Islands in the SUJlller of 1960 were
122 or 12% by September 1961. The returns show a southern
migration in autumn to the winter spawning areas of the southern
Gulf of Maine. In th• summer of 1961 a few returns wer-e -taken
from the "Western Hole" fishery bet1ft}en Browns and LaHave Banks,
but most returns came from the tagging area.
Survey catches in 1961 confirmed those of 1960 in
showing that large fish were caught in the Wolves Bank-River
area, medium fish in the Grand Manan ~rea on Yankee Bank and
Western Hole, and small f'ish off western Nova Scotia. Pollock
of similar sizes associated togetller in schools, and the size
composition of catches from the same ground did not vary with
gear fished.

- 16 -
Danish seining versus- gragging. During the years 1949
to 1951 the Sto Andrews Station tested and demonstrated the
potential for comaercial Da-nish seining in the Maritimes area.
This method or fishing has been a.dopted now at a number of
fishing pcrts·from Port Bickerton, NoS., to caraquet, NoB. It
has been found that 50- to 60-foot lcngliners can be readily
converted to Danish seiningo
In October 1961 catche$ by a commercial Danish seiner
were compared with these of a ccamercial dragger in Chaleur Bay
(Summary Nco 42)o Approximately equal weights per day were taken
by the two ve~sels, but the Danish seiner caught twice as much
plaice and half as much coda The dragger was particularly
effective fer marketable sizes ot cod and the Danish seiner for
aark:etable·sizes of plaiceo Discards of small fish and invertebrates
were lower for the Danish seinero
Research-vessel catch com arisonso Comparative fishing
by the 17 -foot A. T. cameron, -foot Harengus, and 55-foot
Mallctus provided information on conversion factors fer survey
studies and deductions about the behaviour of groundfish and gears.
(Summary Noo 43)o
On Neva Scotia banks in April, A. To cameron catches
of haddock were more than double Harengus catchesa Similar
results were observed in 1960 for lesser concentrations of
haddccko
The Harengus and Mallctus nets appeared to be most
effective for the same distance at slow speeds (below 2i knots)
fer cod, haddock, flounders and'sculpinso Fast tows caught mere
redfisho The differences probably resulted from the lifting of
the net from bottom at fast speeds, with resultant loss of bottom
species and greater catches of ·the mere pelagic redfisho The
apparent inefficiency of Harengus fast tows was more than compensated
by towing for the same time, that is for a greater
distanceo In this case relative efficiency was greatest for
haddock, and greater for cod and redfish than for flounders arid
sculpinso Mallctus catches with fast tows did not improve by
towing for the same time ever a greater distance, presumably
because of net distortiono
Swimming speed~. Maximum swimming'speeds of cod were
tested at about 1 and 10 C by placing them in a 6-fcot-long cage
tcw•d alongside the small research vessel Mallotus. Average
swimmins speeds increased with size of fish & Maximum s-peeds were
about 3t knots for 7- to 8-lb coda .. Similar speeds were observed
at high and low ~emperatures (Summary Noo 44)o
This study marks the beginning of a series of comparative
behavdcur studies en swimming speeds and reactions of fish
to stimulia It is expected that the results will be useful in
the development of more efficient fishing techniques.
..

- 17 -
liERRING (PELAGIC)
The herring and ether pelagic fishes of the Maritimes
area are little known and with the possible exception or the
"sardine" fishery in the Bay of Fundy, are under-exploited. The
pelagic species as a whole, therefore, merit careful investigation
to determine the size of the stocks and the potentials of
commercial fisherieso Even in the Bay of Fundy, where the
"sardine" fishery has continued at a high level for many years,
knowledge of the factors affecting abundance and availability
could provide a basis for more efficient use of the resource. In
1961 emphasis was again placed on herring but a watching brief was
kept for swordfish, mackerel, and tuna fisherieso Experimental
fishing indicated the potential for a commercial fishery for
mackerel sharks on Georges and Browns Bankso
Landing statisticsu Landings of all pelagic fish
species in eastern Canada in 1961 amounted to 228 million lb
with a landed value of $5,118,000o The catch was 30 million lb
less than in 1960 and 70 million lb less than the long-term
(1939-59) average landingso Catches of all species except
swordfish were below averageo The 1961 total was made up of 210
million lb of herring,l5 million lb of mackerel, 3o2 million lb
of swordfish, and Ool4 million lb of tuna (Summary No. 45).
Detailed landings of herring by types of gear in
Charlotte and Saint John Counties have been collected annually
since 1957 (Summary No. 46) .. The data for 1961 show that, while
average catches for all types of gear were smaller in 1961 than
in 1960, the proportion of the total catch taken by purse seines
has continued to increaseo
In the western Gulf of Sto Lawrence, herring landings
from 1940 to 1955 increased irregularly from about 70 to 90
million lb and then declined to about 40 million lb in 1961.
Widespread mortality in the Gulf in 195'4 and 1955 undoubtedly
contributed to this decline which varied in degree and timing.
In the Chaleur Bay fishery, the low point was in 1959 and there
was some evidence of recovery there in 1960 and 196lo
Herring age and growth studieso Studies of the biology
of herring populations in the western Gulf of Sto Lawrence
(Summary No. ~) and in the Bay of Fundy were carried en in 1961
with particular emphasis on studies of otolith characteristics
for determination of age, growing season, hat~hing season and
1st-year growtho At Caraquet and Magdalen Island ~n the Gulf of
St. Lawrence extensive mortalities of herring occurred in 1954-56
due to a fungus (Ichthyospcridium hoferi) disease epidemic.
Changes in population parameters are associated with the resultant
decrease in abundance and these changes are being followed.
Compared with results of 1946-48 investigations, mean lengths
for both spring and autumn samples of herring were nncnanged
in 1961. However, mean ages decreased by approximately 1.5 years,

- 18 ·-
suggesting an increa:Je in growth rate in'"these areas.
Following the disease epidemic, the proportions of
spring- and autumn-hatched fish in the spawning stocks changed
from predominately spring~hatched fish to approximately equal
numbers of each. In 1961 there were indications of a partial
return to the pre-disease situation.
In the Bay of Fundy biological studies were concerned
chiefly with the origin and recruitment of Charlotte County
"sardines" (Summary No. 47). Comparisons of "sardine" otoliths
with otoliths from spawning adults in Nova Scotia and on Georges
Bank show that the Charlotte County fish have a greater affinity
with Nova Scotia adults than either have with Georges Bank adults.
Age and growth studies show that there is a sudden influx of 0+
fish in the "sardine' 1 fishery during the last quarter of the year
(Summary No. 48)o Recruitment tc the fishery takes place almost
exactly a year after hatching and it is apparent that autumnhatched
fish are the main source of supply.
Studies of growth in an artificial environment showed
that on a diet of small pieces of dead herring, mean lengths of
"sardines" increased from 13.3 to 16.a em in 89 days with
temperatures ranging from 9.0 to 14.3 c (Summary No. 49).
Herring tagging. Herring tagging experiments were
continued in 1961 with 2~740 tagged fish being released--1,400
adult fish at Magdalen Island ~in the Gulf of St. Lawrence and
1,340 "sardines" in the Bay of Fundy (Summary No. 50). The
Magdalen Island tagging was done at the end of the spring fishery
and, so far, there have been no recaptures. This is probably
because there is no-herring fishery there except in the spring
but it would also indicate a lack of movement to other fishing
areas in the Gulfu Recovery of tags in Passamaquoddy Bay showed
little movement away from the tagging area. Recaptures of h'erring
tagged at Yarmouth and Sandy Cove, N.S., were all made at the
head of St. Mary Bay indicating a migration of herring to the
northeast in June.
Spawning surveys. A herring spawning survey was
carried out in southwest Nova Scotia in 1961 (Summary No. 51).
Two spawning beds were located, one of which was measured and
samples of eggs collected. The area measured occupied about
81,000 sq yd and was located about lt miles off Black Pt. near
Cap~ St. Mary in 7 to 8 fm of water. Egg deposits were up to
lt inches thicko Using fecundity values for European herring
and a 1:1 sex ratio, the spawning school consisted of 325-850
thousand individuals (75-200 tons).
Studies of herring larvae. Studies of the abundance
and distribution of herring larvae were carried out in two areas
-- Northumberland Strait in the Gulf of St. Lawrence and at the
entrance to the Bay of Fundy (Summary No. 52).
r

- 19 -
In Northumberland Strait the numbers of herring larvae
per tow taken annually between June 15 and July 15' have been
declining irregularly since 195'2 and reached ·"an all-time low in
1961. Since 1956, however, there has been some tendency towards
an increase in the numbers of larvae taken after July 15 and
this may indicate a change in herring spawning habits in the
Gulf of St. Lawrence.
In the Bay of Fundy emphasis is placed on larval
collections in St. Mary Bay in an attempt to follow the fate of
larvae produced from southwest Nova Scotia herring spawnings.
Newly-hatched larvae appeared in August, reached a peak in
abundance in September and declined in December. The collections
during the autumn of 1961 yielded only about one tenth as many
larvae as in 1960.
Experimental fishing. Three experimental fishing
cruises were carried out in 1961 in an attempt to discover concentrations
of pelagic fish (herring, mackerel, tuna, swordfish,
and sharks) that might be available for commercial exploitation.
The areas of operation included Georges Bank, Browns Ba.nk, Bay
of Fundy, Gulf of Maine, and the western edge of the Gulf Stream.
Fishing was done with mid-water trawls, bottom trawls, Japanese
tuna gear, handlines and drift gill-nets. Catches of herring
and tuna were insignificant commercially but substantial numbers
of sharks were taken. In 14 sets with Japanese longlines, 163
sharks (125 blues, 3? mackereLs, and 1 white tip) were captured.
The availability of mackerel sharks for which there is a good
market demand is particularly significant. Catches on Georges
and Browns Banks were approximately 10 mackerel sharks (average
dressed weight 1?7 lb) per 100 hooks set (Summary It?· 55).
Swordfish fishery. A small-scale study of the swordfish
fishery has been in progress since 1958. The program includes
an examination of catch and effort statistics and studies of the
size and weight composition of catches by months and by areas
(Summary No. 56).
In 1961 swordfish landings amounted to 3.2 million lb
with a landed value of 1.24 mil1ion dollars. The catch was 18%
below the 1960 catch and 5g% below the record landing of 6.? .
million lb in 1959. Landed values, however, were only 8% below
those for 1960 and only 10% below those for 1959. The decrease
in landings is attributable to bad weather and to a smaller
fishing effort resulting from the diversion of many awordfish·
vessels to a more lucrative and year-round scallop fishery on
Georges Bank.
The course of the fishery which is being followed by
log-book records kept by co-operating swordfish fishermen shows
considerable variation in the area and time of capture and
indicates a need for studies of environmental conditions that
influence the 4istribution of swordfish in the canadian Atlantic
area.

- 20-
SALMON
The Atlantic salmon investigations of the St. Andrews
Station comprise a large part of the salmon research program in
the Atlantic Provinceso They have been under continuous review
of a federal-provincial co-ordinating committee (now the
Atlantic Fisheries Committee and its advisory section and groups)
since 19499 The Quebec Government and the Sto John°s Newfoundland
Station of the Board participate in the research program. There
is close liaison with the Conservation and Development Service
of the Department of Fisheries and other groups Which-are
responsible for management of the salmon fisherieso The joint
research and management program is aimed at increasing salmon
stocks,and assuring their best use by commercial fishermen and
anglers.
Many useful investigations were carried out during the
20 years prior to 1949 and these were given full consideration
when the new program was planned. The increased effort in
research and management resulted from extreme concern expressed
by the public, mainly by the anglers 9 over a steady decline in
commercial catches since the last peak production in 1930. The
decline was taken to indicate a general lack of adequate protection
of spawning stocks for the rivers, including overfishing of stocks
in the sea and estuarial waters by commercial gearo The first
few years of investigation after 1949 9 combined with evidence from
the earlier studies, indicated that the problem of providing
adequate salmon stocks for an ever-increasing body of anglers
cannot be solved simply by reduction of illegal fishing in the
rivers and curtailment of existing commercial fisheries. Generally,
spawning stocks and production of fry appear to have been adequate
for the natural productive capacities of most Maritime rivers.
It seems necessary to find practical ways for increasing the
survival rates from fry to smelts in the rivers, and for overcoming
the harmful effects of man-made changes in the salmon1'·s
river environmenta Such changes are caused by industrial operations
like forest spraying with powerful insecticides which can
also kill fish~ installation of power dams that create large
artificial lakes and hold up fish migration, mining developments
from which inadequately treated effluents pour into salmonrearing
areas, arid deforestation that removes cover~ speeds runoff
and pollutes spawning and rearing areaso
One remedy is to rear young salmon through the early
stages under artificial conditions and re.lease them at or near
the smelt stage to go to sea. This obviates the need for normal
stream conditions for hatching and development through the
several years of fry and parr growth. Investigations associated
with hatchery and artificial rearing practices are, therefore,
an important part of the research program.
Availability of adults. Information obtained from
angling and commercial catch statistics provided by the Department

- 21 -
of Fisheries effectively senses the salmon ,situation as seen
by the fishing public, and helps to indicate where special
action is justified (Summary No. 64). In 1961 Maritime
commerqial catches totalled 1o2 million lb, 7% below the 1960
total, and the records continued a decline starting in 1959,
a predicted effect of earlier DDT sprayings IOn-survival of
young salmon in the Gulf areao Catches in the Atlantic area,
where no spraying has occurred, have risen steadily, though
slightly, since 1955. Co~ercial fishing in Newfoundland
waters totalled 2.0 million lb, or 2~ below the 1960 level.
Maritime angling in 1961 yielded 26,487 fish, 13% more than
in 1960, but was still far Jfelow the average of the 1949-5'8
period~ About three quarters of the total angling catch comes
from the Miramichi River~ where supplies of adults during
recent angling seasons have been sub-normal as expected from
DDT effects" Average catch per 10 rod-days of angling effort
in 1961 was 2ol for the whole Maritime region, as in 1960, but
in the three component areas the values compared to those for
1960 were: Gulf, 4.9 compared to 4.2 in 1960; Fundy, 0.7 compared
to 1.7.in 1960; Atlantic, Oo6 compared to Oo4 in 1960. Newfoundland
rivers gave 17,o48 fish by angling in 1961, or 7% fewer
than in 1960 and angling catch per 10 daysu effort was 4.6
compared to 5 ,, 0 in 1960"
In 1961 catch records for the controversial Miramichi
drift-net fishery, Miramichi estuarial trap nets and angling
along with temperature and water level records have been
examined mainly to see whether or not any clear relationship
exists between anglers' and drift netters' catches. Drifters'
catches appear to have had little effect on abundance of large
fresh-run salmon in the Miramichi system.
Operation of research sampling traps and counting
fences in the Miramichi area annually through the open-water
period provides additional information on abundance of salmon.
In 1961 grilse entered the estuary in normal abundance as
expected from an estimated good smelt run from the river system
in 1960; but 2-sea-year salmon were scarce, as expected. On
the Northwest Miramichi tributary noticeable recovery had
occurred by 195'9 from DDT sprayings in 1954 and 1956, but mine
pollution deterred upstream migration of adults in 1960. In
1961 some improvement from the latter was noted in the ascent
of good numbers of 2-sea-year adults, but the grilse run was
f~r belo~ normal, perhaps an effect of mining effluent on 1960
survival of smelts from this brancho
Production of voungo Studies since 1941 on the Pollett
River, tributary to the Petitcodiac, were focuss-ed first on best
use of hatchery stock, but for several years have been aimed
mainly at learning spawning requirements for optimum natural
smelt production with predatory birds controlled the year round.
These studies (Summary No. 67) combined with regular observations
on other Maritime streams have_ led to a useful summary of the

- 22 =
survival rates under good, averag-e, and poor environmental
conditions, from eggs laid by typical pairs of spawning adults
through the several stages of young salmon to adultso River
stock requirements to fill -the rearing capacity (without bird
control (see below)) of 1 to 2 smelts per 100 yd amount to about
10 adults (50 lb of females} per mile length and 10 yd width
of river. Present Maritime runs often approximate and sometimes
exceed this rate; but exceptions are streams heavily developed
for hydro-el~ctric power or heavily sprayed with insecticideso
The 1961 Pollett studies included observations started
in 1957 on use of hatchery-reared large yearling salmon for
reinforcement or smelt runs estimated to be deficient by prior
electro-seining assessments of parro Estimates based on
recoveries from a tagged sample indicated that all survivors
of a late fall planting of 10,000 in 1960 descended as smelts
during the 1961 migrationo It raised an otherwise deficient
smelt run to a better-than-average level. Other stocking
experiments involving plantings of tagged hatchery-reared smelts
having different rearing histories were started in the Miramichi
and Margaree Riverso
Distribution and utilization cf salmon of Miramichi
origin. Annually since 1950 efforts have been made to mark by
fin-clipping large numbers of ·smelts as they descended Miramichi
tributaries, for various purposes including estimation of total
Miramichi smelt production by estuarial sampling, estimating
contributions of Miramichi smelts to various Atlantic fisheries,
and the extent of homing (Summaries No. 65 and 66). Total marking
effort has varied greatly from year to year, depending on time of
installation of counting and marking traps, which is often delayed
by log drives and high water. In good years about 50,000 smelts
have been marked. Data on fin-clipping returns from 1950 to 1959
are now being summarized for publication. Angling an.d commercial
fisheries plus adult counting fences at the lower levels of the ·
study streams have given total returns averaging about 2.5% from
smelts marked in different yearso Exceptions are higher returns
of about 10% from markings in 2 years when minimum numbers (under
2,000) were fin-clipped; the cause cannot be identified but may
. be related to extreme lateness of markingo
Starting in 1958 annual small-scale experiments have
been undertaken using a smelt tagging technique developed in
Sweden. Over 17,000 tags have been applied altogether, and adult
returns range from 0.8 to 2o5% and give precise information on .
captures of Miramichi fish in commercial ne-ts at sea as far away
as Greenland, by anglers, and at the local counting traps. It
is planned to substitute tagging for fin-clipping in many future
experiments to overcome problems caused by fin regeneration and
ether identification difficulties associated with fin-clipping.
Environmental changes. Improvement of natural conditions
affecting survival of young salmon up to the smelt stage in streams

= 23 -
is one objective of the res.earch program. One of the most
promising method-s is to control fish-eating dueks which can
take a heavy toll on many Maritime rivers and nullify other
useful manipulation practices. Earlier experiments showed
that smelt production can be increased several times by
thorough merganser control. It now remains to demonstrate
convincingly that the benefits can carry through to adult
salmon and improve salmon catches. A 5~year base-line survey
of young salmon and mergansers was completed for the Margaree
River in 1961, and shows that production of smelts is at
present limited by merganser predation. Detailed analysis of
available angling and commercial catch statistics show that
future fishing success in the Margaree area can be used to
gauge effects of merganser control. It is hoped to begin a
5-year experimental merganser control operation in 1962 on the
Margaree, to show whether or not it can be considered to be a
practical salmon management procedure (Summary Nco 68).
Harmful man-made changes affect salmon production in
many Maritime streams. Recently evaluation of effects of
forest sprayings with DDT to control budworms, and effluent
from mines, have needed much research effort" The objective
is to show the seriousness of the situation affecting salmonids
and to assist whenever possible by recommending suitable remedial
measures. Some attention has been given also to the problems
of power dams and deforestation (Summary No. 69).
Field studies of salmonids and stream invertebrates
were made in 1961 in connection with regular DDT spraying
operations over 2 million acres of woodland and rivers in central
New Brunswick, and also with experimental spraying for fisheries
assessments on the Molus River in Kent County.
They showed that
single half-strength spraying

- 24 -
returned to normal aft-er being sever--ely reduced immediately
after sprayinga Numerically the total production of insects
quickly recovered, but at first the insects were mainly smaller
forms, eogo' midges, and the larger species, e.g.' caddisflies
which are more suitable food for larger parr, have been slow to
return.
Physiology. The ability to regulate buoyancy may
be an important factor affecting survival of salmonids in
nature, and should be considered in artificial stocking programs.
Preliminary field experiments with parr collected in slow and
fast water during 1961 showed marked buoyancy differences; fish
from slow water were more buoyant than those used £o fast water.
In later better controlled laboratory experiments young salmon
adjusted rapidly to changing water velocities (Summary No. 71).
Increased velocities were.followed by decreased buoyancy and vice
versa, in less than 24 hours" Further studies are planned to
measure buoyancy regulation differences between salmon and trout,
and the relationship between ability to regulate buoyancy and
size of fish from fry to smoltso
Laboratory studies were started of cruising speed
(maximum rate or swimming that can be maintained for an hour)
of salmon parr in a rotating circular trough. For ,arr weighing
2 to 11 gm, cruising speeds were 40 to 84 feet per minute,
increasing over this range with size of fish. The results will
be useful as background for investigations of possible weakening
effects of pollutants like DDT, copper and zinc (Summary No. 70).
TROUT
There is a substantial and increasing use of fresh
waters in the Maritimes for recreational fishing, and potential
growth is great. Work on trout and limnology in general studied
the limiting factors on production of fish in various areas and
how production can be improved by exercising increased control
over environments and fish populations"
Forming a pond on Prince Edward Island trout streams
showed that initially retention and accumulation of fish in the
pond improved anglers 1 catcheso They later declined to a level
sustained by the annual recruitment of trout of catchable size
from the tributaries (Summary No. 58). Alteration of tributary
stream habitats to provide more shelter increased -standing crops
of young trouto However~ it nas not yet been shown that annual
recruitment to the pond will be materially incr-eased-as a result
(Summary Noo 59)o Hatchery-reared trout (uooeryearlings) planted
in an unfished pond survived poorly and did not increase the
standing crops ft•om native reproduction (Summary N-o. 60)o Tests
showed that trout populations are used more effectively by
harvesting every year than in alternate yearso
Pond formation on Ellerslie Brook reduced the trout
run from the brook into the estuary and neighbouring salt water.

- 25 -
In an attempt to compensate, marked hatchery-reared brook trout
were planted directly into the estuary in early winter, 1962,
(Summary No. 61). The planted trout were of a size shown
experimentally to tolerate adjustment to estuarial conditions.
Results to date from a continuing experiment show
that the non-indigenous rainbow trout and indigenous brook
trout, when not in competition with each other, utilize and
survive in a New Brunswick lake habitat to provide about equal
yields to anglers (Summary No. 62). In a Prince Edward Island
pond, with competition between them, the rainbow trout appears
to dominate, and would possibly supplant, the brook trout with
opportunity for equal recruitment.
POLLUTION
Natural waters have many uses. Undisturbed they
provide fish with the home for which they are adapted. However,
industrial and urban advances often interfere with the suitability
of water for fish. Important problems in the Maritime Provinces
are agricultural poisons such as DDT, industrial wastes.such as
those from pulp mills, contamination of edible fish by sewage,
and less obvious changes associated with land use. A necessary
tool for combating these dangers is basic scientific knowledge
of the manner in which pollution affects fish. The small
pollution group at St. Andrews attempts to provide basic answers
for some of the problems. It is hoped that other agencies can
use these facts in pollution-control work.
Effects of sub-lethal zinc and copper pollution. The
major research project concerned heavy-metal pollution of the
Northwest Miramichi River. Originating at a mine, this pollution
had seriously interfered with salmon spawning migrations in 1960,
and had reduced the numbers of resident young salmon as well as
their food organisms. Extensive control efforts at the mine
improved conditions in 1961, but did not completely cure them
(Summary No •. 75).
The ~ovements of migrating salmon were well-documented
at the salmon counting fence a~ Curventon (Summary No. 76). In
1961 14% of all the salmon which moved upstream came back down
again, compared to 22% in 1960. In the previous 6 years, overall
downstream movements had never exceeded 3%, and were usually
less than 2%. Half of the fish which returned downstream did
not reappear. Since the homing of salmon is known to be very
precise, it is thought that pollution caused a serious loss of
spawning stock in the Northwest Miramichi River.
A~ an objective for pollution control, it was desirable
to provide a valid scientific estimate of the "safe" level of
pollution for undisturbed salmon migrations (Summary No. 77).
Such a safe level was thought to be affected by varying levels

- 26 -
of both zinc and copper, and by the modifying effects of seasonal
changes in basic water chemistry. By expressing zinc and copper
as fractions of their lethal levels, they could be added together
to provide a single index of pollution. Normal seasonal changes
in water chemistry were part of the preliminary calculations in
estimating this "toxicity index". Good correlation between salmon
movements and the toxicity index suggested that the safe level
was about 15% of the lethal concentration. Last year 1 s preliminary
"safe 11 estimate based on zinc alone was shown to be
inadequate.
Young salmon were held in cages at various points in
the Northwest Miramichi. During times of heavy pollution,
mortalities in the cages coincided with theoretical times to
death which were calculated from the concentrations of zinc and
copper (Summary No. 78). This verified that these two metals
were the only dangerous components in the pollution. When
pollution was only 10% to 20% of the lethal level, there was no
apparent deleterious effect on growth or condition of young
salmon held in cages. Some anomalous results seem to indicate
that the summation of stress from high temperature and sub-lethal
pollution caused mortality.
Lessened pollution in 1961 allowed a partial recovery
of fish-food organisms. In the previous year, mayflies, an
important part of the diet of very small salmon, had virtually
disappeared from 15 miles of the Miramichi. By the end of 1961,
they had recovered somewhat, and abundance averaged about 40% of
that in unpolluted areas (Summary No. 79). An over-abundance of
caddisflies, the other major food item, might not entirely
compensate for low numbers of mayflies.
Reduced populations of young salmon were again found
to result from pollution (Summary No. 80). Since many adult
spawning fish did not reach headwater areas last year, the
resultant crop of fry in 1961 was very low in the headwaters.
Because of the same interference wi.th migration upstream, there
were large numbers of salmon available for spawning in the
polluted lower reaches. In spite of many spawners, the crop of
fry present in 1961 was only one quarter of the usual number.
Metal pollution in the lower section either killed eggs or fry,
or reduced their numbers by indirect action. All stages of
young salmon in the polluted lower section were much smaller
than their counterparts in head'w·aters, whereas they should have
been larger. However, these effects on growth were not so severe
in 1961 as in the previous year.
Pollution surveys in estuaries. Routine chemical
surveys were carried out in Saint John Harbour and the estuary
of the Miramichi River, to assess the seriousness of industrial
pollution (Summary NeG 81). Happily, the effects of waste
disposal were found to be slight in both places. In Saint John,

- 27 -
pollution by phenolic compounds-had been feared from a new
oil refinery. Only errati~ trac~s or phenol were round in the
harbour, no real chance from- conditions befo-re the refinery
started operating. Concentratio~s of phenol in the harbour
were 0.007 mg/1 or less, providing an adequate safety margin
even for tainting of fish flesh.
In the Miramichi estuary, there was reduction of
dissolved oxyJen in waters immediately adjacent to a pulp mill,
but no serious chances in the main channel or the river.
FISHERIES OCEANOGRAPHY
The study of the ocean environment as related to
fisheries was concentrated on the circulation, the variations
of the water properties such as temperature and salinity in
the coastal areas and on some or the fishing banks, and the
long-term deviations of such variations. The purpose of this
study is to gain a better understandinc of seasonal and annual
fluctuations of fish production and to forecast variations in
the environment.
Surface non-tidal drift. The area of study of the
surface non-tidal drift as indicated by drift-bottle releases
and recoveries was associated with studies or the distribution
of herring and lobster larvae. The Gulf of Maine and Bay of
Fundy drift-bottle experiment is related to herring investications
(Summary No. 82), and that of Northumberland Strait to lobster
investications.
The daily releases made at fixed stations such as .
Sambro and Lutcher Lightships and on the ferry bo...9-t-' CPR. Princess
Helene, CNR Bluenose, CNR Abegweit, and CNR William Carson
serve to monitor the circulation on an extended basis (Summary
No. 83). Analysis of recoveries from these daily releases over
a period of years, shows the general pattern or circulation in
the Bay of Fundy and the relationship between the Bay of Fundy
system and the Gulf of Maine eddy. It shows also the anomalies
from the general pattern. These anomalies are related to those
in the seasonal wind recime and in the run-off from continental
drainage. The Bay or Fundy circulation differed in 1961 from
1960. It was mostly "closed" in 1960 and nopen" longer than
usual into autumn in 1961. The Gulf or Maine eddy was stronc
late in 1961. Along the south coast of Nova Scotia, the nontidal
drift seemed to be more variable in 1961 than in 1960.
The circulation in and around S-t. Mary Bay. wa-s- studied
intensely from September 1960 until December 1961. -A seasonal
pattern of circulation is inferred from drift-bottle recoveries.
Starting in April, the wate~s of St. Mary Bay seemed to be
replaced more rapidly than durinc the preceding monthso In
summer drift bottles get in the main path of the Bay of Fundy

- 28 -
circulation, spread into the Bay of Fundy and reach the Quoddy
region in approximately 30 days. From July to September, the
escapement from St. Mary Bay decreases and this decrease
continues during autumn and winter.
The drift-bottle recoveries in Passamaquoddy Bay
show contributions from every fixed station west of Halifax.
It has been estimated that, when the drift into Passamaquoddy
Bay is at a maximum, one fifth to one quarter of the bottles
that escape Sto Mary Bay are recovered in Passamaquoddy Bay.
The releases and recoveries of drift bettles in the
northern sector of Northumberland Strait give further evidence
of an easterly and northeasterly movement of the surface waters
and a lack of movement of these waters to the south through the
Strait. The releases and recoveries in the central sector of
Northumberland Strait show very few recoveries to the north and
then for short distances only and a fair number (20%) to the
south. The main bulk of recoveries was made in the central
sector along the Prince Edward Island coast. The two series of
drift-bottle releases indicate that the two lots separated by
as little as 50 miles do not "intermingle".
Daily releases in Cabot Strait, started in August,
have shown, even with a very low rate of recovery, the drift
along the south coast of Nova Scotia and along the west coast
of Newfoundlando
European recoveries of drift bottles released in 1960
have been reported at the rate of 0.6% of the releases. The
average minimum speed of the bottles crossing the Atlantic is
of the order of 6-7 miles a day (Summary No. 84).
The recoveries from drift-bottle releases made on the
Scotian Shelf in March 1959 suggest a westerly movement of the
waters within 40 miles of the coast and an easterly movement for
the waters 70 miles from the coast or more (Summary No. 85).
Bottom circulation.. Two new "tools" developed in the
United Kingdom were used in 1961 to study the bottom circulation.
These are the sea-bed drifter, the counterpart of the surface
drift bottle, for the bottom non-tidal drift, and the Pisa tube
for current measurements on the bottom. Both were used in the
Gulf of St. Lawrence (Summaries No. 86 and 87).
The recoveries of sea-bed drifters mad€ in trawls and
drags seem to indicate that, along the Gasp' side of the entrance
to the Bay of Chaleur, the bottom waters are drifting in a
southwesterly direction as part of an eddy with the return drift
along the western slopes of Orphan Bank. The most frequent
drifts were of the order of 0.14 and 0.28 mile per day.

~ 29 -
The Pisa tubes were used for periods of one and two
tidal cycles at two stations to measure the residual current
on fishing bankso They were used also at fishing stations and
in the Laurentian Channel to measure the speed or the current
as an environmental factor.
The variation in the vertical thermohaline structure
along the longitudinal axis or the Laurentian Channel has been
considered as a means to estimate the average speed of the deep
layer in Cabot Straito
Temperature and salinity. Twice daily monitoring of
surface water temperatures at six shore or coastal stations
along the Canadian Atlantic coast continued during 1961 (Summary
No. 90). The 1961 temperatures, at all stations, revealed a
general decrease from the 1960 valueso The late disappearance
of ice in the Gulf of St. Lawrence was responsible for abnormally
low temperatures in the southern Gulf during the spring. The
effect on the average of the very low temperatures during the
first 6 months was reduced by higher than 1960 temperatures
during the last 6 months, mainly in Halifax Harbour and in the
southwestern Gulf of Sto Lawrence. The b961 for~cast of annual
mean temperature for §t· Andrsws was ?.0 C (44.6 F) and the
obs~rved
me~n was 8a8 C (44o2 F). Thg forecast for 1962 is
between 6.8 Q~4.2 F) and 7.0°C (44.6 F).
Quarterly observations of temperatures and salinity
in the central sector of the Scotian Shelf show a great similarity
between conditions observed in 1961 and in 1959 with a welldeveloped
intermediate cold-water layer and temperatures lower
than average at depth and near the bottomo Low temperatures and
relatively high salinities near the coast suggest upwelling along
the coast in August (Summary Nco 91).
The bottom temperatures on fishing grounds such as
Emerald Bank were below average all year (Summary No. 92). In
the coastal areas near Sambro Lightship and Lurcher Lightship,
the 1961 bottom temperatures were at an all time low (since·the
beginning of the fifties). On the New Brunswick side of the Bay
of Fundy, the 1961 bottom layer temperatures (?5-90 metres) were
lower than those or 1960 but not as low as those of 1959.
The stratification of the waters alone the slopes of
the Laurentian Channel in the early winters of 1960 and 1961
was studied guring A. T. Cameron cruises (Summary No. 93). The
zone 0.0-2.0 C, in both years, was shallower to the north of
Magdalen Isl~nds than to the southeast. The thickness of the
zone 2.0-4.0 C also seemed to vary alone the slopes, being
reduced to the southeast. Comparison with 0
previous data obtained
in the area sucgests that the zone 2.0-4.0 c cenerally has a
tendency to be thicker north of the Magdalen Islands than in
Cabot Strait off Cape North.

- 30 -
New long-term averages (1948... 1961) ~f temperature and
salinity at three depths were computed for the waters of the
northern sector of Northumberland Strait (Summary No. 94).
Conditions in this area during 1961 are those resulting from a
very slow warming in the spring and slow cooling in th~ autumn.
In May the surface temperatures were approxim~tely 2o5""C lower
than averageo In October they were about 1.5 C above average.
The bottom waters at 20 metres were always below average except
on two occasions. By the middle of July the bottom temperatures
were as low as those of the beginning of June in average years.
Long-term variations in temperature. The long-term
variations of water temperatures along the Canadian Atlantic
coast show that the cooling trend which followed the intense
warming of the forties and the beginning of the fifties is still
continuing {Summary No. 95). This cooling trend is not only a
surface phenomenon. Cooling of the bottom waters proceeds at
about the same rate as the surface waters.
The variations of species composition, cod~haddock
ratio in commercial catches during the last 45 years,are related,
with some reservatioos 9 to the changes in the environment, the
long-term temperature variation (Summary No. 97).
Heat budget. Following a previous study of heat
budget in the Gulf of St. Lawrence, the amount of evaporation
was calculated for a 24-month period. The difference precipitationevaporation
shows a seasonal variation, more pronounced in the
southern than in the northern Gulf (Summary No. 98).
MATHEMATICAL STATISTICS
Mathematical statistics is a service investigation
within the St. Andrews Station occupied on the one hand with
mechanical processing of fisheries data for biological studies
and on the other with mathematical and statistical analyses of
biological phenomena.
In 1960 the Station acquired IBM machines for handling
data arising primarily from census surveys by research vessels.
The initial effort which went into planning the data handling
procedure has proven profitable. Many of the biological data
are now processed in a more or less routine manner and are ready
for a more detailed analysis than was previously possible.
The research aspect of the group·' s work is- mcstly
concerned with assisting biological inv-e-stiga-tors in their
analysis of data as well as with carrying out co-ordinated
research into the basic relationship between population phenomenon
and their manifestation in data collected by the Biological
Station. The long-term aim of these studies is to formulate
with biological investigators the dynamics of population growth
of fishes.

- 31 -
In the past year these studies have included investigation
of the fishing mortality g-enerated by),fishinc fleets on
our offshore banks (Summary No. 102). Results have mainly shown
a need for further clarification of the relationship between _
fishing effort~ in terms of sear chin& by vessels.,- and the catch,
before it is possible to obtain reliable estimates of the rates
of fishing and natural mortalityo Analysis ot lobster data has
resulted in a new method of estimation and bas shown that the
population sizes on commercially fished arounds can be estimated
from catch, effort, and temperature data collected by the lobster
investication. A by-product or the analysis reveals a simple
relationship between the catch and temperatureo These studies
provide a basis for decidinc on the sorts of productivitystuc!ies
of lobsters which will be required if attempts are ever to be·. · ·
made to increase the catch from a given lobster ground (Summary
No. 103).
Most of the biological data coll,~cted by the Station
is obtained by sampling the given universe under investigation.
One of the basic problems of the ··statistics group is to study
the sampling procedure ueed by biologists a.Qd to determine the
relation between the population and sample" 'the completion· of
such a study of sampling of research vessel catches is reported
in Summary Nco 104. Analysis of sampling the commercial groundfish
catches for length and age composition is reported in
Summary No. 105. The study shows the accuracy at which the
commercial catches are currently sampled and how precisely we
may determine the growth rates of cod and haddock~
SMELT
Complaints that the 1960-61 smelt fishery of the
Miramichi was less than 10% that of earlier years led to a shortterm
investigation which showed that, though the total catch was
actually the lowest during the last 15 years, the average catch
per net licensed was 882 lb compared to the 15-year average or
608. Log-book records showed also that per net~day fished the
catch was 9.4 lb compared to the 10-year average of 9.2 lb.
Surveys of the 1961 spawning run indicated that the stock was
not drastically reduced. Because of the unusually extensive
ice cover in the Gulf of St. Lawrence which lasted well into May
the smelt probably remained outside the Miramichi fishing area
until the fishery ended, entering only in time for spawning
after a spring 11 break-up'' which was the latest in 130 years
(Summary No. 101).
INSHORE COD
Cod are available to Newfoundland traps for a very
short period. This leads to inefficiencies in operation. Two
studies were undertaken to yield information that could be
applied to· lengthening the processing season by holding cod
alive.

- 32 -
Observati-ons at Burin, 'Nfl-d., (Summary No-. 73) were
made on attempts to hold su-bs-tantial quanti ties -of cod in a
large floating crate. In 39 days about 10~ or the fish were
lost by death. The usefulness or this method depends on Whether
a 10~ loss or fish can be tolerated. ·
As holding cod for processing is likely to require
close confinement, oxygen consumption was studied in laboratory
tests (Summary No. 72). It was round that oxygen consumption
is greater in feeding fish than tasting ones. Small fish use
more oxygen per ppund than large ones. Oxygen consumption per
fish is rsduced by crowding. Temperature differences between
;o and ;9 F had little effect on oxygen consumption. The work
is being continued.
BULLETIN ON ATLANTIC COAST FISHES
Work on this much neededbulletin was disrupted by the
death or Dr. A. H. Leim who was to have been the author and was
monitoring- the effort on it. Arrangements tor continuing work
on the manuscript and preparing it tor publication are now in
hand.

STAFF LIST Br INVESTIGATIONS
(April 1, 1961 to March 31 9 1962)
Staff other than seasonals and term are classified as of March 31, 1962.
Director
Director's Secretary, Clerk 4
J o L. Hart !I
PhoDo
Winifred E. Young
Assistant Director,Pri.ncipal Scientist L. R. Day, MoAo
Groundfish Investigations
Principal Scientist in charge
Senior Scientist
Senior Scientist
Associate Scientist
Associate Scientist
Associate Scientist
Technician 4
Teclmician 3
Technician 2
Technician 1
Technician 1
Technician 1
Technician 1
Technician 1
Assistant Technician 2
Assistant Technician 2
stenographer 3
Stenographer 3
Clerk 1 - Term
Technician 3 - Term
Technician 2 • Term
Technician 2 - Term
Student Assistant
student Assistant
Student Assistant
Student Assistant
Port Observer - Part-time
Port. Observer - Part-time
W. R. Martin!/ Ph.D.
L. M. Dickie, Ph.D.
F. D. McCracken, Ph.D.
Y. M. L. Jean, Ph.D.
A. C. Kobler.? Ph.D.
P. M. Powles, MoSe.
G. J. W. Sullivan
D. N. Fitzgerald
N. J. McFarlane
(edueatiorlal leaw to
May 1/61.) (educational
lea'Ve trca Jan. 11/62)
G. J. DeLouehry, B. A.
M. F. Fr~er
R. M. l4a.cPherson
J. A. Maillet, B.Se. (to Dee. 22/61)
R. J. 'l'hurber
R. K. Ro bieheau
Irma I. 'l'hampson
Shirley W •. DeLong
C. Ruth Garnett
Miriam R~ Carson (Feb. 1 - March 30/62)
T~ T. Miyata; B.sc. (fran oct. 17/61)
R. J ~ GibSon, B.A. (fraa Oct. 2/61)
A. E. Neumeyer, B.A. (to Aug: 3i/61)
Janice I. Bartlett, B.Se. (Hay 24 - Sept. 7/61)
H. Hirata, Ph.D. (May 5 - Sept. 28/61)
D. H. Steele, Ph.D. (May 17 - Sept. 22/61)
I. R. Wool.frey, B.Se. (May 29 - Sept. 1/61)
F. Berrigan
R. c. MacMillan
Anadranous Fishes
(a)
SaJ.mon Investigations
Principal Scientist in charge
Associate Scientist
Associate Scientist
Associate Scientist
C. J. Kerswi.ll, Ph.D.
P. F. Elson, Ph.D.
M. H. A. Keenleyside, Ph.D. (to .tug. 4/61)
R. L. Saunders, Ph.D.

- 2 -
Assistant Scientist
Technician 2
Technician 1
Teclmician 1·
Assistant Technician 3
Assistant Technician 2
Assistant Technician 2
stenographer 2
stenographer 2
Assistant Technician 3 ~ Term
Assistant Technician 3 ~ Te~
Assistant Technician 2 ~ Term
Assistant Technician 1 ~ Term
Assistant Technician.l- Term
Assi5tant Technician 1 ~ Term
Assistant Technician 1 ··~
Term
Assistant Technician 1 - Term
Student Assistant
Student Assistant
Student Assistant
student Assistant
Student Assistant
Student Assistant
Student Assistant
Student Assistant
Casual employees
(b)
Trout Investigations
Senior Scientist in charge
Associate Scientist
Technieian 1.
Assistant Technician 3
~ Assistant Technician 2
Student Assistant
Pond Guardian
Pond Guardian
Casual employees
* Also general laborator.y assistance
J. H. Gee, MoSCo (from Nov. 17/61)
E. Jo Schofield
P. R. Graves
I. M. ·Jones
W. Go Irving
H. P •. ~chard
L. R. MacFarlane
Ruth M. Barr (to Jan. 12/62)
R. Marion Haley (from Jan. 22/62)
G. W. Cooper (Apr. 4 - Dee. 2/61)
E. F. T}?.ompson (June 1 - July 31/61)
W. H. MacLean (May 1 - Sept. 8/61)
W. R. Currie (Apr. 4 - Nov. 30/61)
E. K. Geldart (Apr. 4 - Dec. 23/61)
(Mar. 7 - Mar. 31/62)
J. H. King (Apro 4 - Dee. $/61)
V. R. furphy (Aug. 7 ,_ Sept. 24/61)
E. c. Tucker (Apr. 4 - Dee. 7/61)
R. B. Bartlett (May 26 - Sept. 19/61)
Eo A. J. Chambers (May 10 - Sept. 15/61)
R. J. Gib9on 1 B.A. (May 12 - Sept. 22/61)
C. D. Grant (May 16 ~ Sept. 12/61)
B. Hicks (June 1 = Aug. 1$/61)
D. A. G. Mickle (May 15 - Sept. 19/61)
R. H. Peterson (May 15 - Sept. 15/61)
R. G. Steele (May 15 - Sept. 12/61)
M. W. Smith, Ph.D.
J. W. Saunders, M.Sc.
C. Rc. Hayes
c. Williams
Mary Holmes
B. F. Fordj B.Sc. (May 31 - Aug. 25/ 61)
W. A. Simpson
J. Stevenson
Crustacea
Lobster Investigations
Principal Scientist in charge
Associate Scientist
Associate Scientist
Teclmician 2
Technician 1
Assistant Technician 3
Clerk 1
Assistant Technician 1 - Term
Student Assistant
Student Assistant
D. G. Wilder, Ph .. D.
D. W. McLeese, Ph.D.
D. J. Scarrattjl Ph.D. (from Sept. 27/61)
R. c. Murray
U. J. Walsh
D. E. Graham
F. Willa Williamson
G. A. Sollows (to July r9t61)
·Susan Corey (May 8 - Sept. 14/61)
Alina Walther, B;;Se. (May 17 - Sept. 22/61)

- 3-
Pathology
Associate Scientist in charge
Senior Scientist - !erm
J. Demelker, M.Sc.
M. Laird, D.Sc. (June 23 - Aug. 15/61)
Herring (Pelagic)
Senior Scientist in charge
Associate Scientist
~~sistant Scientist
Technician 1
Technician 1
Technician 1
.Assist.ant Technician 3
.Assistant Technician 3
Assistant Technician 2
ASsistant Technician l
Stenographer 2
Student Assistant
student Assistant
S. N. Tibbo, M.A.
R. A. MCKenzie, M.A.
T. R. Graham, M.Sc.
A. W. Holt
c. F. Monaghan
E. G. Sollows
A. W. Brown
C. i.. Dickson
Cariene D. Burnett
w. H. Dougherty
Janet L. Mahoney
N. Das, M.Sc .. (May 18 - Oct. 11/61)
D. G. Wallen (May 8 - Sept. 27 /61)
Mollusca
Senior Scientist in charge
J. c. Medcof, Ph.D.
(a)
Clam and Scallop Investigations
Associate Scientist in charge
Associate Scientist
Technician 3
Assistant Technician 3
Student Assistant
Student Assistant- IDS
Casual employees
N. F. Bourne, Ph.D.
A. Prakash, Ph.D.
J. So MacPhail
Esther I. Lord
Jessie J. Doncaster, B.Sc. (May 15- Sept.8/61)
A. R. Mciver, B.Sc. (May 1 - Oct. 4/61)
(b)
Oyster and Quahaug Investigations
Associate Scientist in charge
Technician 2
Technician 1
Maintenance Supervisor 1
Stenographer 1
Associate Scientist - Term
Technician 1 ... Term
Technician 1 - Term - IDS
Assistant Technician 1 - Term
Student Assistant
Student Assistant
student Assistant
Casual employees
R. E. Drinnan, B.Sc.
S. E. Vasa, B.Sc.
E. B. Henderson
K. R. Oatway
Mary-J. -Williams (from July 1/ 61)
W. B. stal.lworthy, Ph.D. (May 23 - Sept. 18/61)
B. 'f. Khouw
E. c. Durkee (June 8 - Nov. 3/61)
R. R. Payne (June 26 - Sept. 1/61)
Mary I. Arsenault (June 1 - Sept. 15/61)
Austina V. Kennedy, B.Sc. (Mq 1.5 - Sept. 7/61)
Catherine B. Sheldon, B.Sc. (June 5 - Sept.l/61)

- 4-
Biological Oeeanograpgv
Senior Scientist in charge
Technician 3
Technician 2
Senior Scientist - Term
Student Assistant
L. M. Lanzier, D.Sc.
J. G. Clark
J. H. Hull
D. G. MacGregor, Ph.D. (July 25 - Sept. 6/61)
V. S. S. Keru:tedy (May 8 - Sept. 14/ 61)
Pollution Studies
Associate Scientist in charge
Technician 1
Clerk 1 - Term
J. B. Sprague, Ph.D.
W. V. Carson, B.Sc. ·
'l'herese M. Parker (Apr. 17 - May 26/61)
Mathematical Statistician
Senior Scientist in charge
Teclmician 2
Associate Scientist - Term
Clerk 1 - Term
Assistant Technician 1 - Term
J. E. Paloheimo, M.A.
G. S. Mann, B.Sc.
W. R. Knight, Ph.D. (May 8 - Aug. 7/61)
Therese M. Parker {May 29/61 - Mar. 31/62)
Nancy L. McKinney (to Apr. 10/61)
Short-term Investigations and Technical Services
(Museum, Library, Photography and Drafting, Observer)
Principal Scientist in charge
Technician 1
Technician 1
Assistant Technician 2
Assistant Technician 2
Clerk 2
Student Assistant
Student Assistant
L. R. Day, M •.A.
P. W. G. MoMullon
F. E. Purton ..
F. B. Ctinningham (from April 2h/61)
G. C. Cyr (to April lh/61)
M. Beryl Stinson
B. Ann Ramsay (May 15 - Sept. 15/61)
Sharon L. Wood (June 1 - Aug. 31/61)
Administration and Maintenance
Administrative Officer 3 in charge
!dmiriistrati ve Assistant
D. S. Mann, M.B.A.
W. D. Burton
Accounts, Purchases, Stores and Persormel
Clerk 3
stenographer 2
Storeman 2
Frances L. Stinson
Charlotte A. Gibson
B. H. Foster
Director's Secretary, Mail, Files and Switchboard
Clerk 4 in charge
Stenographer 2
Clerk 2
Winifred E. Young
M. Barbara stickney
Dorothy M. McLaughlin

- s-
stenographer 1
Clerk 1
Stenographer 1 -
Typist 1 - 'l'erm
Student Assistant
'l'erm
Frances J. Armstrong
Dorothy M. Fawkes
Margaret A. Harriott (June 26 - Aug.ta/61)
(Sept. 1 - Sept. 29/61)
Joan c. Gowan (July 24 - Aug. 31/6l.)
WinnU'red K. King
Maintenance, Services and Boats (St. Andrews)
Technician 4 in charge
Maintenance Supervisor 1
Maintenance Craftsman 1
Maintenance Helper
Maintenance Helper
Caretaker 4
Caretaker 3 (Grouridsman)
Caretaker 3 (Nets,maintenance,ete.)
Watchman
'l'ruckman
Cleaning Service Man
Laboratory Helper
H. Y. Brownrigg
F. M. Langley
P. M. Green
J. F. Jolmson
F. G. Lord
K. W. Jolmston
D. A. Stinson
C. s. Tucker
H. E. Lee
G. F. Wentworth
C. E. 'l'eakles
H. Mo Sampson (from May 1/ 61)
M/V "Harengus"
Technician 3 (Capt.)
Chief Engineer
2nd Engineer
2nd Engineer
Mate
Boatswain
Cook-steward
'!'wine hand
'!'wine hand
Twine hand
Deckhand
Deckhand
H. H. Butler
H. Yarn
I. M. Corkum· (to July 31/61)
s. Evans (from J:uly 27/61)
E. A. Mason
W. J. Horne
E. Kendall
E'. B';. Fevens
L. v. Richard (on leave N.s.w.c.B. f'rom
June 20/61)
'1'. V. Richard (.from June 26/61)
D. D. Goodwin {to Jtme 26/61)
V. Richard (from June 29/ 61)
M/B "Mallotus"
*Technician 1 (Capt.)
Deckhand - '!'em
w. G. Carson
F. R. Jolmson
t Responsible to .&ssistant Director tar technical. aspects or work
M/B "Pandal.us II"
Captain
Engineer - Tem
Engineer - Term
Engineer - 'l'erm
Cook-deckhand - Term
P. '1'. Ossinger (from April 4/ 61)
R. F. Long (June lU -. July 20/61)
L. P. Pyne (Apr. 13 - Sept. 8/61)
(LWOP Jl:me 9 - July 2~61)
A. Do Roberts (Sept. · 11 - Nov. 8 61)
A. MacDonald (Apr. 10 - Novo 8/ t)

SC!EftiFIC STAFF
Biological Station, St. Andrews, N. B.
J. L. Hart, Ph.D. (Toronto), F.R.s.c., Director.
L. R. Day, M .. A. (Western Ontario), Assistant Director.
Biological Oceanograpgy
L. M. Lauzier, D.Sc. (Laval).
D. G. MacGregor, Ph.D. (Mount Allison). Term, July 25 to September 6.
Groundrish
W. R. Martin, Ph.D. (Michigan).
L. M. Dickie, Ph.D. (Toronto).
F. D. McCracken, Ph.D. (Toronto) •
Y. M. L. Jean, Ph.D. (Toronto).
A. C. Kohler, Ph.D. (MCGill).
P. M. Powles, M.Sc. (Western Ontario).
Lobster
D. G. Wilder, Ph.D. (Toronto).
D. W. McLeese, Ph.D. (Toronto).
D. J. Scarratt, Ph.D. (Wales). From September 27.
Mathematical Statistics
J. E. Paloheimo, M.A~ (Toronto).
W. R. Knight, Ph.D. {British Columbia). Term, May 8 to August 7.
Mollusca
J. C. Medco.r, Ph.D. (IDinois).
N. F. Bourne, Ph.D. (Toronto).
R. E. Drinnan, B.Sc. (London).
A. Praicash, Ph.D. (British Columbia).
W. B. Stallworthy', Ph.D. {Toronto). Term, Ma;y 2.3 to September 18.
Pathology
J. Demelker, M.Sc. (Leyden).
M. Laird, D.Sc. (New Zealand). Term, June 23 to August 1.$.
Pelagic
S. N. Tibbo, M.A. {Toronto).
R. A. McKenzie, M.A. (Toronto).
'f. R. Graham, M.Sc. (Liverpool).
Pollution
J. B. Sprague, Ph.D. (Toronto).

Salmon
c. J. Kerswill, Ph.D. (Toronto).
P. F. Elson, Ph.D. (Toronto) •
M~ H. k.. Keen1eys~de, Ph.D. (Groningen). To .lllgust 4.
R~ L. Saunders, Ph.D. (Toronto).
J. H. Gee, M.Sc. (British Columbia). From November 17.
Trout
M. W. Smith, Ph.D. (Toronto).
J. W. Saunders, M.Sc. (Laval).
other
A~ G. Huntsman, M.D., F .R.s.c. (Toronto). Volunteer in,wstigator.
Vl8dis1ava J. steele, M .. Sc. (McGill). Volunteer investigator.
Charlotte P. Mangum, M.S.\ (Yale). Volunteer investigator.
M. D. B. Burt, M.Sc. (St• .Andrews). Volunteer investigator.

PUBLICATIONS
(January 1, 1961, to December 31, 1961)
Bailey, w. B. Canadian contribution to IGY Polar Front Survey,
North Atlantic, 1957-1958e Conseil Permanent International
pour l'Exploration de laMer, Rapports et Proc~s-Verbaux
des Reunions, Vol. 149, p. 92.
Brawn, Vivien M. Aggressive behaviour in the cod (Gadus
callarias L.). Behaviour, Vol. 18, Part 1-2, pp. 107-147.
Reproductive behaviour of the cod (Gadus callarias
L.). Behaviour, Vol. 18, Part 3, pp. 177-198.
Sound production by the cod (Gadus callarias L.).
Behaviour, Volu 18, Part 4~ pp. 239-255.
Campbell, N. J. Canadian IGY Project "Deep Water Circula tion 11
North Atlantic, 1958. Conseil Permanent International
pour l'Exploration de laMer, Rapports et Proces-Verbaux
des Reunions, Vol. 11+9, p. 114.
Day, L. R. Summer surface distribution of redfish larvae in
ICNAF Subarea 4, 1954-1955. International Commission
for the Northwest Atlantic Fisheries, Special Publication
No. 3, pp. 195-198.
' /
Drinnan, R. E., and J. C. Medcof. Progres du Retablissement
des stocks d'hu1tres decimes par la maladie. Office des
Recherches sur les P~cheries du Canada, Station Biologique,
St. Andrews, Circulaire, Serie Generale, No. 34, 3 pp.
Progress in rehabilitating disease affected oyster
stocks. Fisheries Research Board of Canada, St. Andrews
Biological Station Circular, General Series, No. 34, 3 pp.
Jean, Y., and F. D. McCracken. Incidental catches of redfish
in cod and haddock surveys off the southern Canadian
mainland during the years 1957 to 1959. International
Commiss~on for the Northwest Atlantic Fisheries, Special
Publication No. 3, pp. 142-147.
Kerr, Robert B. Scale to length ratio, age and growth of
Atlantic salmon in Miramichi fisheries. J. Fish. Res.
Bd., Vol. 18, No. 1, pp. 117-124.
Kerswill, C. J. The management of Atlantic salmon.
for Tomorrow Conference, Vol. 2, pp. 823-831.
Resources
Investigation .. and Management of Atlantic Salmon.
Part 1. The Research Programme. Canada Department of
Fisheries, Trade News, Vol. 14, No. 1, pp. 3-9.

- 2 ~
Kerswill, c. J. Review of 11 Six Salmon Rivers and Another"
by G. F. Clarke. canadian Geographical Journal, Vol.
LXII, No. 2~ pp. V-VII.
Foreword to "Queen of the River" by Roy Saunders.
Oldbourne Book'Co., Ltd. 9 London~ pp" 5-6.
Kerswill, C. J., and M. H. A, Keenleyside. Canadian salmon
caught off Greenland. Nature, Vol. 192, No. 4799, p. 279.
Kerswill, C. J., P. F. Elson, M. H. A. Keenleyside, and J. B.
Sprague. Effects on young salmon of forest spraying with
D.D.T. Transactions of the 1959 Seminar on Biological
Problems in Water Pollution. The Robert A. Taft Sanitary
Engineering Center, Technical Report W60-3~ p. 71, 1960.
Laird, Marshall. Urceolaria karyodact~ n" sp. (Ciliata:
Peritricha) from Ischnochiton ruber (L.) at Saint Andrews,
New Brunswick. Canadian Journal of Zoology, Vol. 39, No.
6, pp. 827-831.
. Microecological factors in oyster epizootics.
Canadian Journal of Zoology, Vel. 39, No. 4, pp. 449-485.
Lauzier, L. M. Canadian serial temperatures and salinities
relative to IGY sea level recording, North Atlantic 1957-
1958. Conseil Permanent International pour l'Exploration
de la Mer, Rapports et Proces-Verbaux des Reunions, Vol.
149, p. 114.
Logie, R. R., R. E. Drinnan, and E. B. Henderson. Rehabilitation
of disease-depleted oyster populations in eastern Canada.
Proceedings of Gulf and Caribbean Fisheries Institute, 13th
Annual Session, November 1960, pp" 109·-113.
McKenzie, R. A. The smelt fishery of the Miramichi, 1960-61.
Canada Department of Fisheries, Trade News, Vol. 14, No.
5-6' pp 0 13-16 0
McKenzie, R. A., and S. N. Tibbo. Herring movements in the
Bay of Fundy and Gulf of Maine, 1957 and 1958. J. Fish.
Res. Bd., Vol. 18~ No. 2, pp. 221-252.
MacPhail, J. S. A hydraulic escalator shellfish harvester.
Bull. Fish. Res. Bd., No. 128, 24 pp.
Martin, W. R. Summaries of Research 1959. A. Summaries by
Countries. I. Canadian Research Report, 1959. B.
Subareas 4 and 5. Annual Proceedings for the International
Commission for the Northwest Atlantic Fisheries, Vol. 10
for 1959-60, pp. 25-31.

- 3 -
Martin, W. R. The distribution of redfish catches landed on the
southern Canadian mainland, 1949-1958. International
Commission for the Northwest Atlantic Fisheries, Special
Publication No. 3, pp. 148-153·
Martin, W. R., and D. N. Fitzgerald. Canada (Maritimes)- 1958.
Length frequencies - cod. International Commission
for the Northwest Atlantic Fisheries, Sampling Yearbook,
Vol. 3 for 1958, pp. 49-53.
Canada (Maritimes) - 1959. Length frequencies - cod.
International Commission for the Northwest Atlant+c
Fisheries, Sampling Yearbook, Vol. 4 for 1959, pp. 3-8.
Martin, W. R., D. N. Fitzgerald~ J. M. Boulanger, and A.
Marcotte. Notes on the sampling data. Canada (Maritimes
and Quebec). International Commission for the Northwest
Atlantic Fisheries, Sampling Yearbook, Vol. 3 for 1958,
p. 13.
Martin, w. R., D. N. Fitzgerald, and A. Marcotte. Notes on
the sampling data. Canada (Maritimes and Quebec), International
Commission for the Northwest Atlantic Fisheries,
Sampling Yearbook, Vol. 4 for 1959, p. xi.
Medcof, J. c. Trial introduction of European oysters (Ostrea
edulis) to canadian east coast. 1959 Proceedings, National
Shellfisheries Association, Vol. 50, pp. 113-12~. ·
Effect of hydraulic escalator harvester on undersize
soft-shell clams. 1959 Proceedings, National
Shellfisheries Association, Vol. 50, pp. 151-161.
Review of "Canadian Atlantic Sea Shells" by E. L.
Bousfield. Canadian Field-Naturalist, Vol. 75, No. 3,
p. 161.
Oyster Farming in the Maritimes.
No. 131, 158 pp.
Bull. Fish. Res. Bd.,
Paloheimo, J. E. Studies on estimation of mortalities. I.
Comparison or a method described by Beverton and !Jolt
and a new linear formula. J. Fish. Res. Bd., Vol. 18,
No. 5, pp. 645-662.
Prakash, A. Distribution and differentiation of alkaline
phosphatase in the gastro-intestinal tract of steelnead
trout. Journal of Experimental Zoology, Vol. 146, No. 3,
pp. 237-251.

- 4 -
Saunders, Richard L. The irrigation of the gills in fishes.
I. Studies of the mechanism qf branchial irrigation.
Canadian Journal of Zoology~ Vol. 39, No. 5, pp. 637-653·
Smith, M. W. Bottom fauna in a fertilized natural lake and its
utilization 'by trout (Salvelinus fontinalis) as food.
Verhandlungen Internationale Vereinigung riir Theoretische
und Angewandte Limnologie, VolQ 14, pp. 722-726.
A limnological reconnaissance of a Nova Scotian
brown-water lake. J. Fish. Res. Bd., Vol. 18, No. 3, pp.
463-478. .
Fish ponds in Canada -- A preliminary account.
Fish Culturist, No. 29, pp. 3-12.
Tibbo, S. N., L. R. Day, and W. F. Doucet.
(Xiphias gladius L.), its life-history
importance in the northwest Atlantic.
No. 130, 47 pp.
Canadian
The swordfish
and economic
Bull. Fish. Res. Bd.,
Trites, R. W. Probable effects of proposed Passamaquoddy Power
Project on oceanographic conditions. J. Fish. Res. Bd.,
Vol. 18, No. 2, pp. 163-201" (International Passamaquoddy
Fisheries Board 1956-59, Scientific Report No. 31.)
Wilder, D. G. Banding lobster claws--a better way to inactivate
them. Canada Department of Fisheries, Trade News, Vol. 14,
No. 3, pp. 8-9.
Wilder, D. G., and D. W. McLeese. A comparison of three methods
of inactivating lobster claws. J. Fish. Res. Bd., Vol. 18,
No. 3, pp.: 367-375.
MANUSCRIPT REPORTS
(January 1, 1961, to December 31, 1961)
Lauzier, L. M.~ and J. H. Hull. Temperatures along the
Canadian Atlantic coast, 1950-59. MS Rept. Oceanogr.
and Limnol., No. 39, 13 pp.
,
Legare, J. E. Henri. The zooplankton of the Passamaquoddy
region. MS Rept. Biol., No. 707, 37 pp.
MacPhail, J. S. Building and testing a hydraulic clam rake.
MS Rept. Biol., No. 711, 10 pp.
Mortimer, Joan E., and P. J. Downer. Hydrographic and biotic
study of Sam Orr Pond, New Brunswick. MS Rept. Biol.,
No. 698, 61 pp. {Edited by J. C. Medcof.)
Paloheimo, J. E. Estimation of mortalities of Georges Bank
haddock. MS Rept. Biol., No. 714, 23 pp.

- 5 -
MANUSCRIPTS SDpMITTED FOR PUBLICATION
(January 1, 1961, to December 31, 1961)
Brawn, Vivien M. Physical properties and hydrostatic function
of the swimbladder of herring (Clupea harengus L.). J.
Fish. Res. Bd.
Dickie, L. M. Effects of fishery regulations on the catch of
fish. FAO Experts Meeting on economic effects of fishery
regulations, Ottawa.
Estimation of mortality rates of a Gulf of St. Lawrence
cod tagging. North Atlantic Fish Marking Symposium, Woods
Hole, Mass., May 1961. International Commission for the
Northwest Atlantic Fisheries.
Dickie, L. M., and J. Co Medccf. causes of mass mortalities
of scallops (Placopecten magellanicus) in the southwestern
Gulf of St. Lawrence. J. Fish~ Res. Bd.
Elson, P. F. The Pollett apron seine. J. Fisho Res. Bd.
Keenleyside, Miles H. A. Skin-diving obseTvations of Atlantic
salmon and brook trout in the Miramichi River, New
Brunswick. J. Fish. Res. Bd.
Keenleyside, Miles H. A., and Fred T. Yamamoto. Territorial
behaviour of juvenile Atlantic salmon (Salmo s4lar L.) •
. Behaviour.
Kohler, A. C. Use of tagging data in Subarea 4 cod growth
investigations. North Atlantic Fish Marking Symposium,
Woods Hole, Mass., May 1961. International Commission
for the Northwest Atlantic Fisheries..
'
Lauzier, L. M., and J. H. Hull. Temperatures along the
Canadian Atlantic Coast 1958-1960. Atlantic Progress Report.
McCracken, F. D. Comparison of tags and techniques from
recoveries of Subarea 4 cod tags. North Atlantic Fish
Marking Symposium, Woods Hole, Mass., May 1961. International
Commission for the Northwest Atlantic Fisheries.
Martin, W. R. Canadian Research Report, 1960. B. Subareas
· 4 and 5. Proceedings of the International Commission for
the Northwest Atlantic Fisheries.
Prakash, A. Status of paralytic shellfish-poisoning research
in Canada. Proceedings of the Shellfish Sanitation Workshop,
U.S. Department of Health, Education and Welfare,
Public Health Service.

- 6 -
Prakash, A., and J. C. Medcof. Hydrographic and meteorological
factors affecting shellfish toxicity at,Head Harbour, New
Brunswick. J. Fish. Res. Bdo
Saunders, J. W., and M. w. Smitho Physical alteration of stream
habitat to improve brook trout production. Transactions
of the American Fisheries Society.
Smith, M. W. Limnology of the Atlantic provinces of Canada
being Chapter VII of Limnology in North America. l5,th
Congress of International Limnological Association.
Tibbo, S. N. New records for occurrence of the white-tip shark,
Pterolamiops longimanus (Poey), and the dolphin, Coryphaena
hippurus L., in the northwest Atlantic.
MANUSCRIPTS SUBMITTED FOR PUBLICATION
(Previously reported)
Elson, P. F. Predator=prey relationships between fish-eating
birds and Atlantic salmon with a supplement on fundamentals
of merganser control" Bull. Fish. Res. Bd.
Ide, F. P. Effects of forest spraying with DDT on the insect
fauna of salmon streams in New Brunswick. (Summary)
Proceedings of the Annual Meeting of the Entomological
~ociety of Ontario.
~cCracken, F. D. Selection by large-mesh codends of flatfish
· and redfish. Proceedings of the Lisbon Conference
sponsored by ICNAF/ICES/FAO.
Effect of mesh size variation on selection span.
Proceedings of the Lisbon Conference sponsored by
ICNAF/ICES/FAO.
Hook selection for cod and haddockq Proceedings
of the Lisbon Conference sponsored by ICNAF/ICES/FAO.
Selection factors for cod and haddock with codends
of different materials. Proceedings of the Lisbon
Conference sponsored by ICNAF/ICES/FAO.

FILMS AND FILMSTRIPS
1961
The films and filmstrips listed below are on file
at the Board's St. Andrews Station. They are available on
loan for limited use upon request.
Commercial films
1. LOBSTERS ARE A COMMUNITY AFFAIR. 20 min. b&w sound 16 mm
Produced by National Film Board for Department of
Fisheries.
2. THE OYSTER MAN. 18 min. b&w sound 16 DUB
Produced by NFB for Dept. of Fisheries.
3. TRAWLS IN ACTION 23 min. b&w sound 16 mm
Produced for British Ministry of Agriculture and
Fisheries.
4. TRAWLS IN ACTION Part #1 17 min. b&w silent 16 DUB
Part #2
(project at sound speed)
Produced for.British Ministry of Agriculture and
Fisheries, 1950.
(Edited and included in part in 3 above.)
5. FISH AND THE SEINE NET 20 min. b&w sound 16 lllll
Produced for Scottish Home Department.
6. PROJECT SCALLOP
Produced by NRC.
FRB - St. Andrews films
7. C.G.S. A. T. CAMERON
8. OFFSHORE (GEORGES BANK) SCALLOP
FISHING
9. DIGBY SCALLOP GEAR PERFORMANCE
10. MECHANICAL SHELLFISH DIGGER AND
HYDRAULIC DREDGE
11. SPANISH PAIR TRAWLERS
12. PASSAMAQUODDY HERRING TAGGING
13. ELECTRO-FISHING FOR SALMON -
DUNGARVON R. 1952
6 min. b&w sound 16 IDDl
20 min. colour silent 16 mm
(project at sound speed)
20 min. colour silent 16 mm
(project at sound speed)
15 min. b&w silent 16 lllDl
(project at sound speed)
28 min. colour silent 16 mm
(project at sound speed)
7 min. colour silent 16 mm
(project at sound speed)
8 min. colour silent 16 mm
(project at sound speed)
8 min. colour silent 16 mm

14. HALIBUT LONGLINING
- 2 -
15. SALMON TERRITORIAL BEHAVIOUR
16. SALMON RESEARCH
17. SALMON 1961 PARR CENSUS
18. HERRING UNDERWATER TV
19. TROUT - ELECTROFISHING
Filmstrips
20. LOBSTERS ARE A CROP
Produced by NFB for Dept.
21. WHY LOBSTER CATCH VARIES
Produced by NFB for Dept.
22. HOW LOBSTERS GROW
Produced by NFB for Dept.
23. PACIFIC SALMON
Produced by NFB tor Dept.
20 min. colour silent 16 mm
(project at sound speed)
5 •in. b&w silent 16 mm
(project at sound speed)
20 min. colour silent 16 mm
(project at sound speed)
5 min. b&w silent 16 mm
6 min. b&w silent 16 mm
(project at sound speed)
8 min. b&w silent 16 mm
33 frames colour
of Fisheries
23 frames colour
of Fisheries
35 frames colour
of Fisheries
40 frames colour
of Fisheries
24. DEEP FRONTIER (AN INTRODUCTION 83 frames colour 12 in record
TO OCEANOGRAPHY) 33 1/3 rpm
Produced by Felton Designer Studio,
1830 Jefferson Place, N.W.,
Washington 6, D.C.
25. FISH AND SHELLFISH OF EASTERN CANADA 106 frames colour
Produced by NFB for Dept. of Fisheries

INDEX TO SUMMARY REPORTS
Sumpry Number f.l.u.
Lobster 1 - 9 1 - 26.
Molluscan shellfish 10 - 27 27 - 52
Groundfish 28 - 44 5'3 - ;93
Herring (Pelagic) 45- 5'6 95' - 12S
Trout 57 - 63 127 - 13?
Salmon 64 - 71 139 - 166
Inshore cod project 72 - 73 167 - 170
Pollution 74 - 81 171 183
Fisheries oceano1raphy 82 -100 185 - 215
Smelt 101 217 - 218-
Mathematical statistics 102 - 105 219 - 227

LOBStER SUMMARIES
Number
Page
The commercial fishery 1 1 - 4
Growth and survival 2 4 - 7
Lobster larvae in
Northumberland Strait 3 7 - 11
Dragging for young lobsters
in Northumberland Strait 4 12 - 13
Cover 5 14 - 16
Survival of lobsters out of water 6 16 - 16
Temperature acclimation 7 16 - 20
Disease 8 20 - 26
Industrial relation:a 9 26

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No. 1
THE COMMERCIAL FISHERY
Lobster
Detailed studies of the commercial fishery have been
conducted annually since 1945 in four areas that differ markedly.
In each of these areas special statistics on catch and effort
have been collected, sample catches have been measured, tagged
and marked lobsters have been liberated and water temperatures
recorded. This report compares the. weight and gross value of
the catch per boat (Fig. 1) and eortsiders the effect of the
exceptionally late spring on the'landi'qgs in the two spring
season areas (Fig. 2}. ·
Gabarus, N.S.
At this port on the outer coast of Cape Breton Island
a 2~-inch carapace size limit has been in effect since 1957.
The season extends from May 16 to July 15. An appreciable part
of the fishery is conducted by dories and skiffs inside the
well protected Gabarus Bay. The average catch per boat in 1961
was only 1,730 pounds with a gross value of $700. As shown in
Figure 1, 90~ of the boats landed less than 3,600 pounds each,
valued at less than $1,400. Sale of 36~ of the catch as
"canners" at 33¢ per pound, rather than as "markets" at 45¢,
was partly responsible for the low gross value.
The spring of 1961 was unusually latee During the
first 6 weeks of the season, bottom water temperatures at 10
fathoms in the Gabarus area averaged 5°1" below the 1956-60
average. Figure 2 shows that the weekly landings did not
approximate the 1956-60 average until the 7th week of the season.
By that time high prices promised fair returns. The season
closed, however, before a normal catch .wa~ made, total landings
being only 45% of the 1956-60 average.
Fourchu. N. S.
The Fourchu area i~ contiguous to the Gabarus grounds.
It is about the same size and has the same fishing season. A
3 3/16-inch carapaee size li~tt has been in effect since 1952.
The area is somewhat more exposed than Gabarus and is fished
by larger but fewer ·boats. · Consequently, the catch per boat is
considerably higll"er than at Gaba:rus. · In 1961, the average
catch per boat' was 4,400 pounds With a gross value of $2,050.
Ten per cent of the fleet caught more than 6,400 pounds per
boat, worth more than • .3 ,000. ; All of the catcp was. sold as
markets at an average price ·of' 46¢. · ·· · · · ··
As at Gabarus, water temperatures and landings were
low during the first 6 weeks but reached normal levels towards
the end of the season (Fig. 2). Total landings for 1961
approxi~ated 62~ of the 1956-60 average.

Lobster - 2 -
I i I I
2 3 4 5 7
Thousands of dollars
Thonsands of
Figure 1. Accumulative percentage distribution of boats
at Gabarus, Fourchu, Miminegash and Port
Maitland according to 1961 landings (pounds
and gross value) per boat.
14

- 3 -
Lobster
50
Fourchu, N.S.
40
/
/
30
-- 1961 //
," --------/
/
/
20
/
/
/
/
/
/
/
/
/
/
/
/
Gabarus, N.S.
30
20
10
1
-_..
-
_..
-
--
/
--
2 3
/
/
/
/
, __
4 5
Weeks
1961
6
7 g
9
Figure 2.
Weekly landings at Gabarus, N.S., and two weekly
landings at Fourchu, N.S., during 1961 season
compared w1 th 1956-60 average.

Lobster - 4 ""
Miminegash. P.Eolo
This area in the northern half of Northumberland
Strait is typical of the small-lobster areas of the southern
Gulf of Sto Lawrenceo The 2-month season extends from August
10 to October 10 and a 2i-inch carapace size limit has been in
effect since 1953o Landings ~er boat in 1961 averaged 3~700
pounds with a gross value of $1~250o The sale of 87% of the
catch as canners at 32¢ per pound partially accounts for the
low gross valueo The landed price for market lobsters in this
area was 48¢o Ten per cent of the fleet caught more than
6,700 pounds per boat, worth over $2,400o
The unusually low water temperatures that prevailed
to the end of July delayed moulting appreciablyo This, in turn,
caused low initial catches during th·~ A1ig:1st J.O tv October 10
season" Total landings at Miminegabh ·: h·:Me·rer ~ were within
10% of the 1956-60 averageo
Port Maitland, NoSo
The 6-month fishing season at this port in southwestern
Nova Scotia extends from December l to l-iay 31 o A
3 3/16-inch carapace size limit has been in effect since 195lo
The fishing grounds extend 8 miles offshore and are unprotectedo
The combination of a long season during bad weather with exposed
fishing grounds extending well offshore necessitates large,
seaworthy~ well equipped boatso Fishing costs accordingly are
higho
Landings per boat during the 1960-61 season averaged
8,000 pounds valued at $4,150o ·Ten per cent of the fleet caught
over 12,300 pounds per boat with a gross value of more than
$6,400o Landed prices for market lobsters during late winter
and early spring were high, raising the season 9 s average to
52¢ per poundo The total catch for 1960-61 was 21% below the
1955-59 averageo
Noo 2
GROWTH AND SURVIVAL
Do
G. Wilder
To determine how fast lobsters grow and how well they
survive in nature, an extensive series of large-scale marking
experiments was started in 1947o One experiment at Gabarus,
No So, was completed this year, another at Port Maitland, No So,
is in progress and a third at Miminegash, PoEolo, has been
startedo
The Gabarus experiment
During the 1958 season, 5,079 lobsters were measured,
marked by drilling 3/16-inch diameter holes through two sections
of the tail fan and liberatedo Tag returns indicated that 447

- 5 ... , Lobster
were recaptured in 1958, l$aving 4pp32 on the grounds for growth
and survival studies. Of these~ lpl79 were recovered during the
1959 season, 374 in 1960 and 75 in 1961. Growth during the
first 2 years has been report~d previQusly. The average carapace
length and weight when released in 1958 and when recovered in
1961 were as follows:
Av. size in 12~8 Av: ~lze in 1261
Car. L. Wei,!{t Ca£,~ L. Weiglit
Shorts 2.6" 0.51 lb 3.5" 1.27 lb
Canners 3.0 0~76 3.8 1.54
Markets 3.4 1.10 4.3 I 2.30
In 3 years the shorts, canners and markets grew 35, 27
and 26% respectively in carapace lengtn and 149, 103 and 109~
in weight. The males grew somewhat rast~r than the females.
The number recovered each year, 'the .estimated number
caught and the estimated survival were as follows:
!22.2 1260 1261
No. of marked recovered 1,179 374 75
% of catch examined . 65.5 56.0 94.6
Estimated catch of marked 1,800 658 79
% of tags returned 41.2 57.8 45.2
Estimated no. of stu•vivors 4,370 1,140 175
% survival · 94.3 44.4 36.3
From the number of marked lobsters recovered, the
fraction of the landings examined and the fraction of the stock
that was caught, as judged by tag returns, the survival from the
end of the 1958 season to the start of the 1959 season was
estimated to be 94.5%. The much lower survival rates during the
next 2 years suggest that the marked·lobsters either moved off
the grounds ·or became more difficult to recognize.
Of the 5,079 marked lobsters' released, the 2,060 that
were below legal size weighed 1J067jpounds. 'Of these, the
fishermen reeaptured 962 pounds (90%) duri~ the next 3 seasons.
For various reasons (marking mortality, movement off grounds,
unrecognizable marks) return~ are almost certainly incomplete.
It would therefore· appear likely that·· slib-legal lobsters in
this area grow.fast enough and survive w$11 enough to justtfy
the present size limit. . . ... . .
The Port Maitland experiment
A total of 9,041 lobsters were sorted into ten size
groups and marked with two *-inch diameter holes in the tail
fan. These were released off Port Maitland, N.S., during April
and May 1960. During the next fishing season (Deoember 1, 1960
to May 31, 1961) a total of 560 were recoveredo The size
distribution of these is shown in the accompanying figure. Many
of the lobsters that were below legal size when marked (Groups
I to..V) did not grow enough to reach legal size and were seldom

Lobster - 6 -
I
II
III
IV
'0 .,
S..
cv
>
0
0
cv
S..
S..
cv
~
~
~
1 v
10 VII
VI
~
10 VIII
10 1--1
IX
Carapace length - inches
Size distribution of 560 marked lobsters recovered off
Port Maitland, N.S., December 1, 1960 to May 31, 1961.
Size range when released in April and May 1960 shown
by~. Non-moulters cross hatched. Size limit of
3 3/16 inches indicated by vertical line.

- 7 - Lobster
landed commercially. Accordingly~ returns from these groups were
low (0.2 to 6.8%) and tend to over-estimate growtho
From the five groups that were above legal size when
marked, 231 were recapturedo Of these~ 106 (46%) had failed to
moulto Few, if any, appeared to have moulted twiceo Growth in
carapace length per moult was remarkably constant in all fiYe
gr. oups » averaging 12. 7%. Because of tll_ e low moulting frequency;
aver~ge growth between marking and rec~ptur• wae only 6o9~.
Since the lobsters that were sub-legal when marked
did not grow enough to be properly represented in.the co~ercial
landings, they cannot be used for survival estimateso Of the
2,116 legal-sized that were marked~ 71 were recaptured in May
1960, leaving 2~045 on the grounds at the close of·that season.
Of these, 231 were recovereq the next seasono Judging from the
part of the catch examined at Port Maitland (97%) and at three
neighbouring ports (4-24%), it is estimated that the fishermen
actually caught 271. Tag returns during the 1960-61 season
indicate that 51% of the stock was caughto This suggests that
only 532 (26%) of the lobsters that were legal when marked
survived to the start of the 1960-61 seasono
In the first 6 weeks of the 1961.-62 season, 92% of
the catch has been examined and only 36 marked lobsters found.
It would appear that o·nly 39 were actually caught o Tag returns
during this period (19.1%) suggest that only 204 marked lobsters
survived to December 1, 1961. We have, as yet 9 no explanation
for this extremely low survival.
The Miminegash experiment
Previous work has indicated that many commercial-sized
lobsters in warm water areas such as Northumberland Strait
moult twice a year. To obtain further information on the
frequency of moulting and on survival in these areas a marking
experiment was started at Miminegash 9 PoEoio From September 15
to October 11, 1961, a total of 8~202 lobsters in ten size .
groups were marked and released, These ranged in carapace
length from 2 1/8 to 3 3/B incheso First recoveries are
expected in August 1962 when a thorough examination of landings
in the Miminegash area will be started.
Noo 3
LOBSTER LARVAE IN NORTHUMBERLAND STRAIT
Do
Go Wilder
The pattern of tows with the lobster larvae plankton
net in Northumberland Strait in 1961 was essentially the same
as in previous years. Five hundred and thirty .. tows were made
between June 24 and September l3o The catch of larvae in each
of the four stages was as follows:

Lobster
Abundance
Stage II
5,687
- 8 =
Stage III
274
Stage IV
106
Total
23ll540
An attempt has been made to establish a more sophisticated
estimate of relative larval ~bundance over the years.
This takes into account the actual length of time the larvae
were in the plankton and the mean length of time spent in each
stage. The former has been taken as the number of days between
the first and last recorded specimens of each stage and the
latter as the time between moults at the mean temperature of
that period. Thus corrected 9 the relative total annual larval
abundancesper unit volume of sea are as followso (Unit volume
in this case is equivalent to a b€'lt of surface water 2 feet
thick covering the area swept during o·.1e ·:_;o~~, i. eo , 12 feet
by approximately! mile.)
% Survival
Stage I Stage II Stage III §tage IV I to IV
1949* 660.9 43.8 14.9 1.4 0.20
1950* 830.4 261.4 69.2 8.4 1.01
1951 516.7 73.4 27.5 8.7 1.67
1952 865.4 180.2 52.4 28.5 3.28
1953* 772.8 82.5 14.8 4.9 0.63
1954* 504.0 39.0 6.1 0.7 0.14
1955* 1,320.7 114.9 27.6 9.6 0.72
1956* 624.7 108.0 40.6 18.2 2.91
1957* 795.4 193.4 J!-9.6 13.2 1.66
1958* 357.3 90.0 44.0 5.8 1.63
1959* 326.2 52.8 7 ..., o

---·- -
Mean catch per drag
1960
Sta~~
I
- 70 t-
i-- - 60 t-
,....
- 50
t-
~r
~ ...
40
,......- 1--
I
30 1"'1--
-
'-rL_
20 t-
I
Ln_ 10
h
--
Stage II
. 40
. 30
~ - 10
.--
JL_L_ r-t _ll
nL
n
...._ ....,
Stage III
4
- 3
- 2
1961
lr
,_--
j
r--
20
rJL
1
Stage IV
2
1
~
rL
n
,ru n_.--
~
~
~_r-1 1. __r-l ~
y
.
Aug. ::sept • uune uu.Ly - Aug. ::sep
Figure lo Weekly abundance of lobster larvae in 1960 and 1961.
-
-
-
-
.
-
\0
t-t
g.
Cl
c:t
• ~

Lobster - 10 -
week's fishing (Septo 10 et seg.) 1st stage larvae were still
present in the plankton (19 per tow) and 4th stage larvae
were more abundant than in any period earlier that season.
This implies that the estimates of 4th stage abundance and
overall survival for 1961 are too low. For years marked * in
the table» 1st and 4th stage abundances may be underestimated,
although the error is not likely to be as great in other years
as in 1961.
The distribution of the catch by stages for 1960 and
1961 is shown in Figure 1.
Distribution
The accumulated data show that differing numbers of
larvae were taken on the different stations» some stations
fishing consistently well» others consistently badly. For
example, Station 2 off Richibucto consistently has high
catches per tow of Stage I larvae and has been "best stationft
on five separate occasions. Station 23 conversely has fished
poorly and has been "worst station" on six separate occasions.
Not all stations fish equally well for each larval stage and
the distribution of the four stages differ. Figure 2 shows
the better stations for 1st and 4th stage larvae based on
analysis of 13 years' data. Stations 2» 3 and 4 show above
average density of both 1st and 4th stage larvae. Differences
in the distribution could be explained by either a variable
survival rate over the whole area, or the larvae being
initially localized and carried bodily by water currents.
Recent drift bottle experiments (Summary No. 83) indicate an
easterly and northerly surface drift across the area. The
1961 larval distribution fits well with this hypothesis
which also infers a southerly drift fairly close to this
section of the New Brunswick coast. This would explain the
pockets of 4th stage larvae which are found in Kouchibouguac
Bay and which were possibly hatched somewhere north of
Escuminac Point in Miramichi Bay. Figure 2 also shows the
larval distribution pattern for 1961.

- 11 -
Lobster
Best
Stage I
@ stations
~ Above ave~ge
stations
Stage IV
•
Larval distribution in 1961
Stage I
Stage II
' . . • • •
Stage IV
.
15
. '
Fig~re 2. Larval distribution based on 13 years' records.
Do Jo Scarratt

Lobster - 12 ~
Noo 4
DRAGGING FOR YOUNG LOBSTERS IN NORTHUMBERLAND STRAIT
The search for early bottom stages was begun in the
fall of 1952 and for several years various types of drags were
comparedo Since 1956, two 4-foot drags working side by side
have been used and the program each year has consisted of a
period of dragging in the spring and another, usually longer,
period in the fallo Between May 24 and June 7~ 1961, 103
drags were made and 640 lobsters taken and from September 18
to November 3, 1961, 1,796 lobsters were taken in 198 drags.
The catch distribution by 1/8-inch size groups is shown in
the accompanying figure. These 1961 catches do nothing to
reverse the opinion stated in last yearvs report that it is
not possible to follow a good or bad year g:.~oup through from
settlement to its appearance L1 the cormnercial fishery.
Abundance of the very smallest stages does~ however, reflect
in some measure the abundance of 4th s~age larvae as
determined by surface towing in the previous years. The
low 4th stage abundance in recent years results in belowaverage
catches of lobsters smaller than 1~-inch carapace
length.
The catches are somewhat biased., but in a manner
that is, as yet, impossible to determine preciselyo It is
obvious from the figure that the drag does not fisH the
smallest lobsters as efficiently as it does larger ones.
The greatest fishing efficiency would appear to be for lobsters
between ll- and 2*-inch carapace length. It is also impossible
to state how efficient the drag is on different types of sea
bed and in any case dragging has been restricted to known
localities where the drag will catch lobsters without being
unduly fouled or caught fast on obstructions. Finally the
stations fished by the two skippers who have done the dragging
since 1956 are not precisely the same. Basically the stations
fall into two groups: a group off Richibucto, N.B.; and
another forming a chain extending southwards close inshore
from Miminegash, P.E.I. Stations in the middle of the strait
tend to be like the Prince Edward Island stations as far as
catch composition is concerned. Analysis of the data from
the past three seasons' operations suggests that the P.E.Io
stations support .. a population·of'somewhat larger lobsters.
The mean carapace length is just below'2'inches and remains
fairly const'ant ·between spririg and· fall drags. The other
group of stations has smaller lobsters and niean carapace
lengths are frequently smaller in spring than in fall {ll
inches against li inches approximately).
The mean size of the total catch in the fall is
fractionally lower than in the spring, although the catch
per drag is somewhat higher. This latter is not constant for
all stations, as some on the P.E.I. side show a reduction in
catch per drag in the fall.

- 13 - Lobster
Sub legal
Legal
[]spring samples
10 .fall samples
0
1 2 3 4
Carapace length - inches
Catch distribution of you-ng lobsters by 1/8-inch size groups.
There could. be several., reasons for these phenomena
·involving··the efficiency of the· 'drag, the biology of the animal
and the effect·of the fishery. Which are important is yet a
matter for speculation. Ideally· it will be necessary to know
precisely, how the drag behav·es .on different grounds and its
relative efficiency incatching di,ff'erent sizee of lobsters.
The~e may only:be resolvable.by direct observation and experimeftt
under water, to which -end a program is .currently being
considered.
Do
J. Scarratt

Lobster - 14 -
No. 5
COVER
The general distribution of lobsters~ operations of
commercial fishermen, results of experimental dragging and
observations made by scuba divers and along the beaches at
low tide all indicate that lobsters are most plentiful on
rocky bottom. In such areas lobsters were almost invariably
found well hidden in individual burrows or crevices beneath
or among large rocks. A typical burrow is shown in Figure 1.
Where possible, it appears that lobsters spend most of their
time under cover, except for relatively brief feeding or
mating excursions. On sandy or muddy bottom~ where no natural
cover is available, lobsters dig shallow saucer-shaped depressions
in proportion to their size. Normally one lobster
occupies each depression. Typical examples are shown in
Figure 2.
The strong tendency for lobsters to remain in
burrows, together with their extreme vulnerability to
predators when moulting and while soft-shelled~ suggests
that cover may be one of the most important factors affecting
the survival of all bottom stages in nature. Suitable cover
might also improve the survival among commercial sizes in
captivity.
To obtain information on the effect of cover on the
survival of lobsters in captivity» a preliminary experiment
was started July 10, 1961. Three lots of 50 one-pound lobsters
with both claws plugged were stored in wooden tanks at the rate
of one pound per square fpot. 'Each lobster in the first lot
was provided with a·tile Ill inches lohg 9 5! inches inside
diameter. Only half tne lobsters in the second lot and none
in the third were provided with tiles. Withih a few minutes
the lobsters occupied the tiles and continued to use them
throughout the experiment, usually emerging only briefly for
feeding or moulting (Fig. 3). The lobsters were e~amined
daily and any found dead were replaced. Every few·aays the
lobsters were fed frozen herring. Moulting (34%) occurred
during the latter half of August and in September. To
February 10 (7 months), only 10% of the lobsters provided ·
with full or half cover died. In contrast» there was a 40%
mortality amo~ those without cover.· In the.tanks with only
1 tile for every 2 lobsters,·· the spaces between the tiles
were usually occupied by individual lobsters~ The low
mortalities in this lot indicate these spaces provided as
effective cover as the tiles.
After this experiment had been in progress 3 months,
the results were considered promising enough to warrant an
initial small-scale test of tiles in nature. On October 18,
24 tiles were set in a line off the Station wharf about 25
feet apart at low tide depths of 1 to 5 fathoms. From then
to November 15 these were observed in situ on six occasions
by Dr. Scarratt and D. E. Graham using scuba. Sea urchins,

Figure 1.
Typical lobster burrow under large
rock. Photographed at 29 feet off
Richibucto, N.B.
Figure 2.
Shallow, saucer-shaped depressions dug by
lobsters in muddy bottom of a Deer Island
pound.
Figure 3.
Usual appearance of 16 one-pound lobsters in
a shallow 4' x 4' tank provided with 16
hollow tiles.

Lobster - 16 -.
sea cucumbers and crabs but no lobsters were observed in or
under the tileso No lobsters W$re seen ip the immediate
vicinity of the tileso This result was not surprising in
view of the general sca·rcity and large size of the lobsters
in this areao Furthertests are.planned for areas where
lobsters are abundant and natural .cover scarceo
No. 6
SURVIVAL OF LOBSTERS OUT OF WATER
D. Go Wilder
Millions of pounds of lobsters are shipped alive to
market each year by the industtyo A knowledge of how long
they can live out of water under controlled conditions provides
a basis by which treatments to extend their survival out of
water can be assessed.
Survl val tests
This year~ survival tests with lobsters from l0°C
water were repeated at o•, 5° and l0°C in moist air (95-100%
relative humidity),. The results from this test and from
previous tests are summarized in Table Io
Table I. Survival times of groups of 50 lobsters from
l0°C water in air at three temperatures.
Test temperature
o•c (1961)
0°C {Previous)
s•c (1961)
5°C (Previous)
l0°C (1961)
l0°C (Previous)
Days to
10% m.ortality
4o5
(5o0p 5o5}
7
(7~ 4o5)
3
{lo5)
Days to
50% mortality
10
(10, l0o5)
11
(;too 5, 8}
8
(3)
The survival times at o• and 5•c are similar. The
lobsters at l0°C survived appreciably longer in the 1961 test.
- .
Effect of feeding
The oxyg~m uptake of recently fed lobsters is
double that of non~fed lobsters and the increase is noticeable
for up to 3 days" Also~ they do not take up oxygen efficiently
when they are out of watero It seems likely that the combination
of these effects would shorten the survival times of
lobsters when they are out of watero The industry knows from
experience that lobsters withstand shipment better if they are
held for 3 or 4 days without foodo Tq determine how great
the effect of feeding may be 9 some recently fed, and others
that had not been fed for 2 to 3 weeks~ were held in air at
5°C. The results are summarized in Table II.

Table IIo
Noo
lobsters
25
25
- i7 - Lobster
Survival times for fed and non-fed lobsters from
l0°C water in air at 5°C (95 to 100% RoHo)o
Days to
10% mortality
Non-fed ~ Diffo
8
10.5
Days to
50% mortality
Non-fed Fed Diff.
The non-fed lobsters survived 1 to 3o5 days longer
than the fed oneso Previous results at l0°C were similaro
A difference of 1 to 2.5 days in survival time was found.
Survival can be extended by withholding food prior to shipment.
Exactly when to stop feeding them before shipment has not been
determined but, on the basis of oxygen uptake 9 3 days is
perhaps a minimum timeo
Survival of lobsters
at increased pressure
Since they do not take up oxygen efficiently when
they are in air, eventual death in air may result from lack
of oxygeno Tests were run to determine whether or not
increased quantities of oxygen obtained by increasing the
pressure (oxygen and nitrogen in proportions normally found
in air] would extend the survival times out of watero The
results of the test at 5°C (95-100% RoHo) are summarized in
Table IIIo
Table IIIo Survival times of lobsters out of water at 5°C
at 1, 2 and 3 times atmospheric pressureo
Noo
lobsters
50
25
25
Pressure
atmospheres
1 (air control)
2
3
Days to
10% mortalitt
10
16
Days to
50% mortality
ll{l0o5, 8}
7o5
ELO
Survival time was not increased by this treatment.
Survival out of water
at vari~s levels of oxygen
Since increased pressure did not increase survival
times, tests at various levels of oxygen were run at normal
atmospheric pressure to determine whether or not increased
quantities of oxygen (oxygen and nitrogen not in normal
proportions found in air} would increase the survival times.
The animals were placed in tight containers and oxygen was
flushed through the containers at different rates to provide
gases containing 50%, 70% and 85% oxygeno The results are
summarized in Table IV.

Lobster - 18 -
Table IV. Survival times of lobsters at 5°C and at 20%,
50%, 70% and 85% oxygen.
No. Oxygen Days to Days to
lobsters content 10~ mortalitz 20~ mortalitz
45 20% (air 6 10
control)
45 50% 5 6.5
45 70f1, 4 7.5
45 85% 4.5 7.5
These treatments with oxygen did not extend the
survival times of lobsters out of water.
Weight loss of
lobsters out of water
Lobsters that have been out of water sometimes
swell when returned to water. This suggests that the salt
concentration of the blood. is increased (increased osmotic
pressure) and water is taken into the animal. Over an 11-
day period out of water at 5°C and 95 to 100% R.H., the
weight loss for 10 lobsters ave~aged 8.4%. About 3% weight
loss occurred within the first 4 days mainly from surface
water drainage. The loss continued at about 0.7%/day and
probablY. represents a loss of water from inside the animal.
The 5.4% weight loss from inside by 11 days amounted to about
35% of the total blood volume. The significance of this
observation in relation to the survival of lobsters is not
yet established.
No. 7
TEMPERATURE ACCLIMATION
D. W. McLeese
When a lobster experiences a sudden increase in
water temperature, the animal warms to the new temperature
in a few minutes and metabolism is speeded up accordingly.
The animal acclimates with prolonged exposure and metabolism
subsides to an intermediate level. · Acclimation involves
complicated physiological changes and the responses of the
animal to the environment are modified. The temparature to
which lobsters are accliJtlated is an important consideration
in studies of their survival and behaviour. Acclimation and
its effect on activity are also important for population
studies since temperature, activity and catchability are
interrelated.
The lethal temperature of lobsters changes in
relation to the temperature to which they are acclimated.
By observing changes in the survival times at a lethal
temperature, it is possible to determine how long it takes
them to become fully acclimated after a change in temperature.

(Hr.
Panel A
- 19 - Lobster
Panel B
10 to 25°C
Test 31°C
20
15
10
(/)
g 5
.c:
0
0
-~ 0
Q)
a
..-1
~
r-i
~
..-1
t 20
::s
(/)
Q) 15
bO
fu 10
>
<
·5
0
0
10 to 20°C
Test 30°C
0
0
40
... 30
20
0
0
10 to l5°C
Test 29°C
10
o~--~~~~--~--~--~--~
15 20 25 30
Acclimation Time in Days
Figure 1. Panel A - Change in average survival time as
lobsters acclimate to a new. higher
temperature.
Panel B - Change in apparent •cclimation temperature
as lobsters acclimate to a new higher
temperature.

Looster - £0 -
When the average survival times reach a different but constant
time, acclimation is judged to be completeo
During this year, the times for lobsters to acclimate
after temperature changes of 5°, 10° and l5°C upwards from l0°C
were determined. These observations completed a planned series
of tests between 10° and 25°C when the animals were exposed to
increases of 5°C (10-15, 15-20, 20-25)p l0°C (10-20, 15-25),
and l5°C (10-25).
Smoothed curves drawn through the average survival
times for each test are shoWn in Panel A of Figure 1. From
these curves, acclimation to l5°C is judged to be completed
by about 10 days (rate 2 days/degree). Acclimation to 20°C
is completed by about 12 days (rate lo2 days/degree).
Acclimation to 25°C is completed by about 12 days (rate 0.8
day/degree). There is little difference in the total times
for lobsters to become acclimated to these temperature changes.
The rates are faster for the larger temperature changes.
The data in their original form provide total ~imes
and average rates of acclimation for t~e particular temperature
changes provided in the experimentso
By interpolation from other mortality data (average
survival times at lethal temperatures in relation to known
acclimation temperatures) the average survival times (Panel
A) have been transformed to the temperatures at which the
lobsters have become acclimated at various test times.
Smoothed curves through these interpolated temperatures are
shown in Panel B for this year's data. Such transformations
enable us to derive times and rates of acclimation for various
temperature increments within the temperature ranges of the
particular experiments.
'
A full understanding of acclimation times and rates
as they are affected by temperature change, general temperature
level and temperature of the surrounding water must await
full analysis of all our acclimation data. However, preliminary
analysis suggests that the rate of acclimation (days/degree)
is primarily determined by the temperature change experienced
by the animal. There does not seem to be a consistent effect
on the rate related to the actual temperature at which the
animal is acclimating. The total times to acclimate to
various temperature changes do not appear to be dependent on
the temperature change or on the surrounding temperature.
D. W. McLeese
DISEASE
At frequent intervals during the year, samples of
lobster blood and mud from lobster pounds were examined for
Gaffkya homari, the causative agent of lobster blood disease.

- 21 - Lobster
Although positive evidence of the disease was found on
several occasions both in commercial and experimental
stocks of lobsters, no serious commercial losses could
definitely be ascribed to the disease. To learn more about
the disease, its development, transmission and possible
cure, a series of experiments were conducted. Shell
disease caused some mortality amongililpounded lobsters.
Preliminary studies of the causative bacteria were
started. ·
Effect of temperature on
development of Gaff'k$-emia
A. Development at S 0 1
10° and 1S°C. Eighteen
tagged and JO untagged healthy lobsters previously
acclimated to so, 10° and lS°C were injected with Gaffkra.
A suspension of Ga[fkya was prepared by, diluting b!ood rom
a diseased lobster With 2.S% saline. og~~ ml of this
suspension, containing approximately 10 viable Gaffkya, was
inoculated into. each lobster.
Blood samples were withdrawn from the tagged
lobsters at definite times after injection to determine by
standard bacteriological methods the number of viable Gaffkya
per volume of blood. Average counts were computed and the
logarithms of these counts were plotted against time in
Figure lA ..
The rate of increase in number of pathogens is
fastest at lS°C, intermediate at l0°C and slowest at S°C.
The curves .resemble the general growth curve for bacteria in
a nutrient broth. All three curves show the exponential
increase; at soc this stage is greatly prolonged.,
The part of the curve that deserves particular
attefition is that where death occurs. In curves plotted for
individual lobsters, the exponential increase is followed by
a more or less horizontal :part before death. The decrease in
rate of multip+ication to Which this part can be attributed
is due to environmental changes in the lobster blood. While
for lS°C this hori~ontal part extends from 4 to 20 days after
infection, it becqmes considerably greater at lower temperatures.
A practical implication of these observations is
that at low temperatures a lobster can be a.disease qarrier
over a very much longer time. Persistence of Gaff'kya during
the winter in lobsters w1 thout considerable mortality is
therefore a distinct possibility. Persistence in the pound
muq should not be overlooked.
Although the 18 tagged lobsters all developed the
disease, not all have died as yet. By 17 days after the
injection all 6 lobsters at lS 0 and 1 lobster at 10° had
died; none of the 6 at so died within that period ..

Lobster - 22 -
6
4
~
4-i
0
s::
0
..-i
+l
tU
M
+l
s::
t)
0
s::
0
0
•
b.O
0
...:I
2
g
6
lA
4
2
0 10
Days after injection
12
14
Figure 1.
Effect of temperature on the development of
blood dis ease.

Lobster
B. Development at 15° and 20°C. A similar
experiment has been carried' out with lobsters acclimated
to 15° and 20°C. Fourteen tagged lobsters were injected
with 1 ml of a suspension of Gaffkyao This suspension was
prepared by harvesting and diluting bacteria from the
surface of a nutrient agar culture. One ml of the suspension
contained approximately 3~000 viable organisms, thus
less was used than in Experiment A.
From Figure lB it can be seen that the rate of
increase in number of pathogens per blood volume is faster
at 20°C than at l5°C. While all 6 lobsters at l5°C developed
the disease, 2 of the 8 lobsters at 20°C were free of Gaffkya
when all others had died. Observations indicate that lobsters
die faster of blood disease at 20°C than at l5°C. Within 14
days after the injection, 6 lobsters which developed the
disease at 20°C died; none of the 6 at l5°C died within that
perfod.
Injection of different numbers
of Gaffkya organisms
A. Five healthy lobsters acclimated to approximately
l3°C were injected with various dilutions of a
suspension of Gaffkya prepared as before from a plate culture.
Blood samples were withdrawn and the logarithms of the numbers
of viable Gaffkya are plotted against time in Figure 2.
Four animals became diseased; 1 animal~ injected
from the highest dilution of the suspensionp recovered after
showing the pathogen·4 days after injection.
B. TWenty healthy lobsters acclimated to approximately
l6°C were injected with various dilutions of Gaffkaa
from a diseased lobster. Blood samples were withdrawn an
evaluated as under A (Table).
Nineteen animals became diseased, th~ one exception
having been injected from the highest dilution of the suspension.
Results of both experiments indicate that the initial
rate of increase i~ concenyrat±on of Gaffkya is faster for
higher doses.
But observations so far indicatethat the initial
difference in rates of increase has rio noticeable effect on
the time to death. It is possible~ however, that such a
relationship would become apparent at lower temperatures.
' ' ' . '
It has been shown that even a small number of
Gaffkya can trigger the disease. Thispwotild suggest that at
least under the conditions of the experiment the"lobster's
defence against infection is weak or absent.
An interesting observation was that in the first
experiment and in temperature experiment Bp the first
appearance of Gaffkya occurred respectively between 1 and 4
days and between 2 and 5 dayso In other experiments,

Lobster - 24 -
GaffkY? was found 6 to 24 hours after injection.
The delay in disease development in the first two
experiments is attributed to the use of Gaffkya from a plate
culture, as in all other experiments the suspension was
prepared from diseased lobster blood. In this connection it
should be mentioned that a weakening by propagatio~ of
Gaffkya on artificial media was suggested by another
.... .!---
4
IV
3
2 -
Concentration
of Gaffkva
inje2ted
Time to
death
1
v
I 4.63 X 105
II n X 10 4
III
n X 10 3
IV n X 10 2
n
X 10
v
13 days
17 n
14
n
16 n
survived
0
2 4
10
after injection
12
14
16
Figure 2.
Effect of concentration of Gaffkya on the
development of blood disease.
investigator who obtained a higher kill when lobsters were
injected with Gaffkya from a diseased lobster.
The few instances, however, where no disease
followed injection of Gaffkya cannot be explained in this way.
Plate counts showed the presence of viable organisms in the
injection samples, even at the lowest dosage, so that the
surviving lobsters definitely were injected with Gaffkya.

- 25 ~ Lobster
Furthermore, one survivor showed a beginning of infection.
Survivors were also found in the temperature experiments.
More of these observations might support the contention that
this is due to acquired resistanceo
Ao Logarithms of average conc~ntrations of Gaffkya in blood
samples after injection With different amounts of
pathogen. The number of lobsters in parentheses.
B. Average days to death after injecti9n ,nth Gaffkya.
Days
after
inje-C'-
N\Ullber of bacteria injected x lo22J
tion 10° 105 104 103 10 2 10 1
A
1 4o01(2) 3.00(3) 2.00(3) 0 (3) 0 (3} 0 (3) 0 (2)
2 5o88{2) 5.10(3) 4.32(3) 3o40(2) 2o30{3) 0 (3) 0 ~2)
3 8.20(2) 7.38(3} 6.35(3) 5o50(2) 4o51(3} 3 0 62 (3) 2.00 2)
B 18.5 10.7 19.3 12.0 9o0 13.7 17.5
Treatment with terramycin
(
Terramycin (oxytetracyclin} is successfully used against
various diseases of humans and animals and also in prevention of
fish diseases. It has been found also to inhibit growth of
Gaffkya,homari in plate cultureso It was decided therefore to
study the effect of this antibiotic on blood-diseased lobsters.
The terramycin used contained 25 g oxytetracyclin HCl
per pound. Preliminary trials against Gaffkya on plate cultures
proved it to be active i~ concentrations ranging from 13 to 666
pg oxytetracyclin per ml.
The general procedure was to infect the lobsters with
Gaffkya and as soon as an appreciable count was obtained in blood
samples withdrawn after injection, to inject 1 ml of a terramycin
solution. Blood samples were withdrawn at intervals to see
whether the treatment had any effect on the disease development.
The animals were each given a single injection of 1 ml
of 2.5~ saline containing 100 to 10,000 pg oxytetracyclin. None
showed any indication that the terramycin had an effect; all
died from gaffkaemia. The few observations show a rate of
mortality which is not appreciably different from that of
untreated lobsters which developed the disease at the same
temperature.
Bathing of diseased lobsters in a 10 to 100~/ml
oxytetracyclin solution for 24 to 48 hours proved to be equally
unsuccessful.

Lobster - 26 ~
Shell disease
Lobsters from a pound in southern Nova Scotia
suffered higher than avera~e winter mortalitieso Of 25
examined in late March, 92% were judged to have shell disease
although less than 10% were heavily infected. Corroded shell
from a diseased lobster was ground in a mortar, suspended in
filtered sea water, and then plated on Hock 9 s chitin medium.
By 7 days, yellowish colonies showed clearance of the medium,
indicating the presence of bacteria capable of digesting
chitin. The bacteria were predominantly long, slender,
straight, gram negative rods. At least two and possibly
three types of colony were recognized~ {1) glistening yellow
with an entire edge, {2} dull brown-yellow with an ill-defined
edge, and {3) dull orange-yellow with an ill-defined edge.
Similar organisms could not be isolated from the sea water in
which diseased lobsters were stored.
J. Demelker
INDUSTRIAL RELATIONS
The industry continues to show a keen interest in
the storage and shipment of live lobsters. Numerous requests
are received for information on the construction of refrigerated
storage units and on suitable formulae for artificial sea water
to store and display live lobsters in inland centres. For
storage along the coast, there is a definite trend away from
floating wooden cars to enclosed storage units containing
numerous shallow wooden tanks supplied with running sea water.
This development has given rise to requests for surveys to
find suitable water, taking into account seasonal, vertical
and horizontal.variations in temperature and salinity. Advice
regarding the construction and arrangement of the tanks, the
flows of water needed and methods of handling the lobsters has
also been sought. · From time· to time·, long established firms
suffer abnormal losses and request a thorough check on their
storage conditions. In one case, this led to a series of
simple experiments to test accumulated sediment in tanks and
nearby bottom deposits for toxicity.
Surveys of tidal pounds to determine the temperature,
salinity and oxygen distribution have shown that the capacity
of such pounds is limited by the supply of oxygen in the bottom
layers during neap tide periods. Blood disease and shell
disease have from time to time given rise to heavy losses and
serious concern. Where possible, samples of water, bottom
mud and lobster blood have been examined routinely to follow
conditions in typical pounds to explain or predict unusual
mortalities. Methods of improving water circulation and
disinfecting such pounds have been discussed with various
operators.
D. G. Wilder

MOLLUSCAN SHELLFISH SUMMARIES
OYSTER (Crassostrea virginica)
Oyster hatchery techniques
Malpeque disease field studies
Growth of resistant and susceptible
spat
Oyster mortalities in Malpeque Bay
Oyster mortalities at Orangedale, N.S.
Hexamita culture studies
Oyster larvae and spatfall, 1961
Conway Narrows changes
South Harbour, N.S., oyster
observations
Hydrographic and meteorological
records at Ellerslie
Oyster briefs
CLAM AND QUAHAUG (Mya arenaria and
Mercenaria mercenaria)
Hydraulic clam rake fishing trials
Quahaug mortalities at Neguac, N.B.
Paralytic shellfish poison studies
SCALLOP (Placopecten magellanicus)
Larval development of sea scallops
Status of the Maritimes scallop fishery
Georges Bank scallop studies
Southern Gulf of St. Lawrence
scallop explorations
Number
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
27
27 - 29
30 - 31
31 - 32
32
33 - 34
34 - 35
35 - 36
36 - 37
37
38 - 39
39 - 41
42 - 43
43 - 46
46 - 47
48 - 49
49 - 50
51 52

No. 10
- 27 - Molluscan shellfish
OYSTER HATCHERY TECHNIQUES
This is regarded as our most important project for
aiding long-term expansion of the oyster industry.
In 1961, we reared oyster larvae in the laboratory for
the first time in Canada. Limited facilities prevented our
handling commercial numbers but we did rear batches of up to
100,000 larvae to setting size and obtained spato
Pilot experiments aimed at developing an artificial food
(suspensions of plant chloroplasts) showed great promise. It is
not certain yet that larvae can grow up on chloroplasts alone but
they do appear to feed on them. Hatqhery oyster larvae are
normally fed on small plants, flagellates 9 the culture of which
is technically difficult. Development of an artificial food would
bring the hatchery process much nearer to being a ~foolproof"
commercial practicability.
We proceeded far enough in other fields to appreciate
some of the difficulties we must face in the future. For
example, when we introduced ready-to-set larvae into tanks
provided with collectors, spatfall was disappointingly low.
This could have been due to a number of factors which need
investigation. Also, growth of spat in our fertilized tanks was
poor, as indeed it was in the ri vero In 1960 9 we achieved very
rapid growth in our tanks, and growth in the river was good too.
Apparently some water condition in the autumn of 1961 adversely
affected spat growth and survival and this was not overcome in
our tanks. This phenomenon has occurred in the river several
times in past years and is obviously of basic importance.
Results to date support our stand that. hatchery techniques are
too immature to justify recommendations to industry.
Further investigations in this field will be a joint
Department of Fisheries-Board project. The Department plans
to build a pilot hatchery early in 1962 for development and
eventually for demonstration purposes. After its initial work
the Board will have a continuing interest in hatcheries not
only for refining techniques but also for exploring the greatest
potential in this field which is selective breeding of desirable
strains of oysters.
No. 11
Spread of disease
MALPEQUE DISEASE FIELD STUDIES
Ro E. Drinnan
Catherine B. Sheldon
There has been no evidence of spread of disease to
unaffected areas where we maintain monitoring trays--Tracadie,
N.So, Bras d'Or Lake and South Harbour 9 Cape Breton.

Molluscan shellfish - 28 ·-
Epidemic at Miscou, N.B.
Mortalities here have proceeded as predicted. Eightytwo
per cent of tray-held natives were dead by the spring of
1961 and this mortality reached 96% by the fallo
Rehabilitation transplants
Tray-held samples of Prince Edward Island oysters
transplanted to the mainland have continued to show low
mortalities.
Mortalities in mainland spat
We now have 2 years' observations on locally-caught
1959 spat in three mainland areas from which to judge the success
or failure of reproduction by rehabilitation transplants.
Cumulative mortalities of these native spat compared with
mortalities among disease-resistant spat introduced from
Bideford and among disease-susceptible spat introduced from
Cape Breton are shown below. All were held on floating trays.
Bideford Origin Cape Breton
Site (resistan!)_ native (susceptible)
Malagash~ N.S. 13 ~4 19o3 91.0
Shippegan, N.B. lln3 30.6 28.3
Mill Creek, N.B. 16.0 3.5 6.5
Bideford ~ PoE. I. 14ol 42.0
From these data we may conclude:
1. Bideford spat have shown the expected normal 5-7%
mortality per year in all areas.
2. We expected mortalities of susceptible Cape Breton
spat to reach 60-90% in all areas but counts show
a variation from 6-90%.
J. It is difficult to interpret the results for native
spat when mortalities among susceptible controls are
so irregular. From the table we can only say that:
(a) Native spat at Malagash are resistant.
(b) All Mill Creek mortalities are sp low that
it is impossible to determine whether the
native spat are susceptibleo
(c) Shippegan spat are no more resistant than
susceptible controls.
However, conditions at Shippegan are complicated. We
have reason to believe that a 20% mortality among native spat
in the first winter was caused by factors other than disease.
Subtracted from the figure in the table, this gives a mortality

- 29 - Molluscan shellfish
due to disease of 10% and this suggests a degree of resistance
at Shippegan similar to that at Malagasho
We feel confident that rehabilitation transplants are
producing resistant young and that these now constitute a
substantial part of the 1959 year-class on the mainlando
Picked mainland spat
Native spat were picked along the shore at Shippegan,
Malagash and Neguac in 1960, and held on trays in their native
areas to observe mortality. They show the following mortalities
to date:
Shippegan
Mala gash
Neguac
Oct. 1960 to Novo 1961
Aug. 1960 tro Novo 1961
Oct. 1960 to Novo i961
75.5%
83.0~
3.3%
The age of these spat cannot be determined accurately
but 1957, 1958 and 1959 are the most likely year-classes
represented. It is not surprising then that they have shown high
mortalities at Malagash and Shippegan. The low figure at Neguac
is encouraging.
follo~ling
Malagash
Upper Caraquet
Poirier's Shore
{Caraquet)
Neguac
More such trays were set up in 1961 and have shown the
mortalities:
Sept. to Novo 1961
Sept. to Nov. 1961
Sept. to Nov. 1961
July to Nov. 1961
0.2%
10.6%
5.3%
1.8%
The heavy losses at Caraquet in such a short period
suggest that these stocks still contain a high proportion of
susceptibles. ·The figures from Malagash suggest that many of the
susceptibles in thesestocks have died out since 1960 and that
recovery is under way. The N~guac picture continues bright.
Outlook
The variable mortalities among susceptible Cape Breton
spat in these mainland areas may be ascribed to a change in the
condition of the disease from epidemic to endemic. Regardless
of how they are explained, they make interpretation of results
difficult. Nevertheless, on balance~ there are encouraging
signs of recovery of the mainland stockso
We are still unable to explain the lag in production
of disease-resistant spat in the rehabilitated areas (1958 spat
were susceptible and died). We have studied and discarded one
possible explanation (see Summary No. 20)o
R. E. Drinnan
E. Bo Henderson

Molluscan shellfish - 30 -
No. 12
GROWTH OF RESISTANT AND SUSCEPTIBLE SPAT
In 1961 samples of 100 each of native spat (disease
tolerance unknownJ, of Bideford spat {disease-resistant) and of
Orangedale spat (disease-susceptible)~ all of the 1959 yearclass~
were placed in separate trays at the Department of
Fisheries Oyster Culture Stations at Malagash, NoS., and
Shippegan, NoBo The purpose was to see whether disease affected
grqwth and whether growth rate could be used as an indicator of
disease resistance or susceptibility. For comparison, similar
samples of 1959 Orangedale spa:t were held at Orangedale and at
Bideford and 1959 Bideford spat were held at Bideford. The
length of the shells of these oysters was measured monthly from
June to November.
Length growth
All groups showed peak growth in August and September.
At Malagash and at Shippegan the native spat grew
approximately as much as Bideford spat held in these areas;
whereas~ the Orangedale spat, which were apparently diseaseaffected,
showed only 60% of this growtho
Shippegan is generally considered a slow-growing area
but spat growth there approached that at Bideford. This may
have been due to the unusually warm summer of 1961.
At Orangedale, the Orangedale spat grew vigorously-­
better than any spat anywhere else.
Weight increments
At Bideford, a more intensj.ve June-to-November study
was made of 50 Bideford and 50 Orangedale spato These were
weighed under water at 2-week intervals to test the utility of
such measurements in detecting diseased oysters (Annual Report
1960-61, Summary No. 21).
'l'he peak shell weight increment occurred in August and
early September, coinciding with the peak linear shell growth.
On the average the weight of resistant Bideford spat increased
approximately twice as much as that of the susceptible Orangedale
group but some of the latter grew very well. The difference in
variability between these groups was very marked. The coefficient
of variation (100 s/x) of the resistant group varied from 30 to
50. That of the susceptible group was in this range until August,
then rose sharply to over lOOo This value was maintained through
the remainder of the growth periodo
Increments for individual susceptible spat showed no
correlation with mortality, however. Oysters which died had
often shown good growth up to the time of death and oysters
which showed poor growth often failed to die.

- 31 - Molluscan shellfish
This anomaly and the entire field of the effects of
Malpeque disease on oysters merit further investigationo
No. 13
Central Malpegue Bay
OYSTER-MORTALITIES IN MALPEQUE BAY
Ro Eo Drinnan
Eo Bo Henderson
High mortalities in native oysters occurred in the
central bay up to and including the winter 195B-59o Since then,
mortalities in both native and introduced oysters have been
within the normal range.
Native oysters, however~ have been consistently
thinner than the introduced oysterso Th.is difference was shown
again in early 1961 but both groups showed a steady decline in
fatness through the year and are thinner now than we have ever
seen them before.
In the past, the thinness o.f the natives has been
associated with large numbers of small ,.flatworms on the gillso
We thought these competed with the oysters for food and
p~evented fattening. Up to 1961~ these worms were found only
in natives. In 1961, however» worms were abundant in both
native and introduced oysters and may have contributed to the
steady decline in fatness.
Heretofore our small plantings of i.ntroduced oysters
showed neither mortality nor loss o.f fatness and we concluded
that the cause was no longer acting and that reseeding would
have a reasonable chance of successo The 1961 observations
obscure the picture. We do not know but should know what
would be the effect of la~ge-scale introductionso
We are continuing tray observations to follow the
trends seen in 1961 but the central bay area is too open and
difficult of access to allow intensive samplingo In 1962, we
plan to extend our observations to a more readily accessible
bed.
Bideford Narrows
There was an estimated 30 to 40% mortality in this
area during the winter 1958-59 but no mortalities have been
observed here since our tray observations were begun in 1959.
At that time we set up trays like those in central Malpeque
Bay, comparing native and introduced oysterso
During 1959 and 1960, the native oysters were
markedly thinner than introduced stock and showed much higher
(about four times) worm countso In 1961, the worm counts were
low and similar in the two groupso Native oysters were thinner
than the introduced stock but the difference w~s smallo

Molluscan shellfish - 32 -
Conclusions
The cause of mortalities in these two areas is not
clear because most of our observations have been made since
the mortalities occurred.
High worm count may be responsible for thinness of
native oysters and in former years this may have caused overwinter
deaths from starvation.
There is some evidence that mortalities of this kind
occur frequently in Malpeque Bay and may become very important
with intense oyster culture. We plan to initiate long-term
monitoring (oyster mortalities and worm counts) in a number of
local areas including at least one with heavy worm infestation.
No. 14
OYSTER MORTALITIES AT ORANGEDALE~
R. E. Drinnan
E. B. Henderson
B. T. Khouw
N.S.
Annual mortalities in oysters at the Department of
Fisheries Oyster Culture Station at Orangedale in the Bras d'Or
Lake~ Nova Scotia, have increased in recent years. Their extent
and other characteristics appear in our data from ten year~
classes, including many thousands of oysters held on trays at
the surface and on the bottom. There is much variability from
season to season and from group to group but some trends have
emergedo
The annual mortality has increased steadily from 5%
in 1956 to 30% in 1961. There are two clear peaks, one in
spring (May~Jurte) and one in late summer (August-September).
There is no consistent variation of mortality with age.
The causes of this mortality are obscure. Mudblister
worms (see Summary No. 20}, though prevalent here, are
not likely responsible. Histological examination of live and
gaping oysters gives no indication of disease. Low salinities
in spring correlate well with the spring mortalities in years
where we have complete salinity records and may be an important
factor. But we can suggest no cause for the summer mortality.
R. E. Drinnan
E. B. Henderson

Noo 15
- 33 - Molluscan shellfish
HEXAMITA CULTURE STUDIES
Hexamita is a min~te protozoan that has been suspected
of killing oysters and even of being the causative agent of
Malpeque disease. A method of pure culture (axenic) of the freeswimming
form (trophozoite) of Hexamita has been developed and
perfectedo With the aid of antibiotics and the maintenance of
a comparatively low oxidation/reduction potential in the medium,
the trophozoites can be isolated and maintained in pure culture.
Having achieved this, we hope to study their biology and
suspected damaging effects on oysterso
Studies of trophozoite popul~tion growth in axenic
cultures show that densities of 2 x lObjml are reached within
4 weeks of incubation at 4°C. or within 14 days at room temperature
(18-20°C)o Growth is exponentialo An initial lag phase
is usually observed (48 hours at room temperature and somewhat
longer at 4°C). The trophozoites tolerate a wide pH range with
the optimum at pH 6.0 to 7o5o Growth is possible at the extremes
of the optimal pH range with the appearance of some spherical
stages with intact flagellation and~ often 9 cyst formation.
Growth at room temperature has only recently been
achieved. This was due partly to our failure to provide
Ca-pantothenate (vitamin s 5
). Apparently trophozoites can
synthesize pantothenate at 4°C but not at room temperature.
This is consistent with the fact that they are abundant in dying
oysters in summer when water temperature often reaches 25°C.
A study of carbohydrate metabolism of trophozoites in
culture has begun. Glucose, mannose and maltose are utilized
with acid production. Hydrogen sulfide is produced and often
renders cultures black due to precipitation of FeSo No indol
has been detected. The primary substrate for growth seems to
be the phospholipids of the egg yolk which is an ingredient of
the culture medium. Cultures grown with lecithin instead of
egg yolk suspension do not survive over three transferso
However, the possible involvement of other phospholipids as
growth substrates deserves further investigationo It would be
desirable to study the phospholipid content of oysters for a
fuller understanding of the nature of Hexamita parasitization.
It is known that phospholipid content of the oyster increases
in winter, and this is the tfme when Hexamita· is abundant in
oyster tissues. - · ··
The possibility of a schizont {when reproduction is
by simple cell division) stage in the life cycle of Hexamita· has
also been explored. Many in vitro attempts to induce trophozoites
or cysts to undergo schizogony have failedo This failure
may be due to an incomplete understanding of the necessary
cultural conditions. Further attempts will be madeo

Molluscan shellfish - 34 =
A method of counting trophozoites of Hexamita in oysters,
involving trypsinization, has been developed, Its usefulness for
making seasonal counts in live oysters is under trial.
No. 16
OYSTER LARVAE AND SPATFALL 1961
B. T. Khouw
As a service to tpe Department of Fisheries and industry,
we regularly make spatfall predictions and monitor spatfall in
several areas" This year all samples of oyster larvae were
obtained by straining measured volumes of water from a motordriven
pump. At Ellerslie these observations are part of a
larger~ long-term program designed to provide information on
the dynamics and behaviour of larval populations and their
relations to subsequent spatfall.
At Ellerslie, spawning was late~ the first larvae
being recorded on July 10. The maximum concentration was
4,500/100 L.--modest in comparison with years of heavy spatfall
like 1959 and 1960. There were distinct broods of larvae f~om
two spawnings July 10 to August 1 and August 5 to 17.
Bideford River was the only area which yielded
sufficient larvae for prediction of spatfall. The spatfall was
light in comparison with the numbers of larvae seen--especially
the set from the second brood--indicating a heavy larval
mortality. The larvae matured rapidly and the spatfall began
on July 28 in advance of the predicted date. It continued to
August 29 with a major peak August 3 to 5 and a lesser peak
August 25 to 28.
The course of spatfall was followed in all areas by
counting the newly-settled spat (gross catch} on individual
scallop shells renewed daily at Ellerslie and weekly in other
areas. In all areas the net catch (comn1ercially useful spat
in late autumn) was counted on commercial egg-crate filler
collectors. The data are summarized below:
Location
Ellerslie~
P.E.I.
Pred.
First
date of First peak of
spatfall spatfall spatfall Max. catch Net catch 2
__ l~s=h~e=l=l~ /filler /in.
Bideford River Aug. 2 July 28 Aug. 5 367/day 20 0.03
Paugh v s Creek - 216 0.3
Shippegan~ N.B. Aug. 2 Aug. 4 1/2 wk 0 95 0.1
Malagash, N.S.
"
July 18 July 18 11/2 wk. 75 0.1
Gillis Cove~ N.S. " July 6 Aug. 3 254/2 wk. 273 0.4
Crowdis Bridge, N.S." June 23 July 27 8/2 wk.

- 35 = Molluscan shellfish
At Ellerslie the overall spatfall was good but poor
survival and growth reduced tnis in Bideford River to a moderate
net catch of medium-sized ·spato In the tributary Paugh's Creek,
conaitions improved in the fall to give a heavier net catch of
larger spato
In the other areas the timing of spatfall was very
variable and, in general, light to moderateo Gillis Cove
produced the heaviest net catch in 196lo The yield at Shippegan
though light by general standards was the heaviest seen there
for many yearso
As in 196o (Annual Report 1960-61~ Summary Noo 16),
trial lots of scallop shell strings~ bags of oyster shells and
loose shells of scallops, oysters and mussels were laid on
polyethylene sheeting spread on the bottom in the intertidal
zone in Bidefordo They all caughi,j spat but the shell strings
worked besto They remained free of fouling organisms and
November counts at one station showed a net set of 13 spat per
shello The Department of Fisheries plans a commercial-scale
test of spat collection with shell st~ings in the intertidal
zone in 1962o
Noo 17
CONWAY NARROWS CHANGES
Ro Eo Drinnan
So Eo Vass
W. Bo Stallworthy
Jo Co Medcof
In 1958 and 1959, when the first large-scale spat
plantings were made on the Conway Narrow~ reserve~ we made a
survey of the area. This was intended to provide a baseline
from which any changes due to spat plantings or ~ffecting them
could be measuredo It included observations of eel-grass
cover, bottom soil-conditions, water temperature and circulation,
winter ice conditions and other animals present--especially
possible oyster. pr~d~to~~ or competitors 0
Since this time so!lle ch2m~es hav~ taken plac~ as
shown by a 1961 surveyo -
Eel-grasso There has been a fourfold increase in
density and a slight increase in shoot length of eel-grass
plantso As a result, spat harvesting had to be carried out by
hand raking in 1961.
Predators and competitorso Mussels are more numerous
and rock crabs less so, but starfish are still rareo
Bottom conditionso The bottom is softer, especially
in the area of the earliest plantingso Here an inch or two of
soft black mud has altered shell shape of oysters from
predominantly "fancy" in 1958 to predominantly "standard" in

Molluscan shellfish - 36 =
196lo In planning future utilization of this area, this change
will be an important factor to consider.
Oyster condition. An autumn decrease in the fatness
of oysters on the reserve was noted in 1960 and again in 1961.
Causes of changes. Lagoons such as the Narrows behind
offshore bars are often unstable and at first we thought that
the observed changes were part of an evolutionary process in
lagoon structure. However, preliminary comparison of aerial
photographs of this area taken in 1935 and 1958 shows no changes
that would support this conjectureo
The increase in eel-grass seems to be part of a widespread
up-surge of this plant all over the Maritimes in recent
years. The softening of the bottom seems to have been caused
by the deposition of oyster faeces~ aided perhaps by the heavy
eel-grasso Changes in the mussel and crab populations are
probably associated with the presence of oysters and the
increase of eel-grass.
All observations point to food shortage as the
explanation for thinness of the oysters" Oysters held on trays
in the Narrows and therefore under better feeding conditions,
were fatter in 1961 than those on bottom, and oysters moved
from the reserve to floating trays in Bideford River doubled
their fatness in 2 to 3 weeks. Hydrographic observations show
that the water over the reserve is oceanic in origin and
relatively poor in nutrients and oyster food,, Apparently we
have already planted the reserve with more oysters than its
food supply can support.
The Department and Board are developing a joint
program to tackle the reservevs three major problems:
(a} increase in eel-grass;
(b) increase in softness of bottom;
(c) limited food supplyo
Part of this program will be carried out in 1962,
some aspects have already begunp but much of the work requires
more elaborate preparation.
Noo 18
SOUTH HARBOUR, N.So 9
OYSTER OBSERVATIONS
R. E. Drinnan
In 1960, oysters in this area became very thin in
the fall and held poorly in storageo We were asked to look
into the situation. The thinness was associated with low
salinities, a result of run-off and poor water exchange with
the open seao

- 37 = Molluscan shellfish
In 1961, the oysters remained thin throughout the
year and experienced a 30% mortality in September and Octobero
But salinity was high through Octobero Histological examination
of' oysters during the mortality gave no suggestion of'
disease but showed a virtual absence of' food reserveso
It is suggested that the thinhess of' oysters and the
mortality were due to poor feeding conditionso This underlines
the need for the projected joint Department-Board study
of' the practicability of' fertilizing certain estuarine areas
to increase oyster :food production~
Noo 19
Ro E. Drinnan
Eo Bo Henderson
HYDROGRAPHIC AND METEOROLOGICAL RECORDS AT ELLERSLIE
Many hydrographic and meteoro~ogical data have been
collected in the 30 years of' existence of' the Sub-Station at
Ellerslie~ P.Eoi. An analysis of these is now under way. The
purpose is to describe variations in such factors as water.
temperature and salinity, rainfall and sunshine a Initially»
we are searching for combinations of' factors important in spat
production which might allow forecasting of' good apat yearso
But such descriptions will be of' great value in many long-term
studies of' oyster biology.
We have relatively few data on winter hydrography at
Ellerslie but we are beginning to realize the importance of'
this season to oysters. Last winter (1960-61) we initiated a
program of winter hydrography and expanded it this winter
(1961-62) 0
Hydrographic conditions in 1961
Water tempetatures fell steadily in the late fall of'
1960 and on November 25 reached 3°C» the temperature below
which oysters remain completely close~L Ice cover was
established on December 9 apd increased steadily in thickness
through January and February 1961 ~ reaching a ma.ximu:Ql of' 34 to
39 incheso The break-up occurred on May 4 at which time, due
to the heavy run-off, a freshwater layer was established at
the surfaceo This persisted until May 16» reaching its maximum
thickness of 6.5 feet on May lOa Water temperatures rose above
3°C on May 14o
Thus during the winter of' 1960-61, oysters experienced
170 days below 3°C, 30 to 40 days longer than normalo
After May 14, water temperatures rose slowly through
May and June and reached 20°Cp the minimum spawning temperature,
on July llo Temperatures remained above 20°C until September 12
and then fell~ reaching )°C on December lOo Ice cover was
established on December 17o
So E. Vass

Molluscan shellfish ... 38 -
Noo 20
OYSTER BRIEFS
Polydora infestation of oysters
at Orangedale, N.S.
Oyster mortalities at Orangedale (see Summary No. 14}
have been heavy and fishermen have claimed that mud-blister
worms were responsible. We therefore made a survey of mudblister
worms (Polydora) infestations in a number of the local
stocks and compared results with those of a similar survey in
1939o
The percentage of oysters infected has increased
since 1939 but it is doubtful that Polydora has changed its
role in oyster mortalities. It may kill some oysters, especially
if its blisters are located in the vicinity of the adductor
muscle. However, it is very unlikely that this has contributed
significantly to the present mortality"
The study showed that the percentage of oysters
infested increases with age; tray oysters are as heavily
infested as those on the bottom and the distribution of
blisters in the shell is very localized. These points will be
further investigated to establish the importance of this animal
to our oyster fishery.
The sex ratio. in oysters
E. B. Henderson
The classical description of the sex ratio in American
oysters is of a predominantly male population in the first years
of spawning becoming predominantly female later in life with a
change in sex by individuals. Observations in Canada in the
1930vs suggested a 1:1 ratio in the second summer after setting,
the proportion of females increasing after this to 70 to 80% at
5 years old.
In 196o, a hypothesis was erected on the basis of
this concept of sex change to explain the disease susceptibility
of the 1958 year-class which was produced in New Brunswick and
Nova Scotia areas that received rehabilitation transfers in
1957. It was suggested that these spat were crosses between
the large~ predominantly female oysters of the disease-resistant
rehabilitation transplants from Prince Edward Island and the
small 9 predominantly male, susceptible 7 wild~ native spat, this
cross being susceptible.
In 1961, gonad smears of oysters of these groups were
examined to test the validity of this hypothesis. It was
found that 80% of the small natives were female, while the
ratio 9 male to female, in the transplanted oysters was
approximately 1:1. This not only made the hypothesis
completely untenable but was sufficiently unexpected to merit
further investigation of the sex ratio generally.

- 39 - Molluscan shellfish
Over 1,500 oysters were examined, ranging in age from
one to an estimated 12 years. The results suggest a predominance
of males in the first 2 years of life falling to a ratio
of 1:1 in the third year and a maintenance of this ratio up to
12 years. The results from individual samples are very variable
and it is likely that such local factors as abundance of food
are important.
No. 21
HYDRAULIC CLAM RAKE FISHING TRIALS
R. E. Drinnan
Austina V. Kennedy
This project was undertaken in 1960 with financial
support from the Industrial Development Service of the Department
of Fisheries {Annual Report 1960-61, Summary No. 26) but
was continued in 1961 at Fisheries Research Board expense.
The same pump-engine assembly and manifold were used
but minor changes were made in the rake to facilitate fishing
operations. The discharge hose was attached directly to the
manifold and a "D" type steel handle fastened to the opposite
side. Four sets of nozzles 2, 3, 7 and 9 inches long were made
to determine the effects of nozzle length on fishing efficiency,
rate of fishing and damage to marketable and non-marketable
sizes of clams.
The trials were carried out at Clam Harbour, N.S.,
where similar tests were made with M.B. Cyprina and the
hydraulic escalator harvester in 1956 and 1958. This
particular flat is composed of pure sand and contains a
scattered population of clams. Twenty-four plots, 3 feet by
10 feet, were set up and planted at a density of 9 per square
foot with commercial-sized clams of 1~ inches mean length.
Each plot was run through once with the hydraulic rake while
the flat was covered with 2 to 3 feet of water. Each set of
nozzles was tested on several plots. The 2-inch nozzles just
touched the surface of the soil but the 3-, 7- and 9-inch
nozzles penetrated 1, 5 and 7 inches respectively into the
soil and slowed up the fishing rate proportionately. The
tidal run-off in Clam Harbour is so slow that the clams
brought to the surface of the soil by the hydraulic rake had
to be gathered with .a hand rake or they buried themselves
before the tide fell low enough to expose the flats.
If the hydraulic rake were 100% efficient in taking
clams in its 2-foot by 10-foot path, it should harvest 180
clams from each plot. This was the criterion on which we
estimated in considering the clam recovery data. Some of the
results are shown in the following table:

Molluscan shellfish - 40 -
Mild Steel
I l.~~
2
3u
4 Axle
2 11 D. Fire Hose
Couplino
'--+111----+--+-- Reducino Couplino
'-----:-'-'=~~--- ~ 11 X 2 11 N o z z I e
! II tO .! II
2 8
Perspective drawing of hydraulic rake designed for fishing
soft-shell clams. A 6 h.p. engine powering a 2-inch x 2-inch
centrifugal force pump delivers about 130 gallons per minute
at a pressure of 25 pounds per square inch to the nozzles on
the manifold. The jets of water apparently form an emulsion
with the soil which stratifies as it settles, the heavier
particles first. Since the specific gravity of clams is low,
they are found on the surface of the soil after the rake
passes. The complete unit, less the dinghy which floats the
pump assembly, costs about $500.
(Drawing P.W.G. McMullen)

- 41 =
Molluscan shellfish
Fishing trials with hydraulic clam rake
Clam
Nozzle Fishing rate recovery Breakage
length ftLmin.
-~ ~
" " -
2" 10 - 20 96 3
3" 15 - 20 92 7
7" 9 ao 12
9" 5 90 10
Other tests were made with the hydraulic rake to
determine the scatter pattern of clams that are too small to
be of commercial use. For this purpose~ two 3-foot by 10-foot
plots of formalin-killed clams 1 inch in length were planted
9 per square foot and fished in the same way as the plot of
large, living clams except that they were gathered when the
flat was exposed at the following low tide. The results
showed that 60% were left on the soft soil of the digger
track and 40% were on the undisturbed flat and spread for a
distance of 100 feet down tide from the plotso Breakage
was negligible--less than 2%o When this same treatment was
applied to two similar plots of small living clams, only 5%
of the clams in the path of the digger remained on the
surface of the soil at the following low tideo No breakage
was observed.
The trials show that the hydraulic rake with 2-inch
nozzles is a manoeuverable and eff'icient tool for harvesting
soft-shell clams. It fishes rapidly 9 covering about 30 square
feet per minute; harvests, in sandy soil~ 95% of the marketable
clams in its path; damages less than 5% of the marketable clams
and destroys only about 1% of the small clams left behind in
the soil. In contrast, a fisherman with a clam fork covers
about 5 square feet per minute; gathers 60% of the marketable
clams in the soil he turns; breaks 10 to 15% of the clams he
harvests and smothers or otherwise destroys 50% of the small
clams he leaves behind. It seems more than likely that we
would have better yields from our clam stocks if we were to
adopt the hydraulic rake in preference to the clam fork.
We believe there are improvements that could be made
in the hydraulic rake by further work but we feel we have done
enough to demonstrate its potentialities and its likely effects
on clam stocks. If the Department should approve areas where
the hydraulic rake may be used, clam fishermen will find their
own ways of improving and adapting it to suit the soil conditions
in which they are workingo We propose closing off the
studyo
J o S. MacPhail

Molluscan shellfish - 42 =
Noo 22
QUAHAUG MORTALITIES AT NEGUAC 9
NoB.
Observations have continued on mortalities of Neguac
quahaugs on the Hay Island bed. Our earlier report (Annual
Report 1960-61, Summary No. 13) of mortalities in quahaugs
transplanted to this bed has been confirmed. Tray samples
of stock transplanted from Malpec to this bed showed a total
mortality of 76% between November 1960 and November 1961.
This is very similar to the 89% mortality in Hay Island natives
between November 1959 and November 1960.
Until this year Malpec~ the nearby source of the small
quahaugs used in the transplants, showed much lower mortalities
than Hay Island and we assumed that the cause of the mortality
was not present. But Malpec quahaugs showed a 100% mortality
in 75 days' cold air storage (October 1961 to January 1962).
This contrasts with no mortality in the same stock in 72 days'
storage in the winter 1959-600 High storage mortality was
the first symptom of the Hay Island quahaug epidemic and
these observations suggest that Malpec may now be affected.
If this is the case, we can expect a 90% mortality in 1962.
Examination of fresh and fixed Neguac quahaugs has
outlined the development of symptoms of the mortality and shown
a number of parasites. Dead and dying Hay Island quahaugs
showed extensive tissue damage to the heart, kidney and gills.
The blood is often heavily infected with bacteria, many of which
are probably secondary. Weak and newly dead quahaugs showed
loose aggregations of one type of bacterium in the musculature
of the foot. Though not seep in the live quahaugs, it may be
truly parasitic. ·
A chytrid fungus, Olpidium, was found in 50% of
Hay Island gapers--typically in the gill and kidney but
occasionally in connective tissue of the guto It was also seen
in 15% of live Hay Island quahaugs and is undoubtedly a true
parasite. Until the recent mortality in air storage, all
Malpec quahaugs were negative for Olpidium. But among the
few examined since, tw~ have been positive.
Another parasite, believed to be a bacterium, occurs
in a high percentage of live quahaugs from both Hay Island and
the Malpec. Its aggregations form basophilic sacs in the·
ciliated cells of the gill tissue. It is unlikely that they
have any relation to the mortality.
None of the parasitic forms seen to date occurs
consistently enough to be responsible for the mortality on its
own. Possibly the high density of these quahaug populations
has encouraged increases in all parasiteso If this is true,
such epidemics might be prevented by controlling the density
of the stocks.

- 43 - Molluscan shellfish
No. 23
PARALYTIC SHELLFISH POISON STUDIES
Annual recurrence of paralytic poison in shellfish in
the Bay of Fundy and the estuary of the Sto Lawrence has aroused
concern among public health and fisheries agencies and they have
recognized the need for a more efficient system of monitoring
and predicting danger periodso Last year~s analysis of earliE!l"
toxicity records (Annual Report 1960-61~ Summary Noo 10) gave
direction to our 1961-62 program which involved traci~ the
actual source of poison in shellfish and determination of
environmental facto.rs that regulate annual build-up of toxicity
levels in particular areas. This program is being pursued in
collaboration with the Department of Fisheries and the Department
of National Health and Welfareo
Bay of Fundy shellfish toxicity
trends 1961
1961 was a year of moderately high toxicity on the
Nova Scotia as well as on the New Brunswick side of the Bay of
FUhdy and at least six persons were taken ill due to consumption
of poisonous shellfisho Toxin titres started building up
in most areas from the second week of June when water temperature
was around 7°C. However~ peak scores in shellfish were
recorded during late July and early August when water temperature
was over l0°C. At Lepreau Basin which retained significant
scores throughout the year~ a second lesser peak was
observed in clams and mussels during late October (Table).
In most places mussels were more toxic than soft-shell clams
but after September this situation was reversed at Lepreau
Basin, Where clams retained more poison than mussels.
Individual variations in toxicity levels were
noticed within and between species of shellfisho As a rule,
mussels had a higher poison content than soft-shell clams;
bar clams accumulated five to ten times as much poison as
soft-shell clams and musselso
Plankton reconnaissance
For years there has been circumstantial evidence that
Bay of Fundy shellfish derive their toxin from feeding on the
planktonic dinoflagellate, Gonyaulax tamarensiso Efforts were
therefore directed towards obtaining a definite picture of the

Molluscan shellfish - 44 ~
relationship between the abundance of Gonyaulax and levels of
toxicity. Regular plankton hauls have·been·made at Head
Harbour, N.B., since January 1961 and studied for species
composition. First appearance of Gonyaulax as an ~occasional~
plankter was noticed in the second week of June. Its subsequent
abundance in July and August coincided with the rise in mussel
toxicity at Head Harbour as well as with poison content in
plankton extracts (Table}. During this period of peak toxicity,
surface water temP.erature at "Prince" Station No. 5 was ll.l°C
and salinity 31.3%o. No dinoflagellates were noticed in plankton
samples after August. Large ciliates {Favella) which feed on
Gonyaulax were very common in September and may have been
responsible for its disappearance.
Plankton nets coarser than No. 25 silk have been found
unsuitable for Gonyaulax collection. Techniques for preparing
extracts of plankton concentrates by "acid hydrolysis" have been
standardized and these extracts are subjected to the same type
of bioassay as is used for extracts of shellfish.
Culturing Fundy Gonyaulax
Much effort was devoted to setting up laboratory
facilities for culturing dinoflagellates in artificial and
enriched media. Successful isolation of Gonyaulax from Head
Harbour plankton was accomplished in July and only recently it
has been possible to maintain healthy unialgal cultures in the
laboratory. These cultures are thriving at 10 ~ l°C in a
temperature-controlled room under constant illumination {400-
500 ft.c.) provided·by banks of 40-watt cool fluorescent lamps.
Of nine enriched marine media tested, only "Erd­
SCHREIBER" and ASP7 {Provasoli) have sup~orted ~ood growth and
population densities as high as 2.5 x lOJ cells(ml have been
obtained within 4 weeks after inoculation. Mass cultures of
Fundy Gonyaulax are being maintained in 1 to 5 litre flasks for
special studies.
We have. also been able to maintain unialgal cultures
of Gonyaulax tamarensis from Plymouth, U.K.» using stock
cultures supplied by the Haskins Laboratories 9 New York, U.S.A.
Experimental observations
Bioassays of extracts of Gonyaulax cells concentrated
from the cultures by microfilteration have scored as high as
123 micrograms. And when pure cultures {population density
1.9 x 104 cells/ml) were fed to non-toxic clams (Mya), they
became toxic. There is no doubt now that Gonyaulax is the real
source of paralytic shellfish poison in the Fundy area.
Earlier, the Fundy form was identified as G. tamarensis
but there are reasons to believe that it might be a different
species or possibly a different strain of the same species. One
reason is that cultures of Plymouth form have shown no toxicity
whatsoever. Mr. Adam Bursa of the Arctic Unit has undertaken
taxonomic studies on Fundy Gonyaulax.

- 45 ... Molluscan shellfish
Shellfish and plankton toxicity scores from typical affected
areas as related to the abundance of Gonyaulax in 1961. Toxin
scores for shellfish are given in ).lg/100 g of meat. Those for
plankton are based on the catch from 15-minute horizontal tows.
Month
I
Jan.
Febo
Maro
Apr.
May
June
July
Sept.
Oct.
Nov.
Dec.
Halfmonth
period
1st
2nd
1st
2nd
1st
2nd
1st
2n4
1st
2nd
1st
2nd
1st
2nd
lst
2nd
1st
2nd
1st
2nd
lst
2nd
1st
2nd
Heaa Harbour
(Mytilus}
< 32
< ).2
32
40
56
36
451
3280
1944
299
168
68
45
34
33

Molluscan shellfish - 46 =
Experiments to determine the thermal~ photic and
nutritional requirements of Fundy Gonyaulax are in progress.
Additional studies on growth kinetics in relation to the
various environmental Cbnditions are contemplated. From these
we hope to deduce what factor or factors regulate the seasonal
abundance of this organism in nature.
So far no attention has been given to the poison
problem in the estuary of the St. Lawrenceo
Noo 24
LARVAL DEVELOPMENT OF SEA SCALLOPS
A. Prakash
In 1961, we continued our studies of the basic
biology of scallops, devoting most of our attention to the
development of their larval stageso These are virtually
unknown but we believe that understanding them will help
explain the population fluctuations observed in regularlyfished
stocks and show why certain offshore banks, e.go,
St. Pierre Bank, furnish such sporadic fishing.
In previous years we tried to study these larvae
by making plankton tows and by setting out scallop spat
collectors, but without success. In 1961, we attempted to
adapt laboratory methods worked out for oysters and quahaugs
by Dr. V. Lo Loosanoff of the UoSo Fish and Wildlife Service.
This involves spawning scallops in the laboratory and rearing
their larvae by feeding them on cultures of minute flagellates.
Our success to date has been moderate but encouraging.
From early spring we held mature scallops in our
aquaria at t~e St. Andrews laboratory and fed them cultured
phytoplankton (mostly Phaeodactylum tricornutum)o All
attempts to ~nduce spaWning by artificial stimulation failed.
However, we made continuous observations on gonad development
of the native population in Passamaquoddy Bay and when
they spawned, we kept close watch on our aquaria. Animals
spawned in our aquaria on three occasions--August 29 and
September 6 and 26. This allowed us to collect fertilized
eggs and rear larvae in filtered sea water in plastic culture
buckets. These were kept at the temperature of Passamaquoddy
Bay, where na~urally occurring larvae~ which appeared to be
scallop larvae,, were developing. The filtered water was
changed regularly and the larvae fed daily~ mostly on
Isochrysis galbana, although some were fed Phaeodactylum
tricornutumo ' Both these phytoplankters were cultured in the
laboratory from starter cultures supplied by the Woods Hole
Oceanographic Institution.
The larvae fed actively on these foods and grew
rapidly for about 2 weeks (see Figure) but thereafter they
grew slowly and many died. Some were kept alive for 42 days
and reached a size of 120 x 135 microns but did not settle.

- 47 - Molluscan shellfish
Laboratory reared~ 8-day-old scallop larvae
(95 x 115 microns) with two types of cultured
food organisms.
We cannot explain why they did not develop to settlement size
(ca. 300 x 320 microns). They received abundant food but it
may have been deficient in some respec·ts. All were dead when
examined on the 48th day. While they were alive , samples were
taken regularly, examined under the microscope, photographed
and preserved for future study . This is the first time that
larvae of this species have been truly cultured.
Larvae of oysters and soft-shell clams mature and
settle in about 3 weeks. It appears that the larval period for
sea scallops is much longer. It may even be longer than the
40 days reported for the Japanese scallop, Pecten yessoensis.
From what we have seen already, it is clear that some
of the early workers made incorrect identifications of larvae
taken in plankton catches. This partly accounts for the
discouraging results of our own plankton studies. At least
we know what to look for now. We plan to continue larval
studies next year.
N. Bourne

Molluscan shellfish - 48 -
No. 25
STATUS OF THE MARITIMES SCALLOP FISHERY
In 1961, scallop landings rose to a record l0a8
million pounds of shucked meats~ valued at 3a2 million dollars-­
an increase over 1960 of 37% in weight and of 52% in valuea All
branches of the fishery--offshore~ Bay of Fundy and Gulf of St.
Lawrence--shared the increase.
Offshore fishery
The mobile offshore fleet supplied 10.1 million pounds
(94% of total catch), valued at 2.95 million dollars, an increase
over 1960 of 35% in weight and of 51% in value. The entire catch
came from Georges Bank. No landing restrictions were imposed on
the fleet this year. A record trip of 62,570 pounds of shucked
meats was landed by the M.V. Barbara Jo after 10 days of fishing
in April 1961. --
The 1961 landings were higher mainly because more
boats were fishing (28 compared with 20 in 1960) but partly
because the boats carried more crew. This brought their
shucking power into better balance with their fishing power.
The unusually abundant year-class that provided most
of the tremendous 1960 catches was greatly depleted in 1961 and
much less evident in our recent samples. To maintain landings
in 1961~ the boats were forced to drag continuously while at
sea (compare Annual Report 1960-61, Summary No. 22) and have
been obliged to redistribute themselves over the bank, fishing
on the northeast peak as well as the northeast edge. They are
now fishing areas they ignored in 1.960 and deck loading is no
longer common, although isolated pockets of the formerly
abundant year-class provided occasional large catches. The
higher wharf price for meats continues to attract fishermen.
Two of the recent additions to the fleet are converted groundfish
draggers.
Two trips were made on draggers to sample commercial
catches, study discards, record cull points and make biological
observations. Further observations were made when two members
of our investigation along with two assistants (Mr. M. Fraser
from groundfish and Mr. E. Sallows from pelagic fisheries)
accompanied the M.V. CaQe Eagle on her chartered cruise
(Summary No. 26). The 50% commercial cull point remains the
same (shell height 95-100 mm}. Discards now comprise 50% of
the catch (20% in 1960). In several areas "cluckers"
comprised 30% of the catchp indicating a high natural mortality
that is still unexplained.
Inshore fishery
The inshore fishery was the brightest since 1957.
Bay of Fundy landings doubled {Digby, N.Sa, 673,000 pounds and
Passamaquoddy Bay) N.B., 49,000 pounds}. Scallops are more

- 49 = Molluscan shellfish
abundant and the increased wharf price has made scallop fishing
more attractive.
Nineteen thousand, four hundred and twenty pounds
(19~420) were landed in 1961 from the southern Gulf of Sto
Lawrence, a 34% increase over 1960o This is encouraging even
though the catches are still far below those of the last gooQ
years, 1956 and 1957. The increased wharf price apparently
provided the incentive to heavier fishingo
Outlook
New boats are still being built for the offshore
fleet, all of them powerful draggers capable of carrying 20
men. By the end of 1962 there will be approximately 40 boats
in the fleet. Sea samples indicate that the year-class now
entering the fishery is not exceptionally strongo We anticipate
total landings as great or greater than those of 1961 but
smaller catches per boat. The increase in fleet size makes
good crews harder to find and this, too, will tend to lower
the catch per boat.
Digby seems to be in one of the cyclic periods of
scallop abundance which are dependent on hydrographic conditions
at spawning times. If abundance remains high and wharf
prices continue at 1961 levels, 1962 landings may exceed those
of 1961.
Scallop landings in the Gulf of Sto Lawrence are
always difficult to predict but the outlook is not discouraging.
When industry learns the results of our survey (Summary No. 27)
scallop fishing may revive and 1962 catches could exceed those
of 1961 because scallops are there to be fishedo Wharf price
will likely determine the outcomeo
Noo 26
GEORGES BANK SCALLOP STUDIES
N. Bourne
In recent years the International Commission for the
Northwest Atlantic Fisheries (ICNAF) has investigated the
possible need for regulating the Georges Bank scallop fishery.
Since 1958, landings have increased rapidly and United States
scientists and industrial officials are of the opinion that
an increase in the ring size of scallop drags would not only
maintain the fishery at a high level but actually increase it.
In 1959, we carried out gear trials (Annual Report 1959-60,
Summary No. 27) comparing catches made by drags with 3-inch
and 4-inch inside diameter rings to determine whether use of
the 4-inch ring would benefit the fisheryo Interpretation of
our results and similar United States data was not clear
because we had to.o little information on fishing mortality
rates, ring size s·election, cull point and the importance of
discards.

Molluscan shellfish - 50 =
At their annual meeting in June 1961, ICNAF
commissioners requested Canadian and United States scientists
to prepare a better founded statement on possible benefits of
larger rings. It was decided that each country should produce
further information and to this end we chartered the commercial
scallop dragger, M.V. Cape Eagte (Captain Roy Langille} out of
Lunenburg, N.S., for one trip August 30 to September 9). Our
cruise was timed to take place between two United States
research cruises. All our studies were made on the northeast
peak and the northeast edge of Georges Bank where the Canadian
fishing effort is concentrated.
We were particularly interested in place-to-place
variations in scallop population density and explored areas
which had received heavy, medium and light fishing. Many
10-minute experimental hauls were made» the distances of bottom
covered were measured with an odometer and the scallops caught
were measured and counted. This provided an estimate of
population density.
Besides this, we compared catches of scallops made
with 4-inch and 3-inch rings as in 1959 but more precisely.
This time an effort was made to study the effect of multiple
linkage,as well as ring size on catches of trash as well as
of scallops.
The results have not been completely analysed but
already show great variations in scallop population densities
in all three areas. This variation can lead to marked sampling
errors, to inaccurate calculations of fishing mortality and to
substantial errors in predicting increases in yield from
introducing larger ring sizes to the fishery.
The difference in performance of 4-inch and 3-inch
rings is not as pronounced as expected. The 4-inch ring
caught fewer small scallops and less trash than the smaller
ring but it did not catch significantly more market-size
scallops. The 50% selection points for the two rings are not
as remarkably different as was expected from what we know
about how mesh size affects otter trawl catches of fish.
Perhaps this is because scallops do not struggle to escape.
Savings effects in scallop drags apparently depend entirely
on the sieving effect of the dredge (mechanical sorting) and
this must often be seriously reduced by the great amounts of
trash (sometimes three quarters of the catch) which plug the
rings. Lighter drags than those used on the Cape Eagle,
towed for shorter periods, might take less trash and afford
a greater savings effect with 4-inch rings than that we
observed.
Analysis of the data is continuing and we hope to
provide ICNAF commissioners with a statement on likely effects
of altering ring sizes.
In the course of this work our station photographer
filmed offshore scallop operations.
N. Bourne

- 51 ~ Molluscan shellfish
No. 27
SOUTHERN GULF OF ST. LAWR~NCE
SCALLOP EXPLORATIO~S
Previous surveys of the southern Gulf (our last
survey was in 1957) have discovered erratically productive
beds of scallops, too small for our offshore fleet but
occasionally stocked well enough for locally-based small
craft. The Department requested a comprehensive 1961 assessment
of these scallop grounds. It was hoped this would
demonstrate opportunities for alternative employment for
groundfish fishermen of this area who are hard hit by recent
waning of cod stocks. It was realizedp however, that chances
for this were dependent on market prices for scallops which
have been low for the last 2 years because Georges Bank
scallops have been so plentifulo The Department's Industrial
Development Service provided funds for the survey.
We assembled current information on likely grounds
through a questionnaire and followed it up by shore interviews
with fishermen and fisheries officerso From this and our own
experience, we plotted a 2-month program of scallop dragging
which was carried out by the Gloucester 27, a medium-sized
(65-ft) Caraquet otter trawler (Abbe Legere, Captain)
chartered for the purpose. Our observer, Mr. Alan Mciver,
supervised and mapped operations and recorded catches of
602 trial hauls in 40 areas. The results are summarized on
the accompanying chart.
In September, when this work was completed, the
Department requested a small-boat survey of grounds available
to Alberton craft and placed a temporarily rigged lobster boat
(Alberton 2B-1013, owner Lemont Hutt) at our disposal for this
purpose. Mr. Mciver and Dr. Medcof supervised the first part
of this work. It was completed by Mro J. So·MacPhail. These
areas had already been covered in Gloucester 27's general
survey and the intensified exploration with the small boat
revealed nothing new. · ·
The flourishing stocks on beds off Boughton Island,
Cape Bear, Toney River, Pictou Island, Richibucto and Bonaventure
were described by radio (Fisherman's Broadcast) and
in writing to interested fishermen who wrote in following the
broadcasto A circular summarizing results is in preparation
and will be distributed to Gulf fishermen this winter.

660 64° 62° 60°
P._Q...
48°~~~ ~ ~A Gulf of
St. Lawrence
47~
N.B.
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Extent or scallop survey'in southern Gulf o{ St. Lawrence, 1961.
Five areas which
showed commercial potential are: ! Richibucto Bed; 2 Boughton Island Bed;
l Cape Bear Bed; !: Pictou Island \fest and Toney River Bed i 2. Bonaventure Bed.

Mobile fleet statistics
GROUNDFISH SUMMARIES
Sampling of groundfish commercial
landings
Comparison of cod from the southwestern
and northwestern sectors of the Gulf
of Sto Lawrence
Returns from 1960 winter cod taggings
Changes in Gulf cod growth
Recent changes in the Gulf of
Sto Lawrence cod population
Factors affecting cod discards aboard
northern New Brunswick draggers
Gulf cod fishery--outlook for 1962
Analysis of returns of 1955-56 Gulf
of Sto Lawrence cod taggings
Participation in the ICNAF mesh
assessment program
Haddock surveys and year-class
prediction for Nova Scotia banks
Halibut studies
Winter distribution of plaice in the
southwestern Gulf of St. Lawrence
Biology of the pollock in the
Bay of Fundy
Catch comparisons between Danish
seiner and dragger
Research vessel groundfish catch
comparisons
Cod swimming speeds
Number
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
53
54 - 55
55 - 57
57 - 61
61 - 64
64 - 66
66 - 68
69 - 70
71
72 - 73
74 - 76
76 - 79
79 - 81
82 - 86
86 - 89
89 - 92
92 - 93

NEw
BRUN.:JWICK
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Noo 28
- 53 = Groundfish
MOBILE FLEET STATISTICS
The St. Andrews Station operates an office at
Halifax for collection, compilation and reporting of mobilefleet
statistics. Log records and interviews of offshore
fishing operations are collected by technicians based at
Sto Andrews, Yarmouth, Lunenburg, Halifax and Sydney, and by
Provincial officers at Souris and Caraquet. These records are
matched with landings purchase-slips colle.c'ted by the Department
of Fisheries, and combined data are recorded on transfer
cards. Two series of keysort holes allow needle sorting by
month of landing and area of captureo Pegbar holes facilitate
summarizing the data for groups of cardso
In 1961 operations were expanded to include scallop
and pelagic fish statistics as well aB groundfish statistics.
Cards were prepared for all vessels over 25 gross tons and
totalled about 10,000. The transfer cards were shipped
quarterly to the Bureau of Statistics in Ottawa for punching,
verifying~ editing, converting and tabulating by IBM methods.
Some tabulations were designed for preparation of statistics
reports to ICNAF, others for research purposeso
In 1962 some of the IBM work will be done at the
Department of Fisheries, Halifax., Eyentually, it may all be
done there, if statistics operations can be adequately
mechanized.
Annual meetings. of agencier3 involved are held at the
end of June to co-ordinate operations and agree on changes to
be made in the following yearo
These Maritime Province statistics are combined with
those of Quebec for submission to ICNAFo Co-ordination is
gradually being achieved. The same IBM cards may be adopted
in the two areas in 1962.
An attempt to combine statistics reports for ICNAF
with those for ICES and FAO proved inefficient, but the experiment
led to improvements in prescribed forms used by each of
the three international agencieso The exercise contributed
significantly to standardization of terms and definitions.
Detailed statistics for Canada and all other countries
fishing the Northwest Atlantic area have been published for
years up to and including 1959 in 'ICNAF Statistical Bulletins.
Summary statistics for 1960 were available in multigraphed form
by June 1961. Detailed statistics for 1961 are due at ICNAF
Headquarters by May 1, 1962o
W. R. Martin

Groundfish - 54 -
Noo 29
1961 sampling
SAMPLING OF GROUNDFISH COMMERCIAL LANDINGS
Each year length and age sampling of groundfish
landings occupies a significant part of the work of several
members of the groundfish staff. A scientist and senior technician
spend part time supervising and co-ordinating the
program. Four field technicians spend up to half time in
collection of samples and four laboratory technicians spend
part time determining ages and summarizing data for use in
various projects. In 1961 a total of 16,223 cod, 12,209
haddock and 3,148 other groundfish species were measured from
commercial landings and otoliths for age determinations were
taken from 2,047 cod, 2,052 haddock and 266 from other species.
Because of recent changes and developments in groundfish
fisheries, a review of sampling requirements and responsibilities
was made during the past year. From this review
specific sampling jobs were re-assigned for 1962. The revised
scheme is co-ordinated through St. Andrews, aided by brief
weekly reports from fieldmen on fleet activities an~ samples
taken. Along with this, stratified age-sampling te~hniques are
being extended for all species and areas sampled. Sampling
effort will continue to be concentrated on southwestern Gulf
of St. Lawrence cod and Nova Scotia banks haddock. Because of
manpower limitations, sampling of other areas and species will
continue to be less concentrated.
Data storage and summarization
New data sheets for field and laboratory observations
on commercial samples have been distributed. These are set up
for easy transfer to IBM cards for data storage. Preliminary
calculations will be carried on by desk calculator at St.Andrews
for the present since IBM equipment capable of accepting programming
for weighting sampling data and for growth studies is
not yet conveniently available in this area. However, storage
on IBM cards will enable groundfish investigators to undertake
projects such as the 1961 ICNAF mesh assessment study with much
less effort in handling data.
Data exchange
Two separate co-operative programs of groundfish data
exchange are currently being carried on. One, initiated through
ICNAF, deals with haddock investigations in ICNAF Division 4X.
In this co-operative study St. Andrews has agreed to supply
sampling data and detailed landings statistics to the U. S. Fish
and Wildlife Service's Bureau of Commercial Fisheries at Woods
Hole, Mass. They, in turn, have agreed to work up these data.
To keep age-d'etermination work consistent with earlier studies
by the St. Andrews laboratory, comparisons of independent
readings by the two laboratories are made. In addition, the
St. Andrews laboratory agreed to send a technician to the Woods

- 55 - Groundfish
Hole laboratory to help for two weeks in reading a backlog of
Division 4X haddock otolithso
A second co-operative sampling program is being
carried out with the St. John°s B~logical Station on redfish
and halibut. Since the St. John°s Station has been taking
responsibility for redfish studies and the St. Andrews Station
for halibut studies in the Northwest Atlantic area, an exchange
of data has been arranged. In this case 9 all commercial and
survey data on redfish taken by the St. Andrews group are sent
to St. John 9 s for their use and in return they are sending
halibut data collections to Sto Andrewso
Noo 30
COMPARISON OF COD FROM THE SOUTHWESTERN AND
NORTHWESTERN SECTORS OF THE GULF OF STo ·LAWRENCE
A. C. Kohler
Because of diminishing cod catches in the southwestern
Gulf of St. Lawrence (ICNAF Division 4T) several Quebec and
New Brunswick draggers extended their fishing operations to the
north shore of the Gulf (Division 4S) in 1960 and 1961. They
fished mostly from Pointe-des-Monte 8ast to Natashquan.
In order to compare the biological characteristics of
cod north and south of the Laurentian Channel and determine the
relationship between these two areas, survey cruises with the
M. V. Harengus were made to both areas in October. The first
cruise covered the regular survey stations (Summary No. 35)
in the southwestern Gulf of St. Lawrenceo The second cruise
was made in the coastal band extending from Seven Islands eastward
about 40 milee. The depths fished ranged from 10 to 100
fathoms. In addition to the survey 9 some 1 9 500 cod were
tagged and released in the vicinity of Seven Islands.
Abundance
The average numbers per tow of cod of all sizes were
comparable in the two areas: 196 in 4S (14 tows) and 192 in 4T
(34 tows). Fish above scrod size, ioe., 51 cm.and larger, were
more abundant in 4S than in 4T: 54 and 18 per tow, respectively.
Size and age compositions
The size and age compositions of the two populations
sampled differed markedly, as shown in the upper part of the
accompanying figure. The length-frequency distribution of 4S
cod was bi-modal with a main peak at about 25 em and a secondary
peak at 58 em. The dominant year-class was that of 1959.
Division 4T cod had a uni-modal size distribution, with a mod$
at 37 em. The dominant year-class was that of 1957.
Growth
The mean sizes at age of cod caught in surveys in the
two areas are shown in the lower part of the .figure. Except

- 57 - Groundfish
for cod of intermediate ages (5 to 7 years)~ cod from 4S are
generally smaller than cod of the same age from 4To The growth
curve of 4S cod reaches its asymptote at about 70 em (age 8)
compared to about 90 em (age 10) in 4To
Maturity
Age determinations of immature and mature cod from
the two areas indicate that cod from the north shore reach
sexual maturity earlier than cod from the southwestern Gulfe
The age at which 50% of the cod are mature is 5 years in the
former and 7 years in the latter areao The state of the gonads,
at least in the males, suggests that cod spawn later in 4S than
in 4To
Fee~tng
Cod from the Seven Islands area appeared to be feeding
less than those from the southwestern Gulfo The percentage of
empty stomachs (for all sizes of fish) was 21 in 4S compared to
11 in 4T o The mean volume of food j_n fish below 70 em in length
was slightly smaller in 4S than in 4T codo Cod 70 em and larger,
however, had much less food in their stomachs than fish of the
same size-group in 4T: 60 cc in 4S compared to 150 co in 4T.
Parasites
No difference in the occurrence of Clavella was found
between the two populations. The frequency of occurrence was
about 50% in both 4S and 4To No Lernaeocera were found in 4S
cod whereas they occurred in 4% of the cod examined from 4T.
No Caligus were found in survey tows in the two areas. The
occurrence of 5 Caligus, however~ was noted from about 1,500
cod tagged in the Seven Islands areao
Conclusions
A co~parison of the biological characteristics listed
above suggests that the cod population sampled in the Seven Islands
area is distinct from that of the southwestern Gulf of St.
Lawrence and that no mixing occurso These observations ,confirm
the results of previous taggings in the southwestern Gulf. The
October 1961 tagging in the Seven Islands area should provide
additional information as to whether or not cod from the northwestern
Gulf are related to those from the northeastern Gulf
and the west coast of Newfoundland, or are a discrete unite
Noo 31
RETURNS FROM 1960 WINTER COD TAGGINGS
Yves Jean
Returns from cod tagging in Sydney Bight in February
1960 and on Western Bank in March 1960 are summarized in the
accompanying figures and tableo These taggings complement
earlier cod taggings during spring to autumn months.

New
Brunswick
-t
... ' '
....
'
-
Feb.-Apr.
- ---. -A._._ ..
t
Aug.-Oct.
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0- Unknown Canada
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Nov.-Dec.
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" - '~ ... ' ........
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Fig. 1. Distribution of returns,from Sydney Bight cod tagging in February 1960, by quarters
(1960 and 1961 combined).
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R:etums from 196o cod taggings ~
Month - No~~ -- faggirig Year ~- No. retumea?y Canada Foreign retums
tagged tagged area returned otter Line Gill Trap Un- Total otter Pair 'l'ot&l Canada and
trawl net lmown truL trawl foreign
total
Feb. 937 Sydney- 196o 33 32 2 1 8 76 34 1 35 111
1900 Bight
u 1961 21 10 0 0 2 33 3 0 3 36
cp
li
0
§
p..
1-1:1
P"
" Total 54 42 2 1 10 109 37 1 38 147
March 506 Western 196o 89 5 0 0 0 94 1 0 1 95
l96o
Bank
It 1961 41 3 0 0 0 44 1 0 1 45
0 "'
" Total 130 8 0 0 0 138 2 0 2 140

- 61 - Groundfish
During winter months most returns from the Sydney
Bight tagging were taken by European trawlers fishing along
the western slope of the Laurentian Channel from Scatari Bank
to the Magdalena. More returns were taken during summer months
by Canadian vessels fishing in the southwestern Gulf of St.
Lawrence, particularly in the Chaleur Bay areao Most of these
Canadian returns came from otter trawls, but large numbers were
also taken by other gears, particularly hook and line. Only two
tags were returned from outside the 4T-4V north area, one across
the Laurentian Channel and one from Banquereau. The results
confirm earlier evidence that the southwestern Gulf of St.
Lawrence cod are fished by Canadians south of the Gaspe coast
from spring to autumn, and that they migrate south to deeper
water off Cape Breton where they are fished by European trawlers
during winter months. Winter ice conditions often restrict the
winter fishing. Such was the case in 1961; hence, the small
number of foreign tag returns that winter.
Most of the returns from the Western Bank tagging came
from the tagging area. A few distant recoveries were reported
from Nova Scotia banks to the east and west, but most recoveries
were taken from Western Bank, Emerald Bank and Middle Ground.
Although tags were returned continuously throughout the year,
more returns were received during winter and spring months when
cod were more concentrated and commercial fishing was more profitable
in 4W. The higher percentage returns from this tagging
than from the Sydney Bight tagging reflect a more intensive
fishery, almost exclusively by Canadian otter trawlers. The
winter fishery is not affected by surface ice problems as in
the case of the Gulf fishery.
No. 32
CHANGES IN GULF COD GROWTH
W. R. Martin
Sampling of commercial landings of cod from the southwestern
Gulf of St. Lawrence for lengths ~d otoliths has resulted
in an accumulation of very useful·· growth data for intermediate
ages in the population. Data for age-groups 6 to 10
and years 1949 to 1960 are plotted in the upper half of the
accompanying figure. Average length-at-age for the period was
at a low in 1950, showed a marked rise from 1953 to a peak in
1956 and a subsequent drop to a lower level in 1959. The rise
seen in 1960 will probably not continue in 1961 data. Although
statistics for weighting 1961 data are not yet fully available,
the basic information indicates a drop back to the 1959 level.
The main interest has been in determining causes for
the increased growth in the 1952-56 period and the subsequent
drop from 1957 to 1959. First efforts were directed towards
verifying the increase in growth and this was accomplished by
checking on the validity of the aging method, by examining
growth records from tagging experiment$ and by measuring increments
on otoliths. At the same time, laboratory experiments
on growth of cod were devised and these showed that both water
temperature and availability of food were important limiting

Groundfish
85
- 62 -
8
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65
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~66~~} c~o
1
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1
52
1
53 • 54 n 55
1
56 1 57 1 58 t 59 '60
Year
The upper half shows average length at age of squthwestern
Gulf of St. Lawrence cod. Data fo·r 1954 were not available. The
lower half shows percentage of cod stomachs containing food, in
which herring were found. These data on food were assembled by
using records made available by Brunel (1951-54), Powles (1955-56)
and Jean (1957~0). The figures in the squares are the number of
stomachs containing food.

- 63 - Groundfish
factorso Water temperature seemed to limit amounts of food
consumed and this, in turn, limited growtho Although experiments
on effect of density or numbers of cod per unit space
were not performed, a literature search indicated that this was
another prime limiting factor in growth of fisho
These three factors 9 population density, water temperature
and food availability 9 were examined in relation to
the southwestern Gulf of Sto Lawrence cod population. Density
data have recently been worked up by Lo Mo Dickie as part of
an ICNAF mesh assessment project in the form of relative landings
per unit effort (ICNAF Annual Meeting 1961 9 Document No. 20,
Fig. 7o5). The data show relatively low density of commercialsized
cod in 1953 and 1954 for Canadian landings by both line
and otter trawl from the southwestern Gulfo Examination of length
distributions of these landings showed also that relative numbers
of large (over 70 em) cod were at a lmv during the 1952-54 period.
Changes in water temperature in the area were investigatedo
Tank experiments (Annual Report 1959-60~ Summary No. 37)
have indicated that fairly large (cao l.r°C) changes in water temperature
are needed to produce noticeable changes in food consumption
and resultant growtho Water temperature series over
these years from the actual depths in which the cod live are not
available. However, surface temperatures from the area are a
general indicator of whether or not significant changes have
occurredo Surface temperatures from Entry Island for 1950-60,
for instance, (Annual Report 1960-61, Summary No. 92) plotted
as quarterly deviations from long-term averages showed no consistent
changes from year to year of the magnitude mentioned above.
Variations in food availability, particularly herring,
have been significant. Sindermann of the U.S. Fish and Wildlife
Service has documented the course of a herring disease,
(Ichthyosporidium hoferi), which reached a peak in the Gulf in
1954 and 1955. Casual observations by Fisheries Research Board
biologists working in the area during these years indicated that
the increased prevalence of dead and dying herring made them
much more available as cod foodo Subsequent assemblage of data
on percentage herring in cod stomachs verified this fact, and
the data are shown in the bottom of the fore-mentioned figure.
An earlier study of food of cod by PoMo Powles showed tha~ fish,
and particularly herring, became more prevalent in their diet
as they reached the larger commercial sizes, and this is borne
out by examination of current datao However 9 the main point of
interest is the rise in incidence of herring in stomachs of the
large sizes of cod to a peak in 1954, coincident with the peak
in herring disease. The length-at-age data follow this pattern
of increase, reaching a peak a year later due to the delay in
cumulative effect of increased availability of food on growth.
The decrease in incidence of herring in stomachs is followed
by a drop in length-at-age, again with a time lag during which
accumulated growth increments were dissipatedo
These studies have led to the belief that the two
main factors involved in this particular rise and fall in
growth of Gulf cod were variation in density of large

Groundfish - 64 -
fish-eating cod and changing availability of one of their
major dietary items, the herringo
No. 33
A. c. Kohler
RECENT CHANGES IN THE GULF OF ST. LAWRENCE COD POPULATION
The size and age compositions of cod in,the southwestern
Gulf of St. Lawrence have shown marked changes since
1957» the year when regular surveys with fine-mesh codends
were started (see Annual Reports for the years 1958-1960).
The average catch of cod per survey tow during the
3rd quarters of 1957 to 1961 (see accompanying figure) shows
a decrease in abundance at both ends of the size range. The
numbers of small fish, 26 em and smaller, have decreased from
49 cod per tow in 1957 to 8 in 196lo Fish 51 em and larger,
corresponding to market and steak cod~ have also declined in
numbers from an average of 63 per tow in 1957 to 18 in 1961.
Cod of intermediate sizes, 27 to 50 cm 9 show a slight increase
from 139 to 166 per tow. The average number of cod of all
sizes has declined from 251 in 1957 to 192 in 1961. As a .
result of these changes, the size composition of cod in the
Gulf, which was multi-modal and spread over a wide range in
1957, has become unimodal and spread over a much narrower
size range.
A study of the age composition (see figure) shows
that young cod of the 1 and 2 age-groups have decreased in
numbers from 55 in 1957 to 13 per tow in 196lo The decline in
the number of large fish affected mostly cod 7 years old and
older. Cod of these age-groups averaged 56 per tow in 1957
and only 7 in 1961. The intermediate age-groups show fluctuations
in numbers, but no remarkable changeso
The age composition of survey catches suggests that
no strong year-classes have entered the fishery since the year
1957. In fact, the decline in numbers of 1 and 2 year olds
may indicate lower recruitment although differences in availability
of small fish at the time of survey may account for
such a decline. The last strong year-class in the Gulf fishery
was that of 1950. This year-class was still noticeable in
catches of 1957 and 1958 but had virtually disappeared in
1961.
The present decline in abundance of large cod in the
southwestern Gulf of St. Lawrence is further confirmed by the
results of winter cruises. It was shown (Annual Report
1960-61, Summary No. 31) that in winter commercial-sized .. cod
had moved into deeper water and were concentrated in relatively
narrow ranges of depths and water temperatures. During two ·
winter cruises in January 1961, a total of 35 tow~ made at
depths of 15 to 200 fathoms from Bird Rock to Scat~ri Bank
caught a total of 17,500 cod. Cod 51 em and larger (market
and steak) made up only 19% of the total catch. The proportion
of steak cod was 4% of the total catch.

- 6.5 -
Groundfish
Jo
19.57
10.5 tows
20
60
10
)0
): 0
0
~
~ 10
Q)
p.
td
0
0
ct-1 0
0
~
Q)
..0
m
10
Q)
bO
0 ro
~
Q)
!< 10
1960
3.5 tows
0 ):
0
~
)0 ~
Q)
p
td
0
0
0
ct-1
0
)0 ~
1Q)
0 tU
ro
~
Q)
)0 !<
10
1961
)4 tows
)0
40 70
Length em
100
2 4 6
8 10 12 14 16
Age years
Size and age .compositions of cod caught with fine-mesh codends
during )rd quarter survey cruises in the southwestern Gulf of St.
Lawrence from 19.57 to 19ol.

Groundfish - 66 -
The decline in abundance of large fish is at~ributed
to an increase in fishing effort~ mostly by otter trawls, in
the Gulf of St. Lawrence in recent yearso It is estimated
that prior to 1947, the year when small otter trawlers began
operating in the Gulf, the total number of cod landed was
about 10 million fish annuallyo These were caught almost
entirely by lines. The total landings by numbers have increased
steadily since, and totalled about 35 million fish in 1960.
About half this amount, 18 million, were landed by European
trawlers fishing off the Cape Breton coast in early spring.
The line fishery, which depends mostly on larger fish, is
obviously the most seriously affected 9 and line catches have
declined since 1958. Unless the fishing pressure by otter
trawlers decreases, the chances of cod escaping capture
beyond age 7 and contributing to the line fishery in the
future are rather small.
Noo 34
FACTORS AFFECTING COD DISCARDS ABOARD
NORTHERN NEW BRUNSWICK DRAGGERS
Yves Jean
Sampling of the catch at sea and of the landings at
the wharf during the period 1956 to 1961 (Annual Reports for
the years 1957 to 1960) provided a measure of cod discards by
northern New Brunswick draggers. A gradual decline in the
portion of the catch discarded at sea has been evident during
these years as shown in the tableo
Percentage cod discards du!ing sampling trips aboard commercial
draggers from 1226 to 1961
Year No. of trips Cod discards in % of catch
B;y: numbers B;y: weight
1956 7 25 9
1957 10 24 6
1958 10 16 7
1959 9 13 6
1960 5 10 4
1961 3* 6 2
*Data based on 3 sampling trips and log records of 4)
, r
commercial trips.
Two important factors have contributed to the
reduction of discards: increase in codend mesh size from
3-inch-manila in 1956 to %-inch synthetic in 1961, and
reduction in sizes selected for landingo The 50~ cull length
for landing has been reduced from over 46 em in 1956 to about
40 em in 1961.

- 67 -
Groundfish
400
A
Small mesh
Large cull
(1,444)
200
'd
0
C)
ct-t
0
0
200
co
h
Q)
,.0
~ 20
0
B
Small mesh
Small cull
(662)
Large mesh
Large cull
(463)
20
Large mesh
Small cull
(126)
40
70
Length em
100
Size composition of cod caught and landed
by northern New Brunswick draggers with various
mesh and cull sizes. The sizes caught by large
mesh and landed with small cull (D) are based on
actual 1961 sampling; others are theoretical.
Numbers discarded are in brackets.

Groundfish - 68 -
In order to measure the relative effect of these two
factors on discards, a theoretical catch curve with a 3-inch
manila codend was derived from 1961 survey catches with finemesh
liner in the codend. This was done by comparing actual
catch with 3-inch mesh codends and survey catches in 1957.
The selection curve obtained was applied to the 1961 survey
catches on the assumption that the distribution of cod within
the selection range did not differ appreciably during these
two years.
To the theoretical 1961 small-mesh catch the large
(1956) and small (1961) culls were applied (A and B in the
accompanying figure) and numbers discarded were calculated.
The numbers represent the theoretical discards in 1961 had
small-mesh codends been used and had the small and large culls
been in effect. Secondly, (C in the figure) the large-cull
(1956) curve was applied to the actual catch with large-mesh
codends in 1961 and discards were calculated. D in the
figure shows the actual sizes landed with the small cull in
effect in 1961. All frequencies were adjusted above 50 em.
The numbers of cod discarded (given in brackets in the figure)
in each case are therefore comparable.
If A, B, C and D represent the numbers discarded with
the various combinations of mesh and cull shown in the figure,
then A-C reduction in discards due to mesh 1,444-463 981;
11
11
A-B " "
" cull = 1,444-662 = 782;
11 11
11 11
A-D = "
both
mesh and cull = 1,444-126 = 1,318.
These are relative numbers based on the numbers of fish sampled
at the wharf.
The relation between mesh and cull effects in reducing
discards may be expressed as the ratio:
2m,_= 13
782 0
These figures suggest that an increase in mesh size has contributed
more toward reducing discards in 1961 than the
selection of smaller sizes for landing, by a ratio of about
1.3 to 1.
It is estimated that the total discards from the
southwestern Gulf of St. Lawrence cod fishery (including Cape
Breton in the spring) have decreased from about 12 million lb
in 1956 to about 1 million lb in 1961. Discard~ by numbers
have been reduced from about 7 million in 1956 to about
1 million in 1961. It is concluded that from 1956 to 1961
large-mesh codends have reduced the numbers of cod discarded
by about 3.5 million in the southwestern Gulf of St. Lawrence.
Further reduction in discards (2.5 million fish) resulted f~om
the smaller cull size for landing.
Yves Jean

Noo J5
- 69 ~ Groundfish
GULF COD FISHE~Y--OUTLOOK FOR 1962
On the basis of surveys with fine-mesh codends conducted
in the fall of the year (October), it is possible to
forecast the main features of the dragger cod fishery in the
southwestern Gulf of St. Lawrence the following year (Annual
Report 1960-61, Summary Noo J7)o
As predicted in 1960, the dominant year-class in
the commercial landings for the Jrd quarter of 1961 was that
of 1956. As expected, the 1956 year-class made up about 40%
of the landings. Cod 8 years old and older made up only 10%
of the landings. The average weight per cod landed, gutted
with head on, was less than 2! lbo It was predicted that the
average landings per hour dragged would be higher in the Jrd
quarter of 1961 than during the corresponding period of 1960,
and would amount to about 550 lb for Gloucester-type draggers.
No data are available at the time of writing, but reports from
our field technicians suggest that the landings per unit effort
in the Jrd quarter of 1961 were higher than in 1960.
The size and age compositions of cod caught during
the October 1961 survey are shown in the accompanying figure.
From these data the expected size and age compositions of the
landings for the Jrd quarter of 1962 were derived. They are
also shown in the figure.
The recent trend towards smaller cod being caught
by draggers fishing in the Gulf is expected to continue in
1962. The bulk of tne landings will be made up of 5-yearold
fish of the 1957 year-classo The modal size landed will
be about 46 em. The average length landed will be around
51 em. This is about a centimetre less than the average
length landed in the Jrd quarter of 196lo Average weight
per fish landed will show a further decline to about 2t lb in
1962o
Survey catches of commercial-size cod in 1961 do not
reveal changes in abundance over that of 1960. It is expected
that the cod catches by otter trawlers in 1962 will remain at
about the same level as those of the Jrd quarter of 1961.
The possibility of hydrographic factors causing
larger concentrations of cod in 1962 than in 1961, at depths
fished by otter trawlers, cannot be excludedo In this case,
it is possible that, despite a decrease in mean size, greater
availability would result in larger catches per unit effort.
Yves Jean

Groundfish
- 70 -
1961 Survey
20
60
10
)0
Q)
td)
~
.p
~
Q)
0
M
Q)
P-1
0
20
40
70
Length em
100 2 4 6 8 10 12 14
1962
Predicted Landings
Age years
0
60
Q)
td)
~
.p
~
Q)
0
M
Q)
P-1
40
70
Length em
100 2 4 6 8 lO 12 14
Age years
Size and age compositions of cod caught during 1961 survey
(October) and predicted.landings for )rd quarter of 1962 in the
southwe_stern Gulf of St. Lawrence.

No. J6
- 71 - Groundfish
ANALYSIS OF RETURNS OF 1955-56 GULF OF ST. LAWRENCE
COD TAGGINGS
Returns from a tagging of Gulf of St. Lawrence cod
during the summers of 1955 and 1956 have been made in each
year since. These provide a series of data from which it is
possible to estimate the rate of total mortality and its
natural and fishing mortality components, for comparisons
with estimates derived from age-composition and catch-andeffort
data.
An initial adjustment of returns by country reporting
was made on the basis of relative returns per weight of fish
landed, compared with Canada as a standard. Using a method
described by Paloheimo (J. Fish. Res. Bd. Canada, 15, 1958),
the adjusted quarterly returns from all tags released in 1955
and 1956 were then used to estimate the magnitude of the
quarterly fishing mortality F, given various postulated rates
of natural and sustained tag mortality (M+M' =X) (Type B
errors, Ricker 1958). Comparison with the calculated fishing·
effort during the same series of quarter-yearly periods suggested
that X was of the order of O.JO and 0.45 for the 1955
and 1956 releases, respectively; a difference which was
reflected in the estimated total mortality rates for the two
releases. Further examination of returns from the different
methods of initial capture and different tags applied within
and between years suggested orders of magnitude for the combined
effects of relative initial tag mortality and nonreporting
(Type A errors, Ricker). Corrections of this order
were combined with best estimation of X and applied to the
data. The resulting estimates ofF were again compared with
the calculated effort and with each other 9 as a basis for
choosing the most appropriate series. The results yielded
values for annual F of the order of 0.40, compared with 0.25
for the uncorrected data. While the revised estimate is
subject to errors which cannot be assessed by this treatment,
there is reason to suppose that it yields values which are
substantially improved over estimates obtained by analysis of
these data heretofore. The values so derived are closer to
our estimates of rates of fishing on this stock, based on
annual changes in apparent year-class strength in commercial
and survey data.
It is expected that these rates may be checked for
recent years by applying similar methods to returns from
tagging in 1959 and 1960 when we have a longer series of
recovery data available from them.
L. M. Dickie

Groundfish - 72 -
Noo J7
PARTICIPATION IN THE ICNAF MESH ASSESSMENT PROGRAM
The Report of the Working Party on Mesh Assessments,
set up by ICNAF in 1959 under the convenership of R. J. H.
Beverton, was presented to the Commission at its 1961 Annual
Meeting. The report, based largely on data for the period
prior to 1959, is to be published as a supplement to the 1961
Annual Proceedings. It contains assessments of the effects
on initial and long-term yield of cod, haddock 9 redfish, and
some other species of the use of mesh sizes between 4 and 6
inches. Results for the main species of Subarea 4 are summarized
in the accompanying table. Immediate losses and
long-term gains for otter-trawl catches of cod are small,
but, as was true in all ICNAF areas, the results generally
indicate gains for all mesh sizes considered. Other gears
might gain substantially with large meshes. At present
fishing levels, haddock yields per recruit appear maximal at
about present mesh sizes. Data for redfish are scanty
relative to amounts available for cod and haddock, but
indicate that for Subarea 4, as in other southern areas,
there would likely be substantial losses for mesh sizes in
the range which yield best haddock and cod catches. Additional
data were presented to show that mesh regulation would likely
increase flounder catches.
The conclusions have formed a basis for the Commission's
recommendation of extension of the 4i-inch mesh
regulation to cod, haddock and flounders in Subareas J and
4, and adoption of mesh regulation for all groundfish species
in the northern part of the Convention Areao
The Working Group was asked to continue its work of
compilation and study of data, with a veiw to including more
recent fishery information for the species considered, to
broaden the species coverage as far as possible, and to
attempt at least preliminary studies of the magnitude of
changes to be expected from increased fishing effort. The
next meeting of the group assigned to work on this problem
will be held in Moscow in May 1962 under convenership of
the writer.
L. M. Dickie

Recent average annual landings in thousands of metric tons (base-line 1957 and 1958) and
predicted percentage change expected with change in mesh size if fishing mortality and
relative size composition of the catch remain as during base-line periodo
Species Mesh
size 4x.a)
(ino) Immedo Long-term
OT Oth. Tot.
ICNAF Division
4vwb)
4RTc)_
Immed. Lpng-term Immed. Long-term
OT Oth. Tot. OT Oth. Tot.
Av. ann. landing 1 12 13
4 + 2 - 1 - 2 - 2
4i 0 0 0 0
Cod 5 - 2 - 1 + 1 + 1
gt - 6 - 4 + 2 + 1
-10 - 8 + 1 0
Av. ann. landing 14 5 19
4 + 2 + 3 - + 3
4i 0 0 0 0
Haddock 5 - 7 - 3 + - 3
5t -21 -10 + -10
6 -36 -16 + -16
Av. anno landing
Redfish
2!-3
4
4t
5
5i
14 18 32 85 69 1.54
+ 1 - .5 - 2 - 3 + 1 - 8 - .5 - 7
0 0 0 0 0 0 0 0
- 2 + 2 + 4 + 3 - 2 + 3 + .5 + 4
- 7 + 2 + 8 + 5 - 8 + 4 +1) + 8
-14 0 +12 + 6 -14 + J +20 + 11
23 3 26 2 - 2
+ 6 - 4 - 7 - 5
0 0 0 0
- 8 + 1 + 6 + 2
-25 - 2 + 9 0
-43 -10 +16 - 6
27 - 27 28 - 28
0 0 0 0 0 0
-39 -29 -29 - 5 - 1 - 1
-61 -51 -51 -15 - 5 - 5
-79 -72 -72 -33 -17 - 17
-95 -55 -41 - 41
a) Western Nova Scotia and Bay of Fundy; area lumped with 4VW for redfish assessment.
b) East and central Nova Scotia banks, except that 1st ~uarter cod fishery for 4V is
excluded.
c) Southwestern Gulf of St. Lawrence plus 1st quarter 4V cod fishery; northern
Gulf (48) included for redfish.
-...]
w
cp
~
o-
g
.p.
t-\
~
m
13'

Groundfish
No. 38
- 74 -
HADDOCK SURVEYS AND YEAR-CLASS PREDICTION
FOR NOVA SCOTIA BANKS
A single survey cruise was carried out on Sable
Island and Emerald Banks in late April and early May 1961.
Regrettably, because the A. T. Cameron was delayed by ice
conditions in St. John's Harbour, the concentrations of haddock
fished commercially in late March and early April had mainly
dispersed. Moderate catches of haddock of commercial size
were taken at the start of the cruise in the deeper water
between Emerald and Western Banks where commercial fishing
had been carried out in depths of 45 to 60 fathoms.
Examination of the hydrographic data suggests that
haddock were co~centrated in water of 3° to 5°C as in 1959
and 1960. In contrast to earlier years, particularly 1960,
water of this temperature apparently covered a much smaller
area in 1961. Concentrations of haddock over a smaller area
of bottom presumably made them more available to the fishery.
Most haddock and cod had spawned by late April and welldeveloped
gadoid eggs were taken in surface plankton tows
eastward to the vicinity of Sable Islando
Year-class history and strength
Surveys begun in the summer of 1958 with theM. V.
Harengus showed that on offshore banks the pre-recruit yearclasses
of 1956 and 1957 were strong, while the 1952 yearclass
was predominant in the commercial portion of the catch.
Winter cruises with the A. T. Cameron during the season of the
main commercial haddock fishery have provided data to follow
the subsequent history of these and other year-classes. Ageand
size-composition data for research-vessel catches from
1959 through 1961, along with the age composition of commercial
landings, are presented in the accompanying figure.
In 1959 peaks in the length composition at 25 em
and 34 em were attributable to the 1957 and 1956 year-classes,
respectively. The 1957 year-class appeared to be about equal
in numbers to that of 1956. Catch per tow for both prerecruit
and commercial sizes was high. Commercial landings
relied mainly on year-classes between 1952 and 1954, with
that of 1952 particularly important.
In 1960 catch per effort for all sizes was reduced
but particularly for haddock of commercial size. The 1956
year-class appeared to be about half as strong as the 1957
year-class (represented at about 32 em). The 1958 year-class
was poorly represented and the 1959 year-class was just
entering the research-vessel catches. Commercial landings
relied mainly on year-classes from 1952 to 1955, with 1952
year-class becoming relatively less important •
..

Quarter I A. T. Cameron Survey
Quarter I Landings
20
1959
40
1959
1959
lO
20
0.....__ ________ ____,_
0
)l
$ 10
J..t
Q)
Pt
J..t
~ o .. - -
§
; JOt
J..t .
Q)
~
20
'59
1960
1961
40
.p
1=1 20
Q)
(.)
J..t
Q)
P-1
{)
40
1960
1961
1960
1961
.....:1
'-"
10
0 I ,....... i i
20
0
20.5 la0.5 6o~5 •6o •58 '56 '54 ·~ ':6 '54 152 ·~
Length Clll Year-class Year-class
~ and size composition of research-vessel haddock catches and age composition or commercial
catches fraa Sable Island-Emerald Bank region, 1959-61. ·
Cj)
~
§
p.
1-1)
.....
CD
::s'

Groundfish - 76 -
By 1961 the 1956 and 1957 year-classes overlapped in
size 9 producing a mode around 40 to 46 cmo Even though the
cruise was carried out subsequent to the major concentrations,
catch per effort was high. The 1956 and 1957 year-classes were
again of about equal strength (similar to 1959)o The 1958
year-class was poorly represented and the 1959 year-class
seemed less abundant than the 1957 year-class at the same
stage. Commercial landings relied mainly on year-classes from
1954 to 1956.
Predictions for Nova Scotia banks haddock
The haddock year-classes of 1956 and 1957 should
continue to provide good stocks and landings in 1962. Poor
year-classes of 1958 and possibly also of 1959 should reduce
populations of haddock on Nova Scotia banks in 1963 and 1964.
Landings in these years should be somewhat reduced from
current levels, although hydrographic conditions may drastically
alter availability as has been shown by contrast between 1960
and 1959 or 1961.
Noo 39
HALIBUT STUDIES
F. D. McCracken
In 1961 most of the effort put into the halibut investigation
was spent in organizing the research program. This
included establishing standard sampling methods for commercial
landings, analysis of research- and commercial-vessel records
for distribution studies, and examination of age-determination
techniques. Present fishing tecnniques were documented by
means of a movie taken during a sea trip on a commercial longliner.
One of the major problems in investigating the
fishery is the difficulty in obtaining reasonably large
samples of fish for biological studies. Compared to cod or
haddock landings, the number of halibut caught and landed by
commercial vessels per trip is very smallo It is, of course,
the high value of the fish that makes the fishery a paying
proposition. Accordingly, with relatively low numbers per
trip being landed, the use of a combination of schemes is
necessary in order to accumulate enough data to establish
biological parameters. The following methods are in use:
a) Shore sampling--information on sizes and ages of fish landed
by the longline ·and otter-trawl fisheries is collected.
b) Research-vessel sampling--all halibut taken on groundfish
research-vessel trips are examined for length, weight,
age, sex, maturity, stomach contents and parasites.
Related environmental observations are recorded.
c) Shore collections of stomachs and gonads--these are preserved
at sea by arrangement with commercial vessel
crews and are shipped to St. Andrews for food
studies and studies· of the seasonal sexual cycle.

- 77 ~ Groundfish
d) Sea trips on commercial vessels-=on these trips fish can
be examined as on research vessels insofar as the
examination does not interfere with the crew 9 s work.
This is a very time-consuming method of data
collection.
e) Data exchange--the Sto JohnQs Station is sending halibut
data to St. Andrews as part of a data exchange
program.
An abundance of information on distribution of
halibut and halibut fishing operations is available in log
records of commercial longlinerso A start has been made at
plotting these data and upon completion of the plot for the
1960 data some points were immediately evidento Canadian
fishermen 9 fishing specifically for halibut~ expend their
efforts mainly on Nova Scotia banks, j_n the northern Gulf of
Sto Lawrence and on the Newfoundland 0anks0 On the Nova
Scotia and Newfoundland banks the main part of the fishery is
concentrated along the edges of the continental shelf around
the 100-fathom line, with occasional trips to shoaler water.
In the Gulf of St. Lawrence the main fishery takes place around
Anticosti Island and in the Esquj.man Charmel between Newfoundland
and the northern shore of the Gulfo In general 9 this
pattern is related to the distribution of the larger members
of the halibut population? while the smaller members are often
caught by otter trawlers operating on the shallower parts of
the bankso
The log records for 1960 also showed a seasonal
pattern in the fishery. From January to March the fishing was
concentrated along the 100-fathom edge of Nova Scotia banks
from Emerald Bank to eastern Banquereau 9 w.ith a few trips
across the Laurentian Channel southwest of Green Banko In
the April-June period, as weather and ice conditions improved,
the fleet spread to the Anticosti area and the shoal water and
southwestern edge of Grand Bankso The summer fishery 9 July­
September, was mainly in the Anticosti and southwestern Grand
Banks areas 9 and this continued until Decembero This pattern
of spreading out as the year progresses seems to be related
to both weather conditions and availability of fish in the
winter? but to the latter factor alone in the summer and
autumno
Preliminary observations on length composition of
halibut landings have shown major differences in size composition
of halibut taken by different fishing unitso The
accompanying figure shows measurements of samples of halibut
from two otter trawlers and one longliner 9 taken in June 1961.
A large proportion of fish landed as incidental species by
the otter trawler fishing on Western Bank was of much smaller
modal size than those taken by the otter trawling fishing on
Sto Pierre Banko Halibut in both otter-trawl catches were
much smaller on the average than those landed by the longliner
fishing specifically for halibut on the Grand Banks.
One of the goals of the present halibut investigations is to
find out what effect such incidental landings of small halibut

23
21
19
17 r
15
bO
s:l
:a 13
a
r-t
fH 11
0
~
9
7 ~ I
5
3
1
I
I
Otter trawl
Western Bank
( 89 fish)
\
"'"-
I
I
I
I
A
. '
55
r-...1
I
I
I
I
I
I
I
I
I
I
I
)
,
I
I
I
I
' I
I
t,
t 1
Otter trawl
:' St. Pierre Bank
1 \ (124 fish)
I \ /
I~~
I \
I I
I \
I
\
.... ... ,
I
I
\
I
I
I
I
I
I
I
, Longline
I
I
I
I
I
I
I
I
I
I
I\ Grand Bank
."-, j \ ( 77 fish)
! \ /~ ! ~~
I \ ~ \ I
,, / I I
,./ \ I
I
I
• A \ I
v \ \ ,·
I \ I
A ' \ /
\ \/ ; \ /' ''. ,
' , ' ../
\ "\ I '
'\ / A v" \ I '
\I
\
I
' \
I I
1\
\
\ .' \
I I '----, ,--\
\1 ' I ·
v . , \
'----../
37 43 49 61 67 73 79 85 91 97 103 109 ll5 121 127 133 139
Length em
Size compositions of halibut from two otter trawlers and one longliner taken
in June 1961.
\
0
li
0
~
~
p..
1-i)
1-'·
CD
P'
-.J
ex:>

- 79 - Groundfish
have on the yield of the stock as a wholec In order to
achieve this goal a better understanding of halibut biology,
particularly distribution, growth~ mortality and recruitment,
must be sought. This is the main object of the
present program.
No. 40
WINTER DISTRIBUTION OF PLAICE IN THE
SOUTHWESTERN GULF OF ST. LAWRENCE
A. c. Kohler
In January 1960 and 1961 the A. T. Cameron made two
cruises in the southwestern Gulf of St. Lawrence. The
locations of five sets of stations from these cruises are
shown in Fig. lA. Line 2 is representative of shallow-water
stations while all other sections pass from shoal to deep
water along the western edge of the Laurentian Channel.
Figure lB shows the numbers and sizes of plaice
which were taken at these localities. For convenience, the
stations were grouped by depth. Shoal-water stations of 28
to 55 fathoms produced small catches of small 9 immature plaice
in both years and at all locationso Similar catches of small
plaice were taken in 1960 at 65 to 100 fathomsc The greatest
numbers of all sizes of plaice were taken from depths of 125
to 200 fathoms in 1960. On the southern sections fished in
1961 most plaice were in the 65- to 100-fathom zone, with
maximum numbers at 100 fathoms.
Comparisons of this winter distribution with those
for other seasons are shown in FigQ 2. The catches at
sections (1) and (2) (Fig. 1) are plotted for June, August
and October 1959, and January 1960, together with the appropriate
isotherms. Catches in June~ August and October were
made by the Harengus and the January catches by the
A. T. Cameron.
Good catches of plaice
section (2) in June and August.
were taken there, and by January
present in shoal water.
were made in the shoal-water
By October very few fish
only a few small fish were
Section (1) indicates a similar pattern with the
greatest numbers of fish in depths less than 60 fathoms
during June to October. In January, however, the plaice were
found in greatest numbers at 150 fathoms.
These data indicate a general pattern of deep-water
concentration in winter, with shallow-water distribution in
spring and summer. The degree and timing of these movements
are believed to vary from year to year.
P. M. Powles

Groundfish
·.
A
60°
#5~
\ ... r.J
·O
',0
Fig. lA. Location of Cameron and Harengus sections referred to in text.
,--------Jan. 1960 1 Jan. 1961
Section #1 #2 #3 #4 #5
5
B
5
~ 35
p..
Q)
0
·r-t
a!
r4
p. 25
CH
0
en
F-4
2 15
~
~
0
0
N
I
\/'\
N
r-i
5
2 0 • 5 6 o • 5 2 0.5 2 o • 5 6 o • 5 2 0 • 5 6 o • 5 2 o • 5 6 o • 5 Length
Fig. 1B. Catches of p1aice made along fi-ve sections during winter and em
arranged by' depth ~ones, all ~atc~s by
. ..
A. T. Cameron.
\ ' '.

A. T. Cameron 16, January 1960
Fig. 2. Numbers of plaice taken at stations along sections #1 and #2
in different seasons.

Groundfish - 82 -
No. 41
BIOLOGY OF THE POLLOCK IN THE BAY OF FUNDY
In 1961 the study of the biology of the pollock
(Pollachius virens L.) was continued, with emphasis on the
distribution in the Bay of Fundy.
Pollock survey
During June 5-10 and August 21-25 the M.V. Roxinda Ann
was chartered for experimental pollock dragging in the Bay of
Fundy in order to sample representative catches from the various
Bay of Fundy fishing grounds (Fig. 1). In addition, the M. V.
Harengus was used for poll.ock and haddock dragging on the same
grounds in July, but very few pollock were caught. Commercial
landings from additional Bay of Fundy areas were also sampled.
Data were obtained on the size, age, weight, sex, maturity and
food of pollock from each ground, but only the sizes have been
analysed in detail for presentation here.
Large fish (65-85 em, 6-11 lb). Large fish were caught on
Wolves Bank during June and August 1961. The same size ranges
were present in commercial landings of handline catches from
this area in June 1960 and from the "River" (between Deer
Island and Campobello Island) in 1915, 1916, 1960 and 1961.
Medium fish 60-7 em 4-8 lb • Medium fish were found
in catches from the "Gravelly'' SE of Grand Manan) in August,
the "Soundings" (S of Grand Manan) in both June and August,
Northeast Bank in Junet and in commercial landings from Yankee
Bank (off Digby, N. S.) and from "Western Hole" (between
Browns Bank and Little LaHave Bank). Fish of this size range
were found previously on Northeast Bank in June 1960, on the
Soundings in July 1960, and in handline catches from inshore
Grand Manan in July 1960.
Small fish (40-65 em, 1-4 lb). Small fish were caught on
Northeast Bank in June and on the "Rip" (southwest of Brier
Island) and the Pollock Shoal (west of Lurcher Shoal) in June
and August 1961. They were also found on the Rip in June 1960.
These observations are in ~eneral agreement with
those of 1960 (Annual Report 1960-61), in that large fish were
caught in the Wolves Bank-River area, medium fish in the
Grand Manan area, on Yankee Bank and the Western Hole, and
small fish off western Nova Scotia (Fig. 1). This suggests
that this pattern is a constant feature of the summer pollock
distribution in the Bay of Fundy 9 even though the tagging
experiments show that individuals mov~ from one area to
another.
Since otter-trawl and handline catches from the same
ground had similar size distributions, and since most catches
were made with otter trawls, it is concluded that gear
selection has had little influence on the observed pattern of
distribution.

'•••
~ .. 4·~
.• !
68
co~'< of
(], -RI"tER ,r•' •••••••••'' ••••
. ~ 1 •X~-WQLYE s = ••
,. ...
'
"':i~ORTH tfRAN~·:t-''N(N
O
,I
.
:'ft.YANK
.. :
·~RAVELLY ../
.. .. . .
SOUNDING ..... c ,-•::
.
·················· : ..· ~··
. . .. ..
. ...... ..·.
.·····,. .. ...
'.......··. . I' .'I
.• .. ,. •'
NQiHl-i. EAST BANK +'-': R I P--;1/l' /4
X
POLLOCK SHOAL-.
LARGE FISH
e MEDIUM FISH
• SMALL FISH
.... .
I, ....... ::
·...: .. •
••••• • • ..
••••
;
.: .. .. -......
-
:.• :
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•
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l
···•·•····
l
•········· ·' .; l ..
.... ', . ..... ,·.
'.· ···•· I .
:
.... ···-"
·:
··......:··.. ...····. :,
:·,..,...... \ ..'
~ ....,
...........
... ( 1 ..· ../
•, ,I •._, :
• ••••••: I : .,
·····... ...
..... •• •••• WESTERN HOLE-e
: ...
~.
•···. .....
..... .................. ,
.·····•.
..
,·.. ...
..
.. ..
··.... .·.··
66
··... .
•..... ....
......
..... .· ..·
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.i
.••
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,
.... .......
.•··.
'•.
.. ·.
I
. ·
.
.
= ·....•
:
•
..,, ..
.. ·,.
,..•.
......
...··.....
.
64
Fig. 1.
Pollock fishing grounds in mouth of Bay of Fundy area.

Groundfish
- 84 -
.···
X TAG AREAS
e JULY- AUG., 1960
.t. SEPT.· OCT., 1960
A
•
I
\
·::/ ( ....... ..
(, "''"i....J········"t.5';:;·/··... t~>
r················\ u
:............. .. ~ ...........····-~;'
•·....
•····· ............ ·····
66
.. ... l
.......
68
X TAG AREAS
e FEB.- APRIL,I961
c
.t. MAY-AUG., 1.961
66
44
,.·
:':'
: l
. ··:"
...... · .. ·
..
·.
.... r'
,..:
~~-f
.... ····= ..... f· ..... ~··'\..~-~~:.~
..··· ······,_
····.
·· ...... .
~..~
····· ...
········....
·.....
·....··
....·
./
.... ···· X- TAG AREAS
e- NOV. 1960
.........-·· ..._ OEC.-JAN., 1960-1
70 68 68
Fig. 2. Distribution of returns from 1960 pollock tagging,
by seasons.
8

- 85 - Groundfish
In addition, the catches with different size compositions
from the same area, e.g. 9 medium and ~mall fish on
Northeast Bank in June, demonstrate that fish of similar size
associate together in schools. This schooling behaviour in
which the fish are segregated according to size will be an
important factor to consider in future analysis of year-class
strength and growth of pollock in the Bay of Fundy.
Tagging
Available information on seasonal variations in
catches and the distribution of spawning fish suggested that
the pollock found in the Bay of Fundy in the summer migrated
south and spawned in the winter in the southern Gulf of Maine.
To study this poss~bility and to learn something of the
pollock movements in the Bay of Fundy 9 1 9 000 medium and large
fish were released in the summer of 1960 with Petersen disk
tags attached by stainless steel wire to the dorsal musculature
between the first and second dorsal fins. An attempt
was first made to tag fish caught with otter trawls, but the
survival rate was low and only 9 of these were released.
The remainder of the fish released were caught on handlines.
Of these, 498 were released in the River (between Deer
Island and Campobello Island) and 493 off northern Grand
Manano
By the time of writing (September 1961), 122 (12%)
returns were made. These are summarized in Figo 2A, B and C
and in the accompanying table. During July and August 1960
returns were confined mainly to the tagging areas, and in
September and October they were concentrated off western Nova
Scotiao In November, December and January returns were made
from the southern Gulf of Maine 9 particularly at the mouth
of Massachusetts Bay, where spawning is known to take place
at that season. The few returns from March and April 1961
were again from off western Nova Scotia 9 and in May, June,
July and August the returns were again confined to the Bay of
Fundy region, with many from the original tagging areas.
Two returns, however, came from the Western Hole (between
Browns and Little LaHave Banks) where a large concentration
of pollock was fished intensively during June and July.
Pollock tagging returns 19609 1961
No. tagged "River" Grand Manan
498 493
No. of returns
Ng.; of returns
Tagging Distant Tagging Distant
area
area
July-Aug. 1960 22 1 0 6
Sept.-Oct.l960 10 2 0 12
Nov. 1960 8 5 1 5
Dec. 1960-Jan.
1961 0 3 0 4
Feb.-Apr. 1961 0 4 0 2
Ma;I-Aug. 1261 16 1 0 12

Groundfish - 86 -
The returns show that at least some of the pollock
found in the Bay of Fundy in the summer migrate south to the
spawning areas of the southern Gulf of Maine in the winter
months and form part of the general Gulf of Maine stock.
No. 42
D. H. Steele
CATCH COMPARISONS BETWEEN DANISH SEINER AND DRAGGER
Since 1960, 14 Danish seiners have joined the fishing
fleet of northern New Brunswick, and it seems likely their
numbers will increase in future years. Although the proportion
of seiners is still small, they have proved efficient,
especially in taking flounders. It was therefore important to
assess their role in this area, and to increase our knowledge
of their effects on the stocks of plaice, cod, winter flounder
and witch.
In October 1961 observers were placed on two typical
commercial vessels operating in the Bay of Chaleur.
Table Io
Characteristics of vessels and gear compared.
Vessel Class Length over all Motor
Roger Dianne Chaleur 59 feet 175 HP Cat. diesel
(dragger)
Aline Marie Cape Island 50 feet 86 HP Ford diesel
(seiner)
Nets Mean mesh size and material Length ~ft}
Cod end Length. Belly Wings Footrope eadrope
ieee
Yankee 35
otter trawl 4 J/8" 4 1/2" 4 1/2" 5 J/8" 52 68
d. c. s.c. cotton cotton
Danish seine 4 1/2" 4 5/8" 4 J/4" 5 J/8" 176 176
s.c. s.c. s.c. s.c.
c - courlene; s - single; d - double
The dragger made tows of two hours' duration while
the seiner averaged one hour and 25 minutes from the setting
of the buoy to the end of hauling. Although appropriate data
were collected throughout the cruise, only tows in exactly the
same area and depth were used for comparison. Other methods
of procedure were carried out as recorded by Yves Jean in the
Annual Repor~of the Biological Station, St. Andrews, N. B.,
1960-61.

40
COD
- 87 -
Groundfiah
30
20
~ 10
.p
F-4
Q)
p.
Cll
F-4
Q)
1 40
Q
Ci1
Q)
li::
I
I
22 37
PLAICE
,'
,.
II
I I
I I
I I
I \
I I
' I
I
I
I \
I \
I \
I \
I \
I \
I \
52
a.
1\
I \
I \ ~
30 f \j\/Da.s.
20
10
I
I
I
I
I
I
I
I
I
I
I
,--~.J
I I OT
I
I
I
I
I \
I \
I
I
I
I
30.5
,,
' " ' --~ ~
v "" '
40.5
Length em
OT
(2 tows 4 3/8" codend)
Da.S. (4 tows 4i" codend)
67 82 97
\
\
\
-,
I
\
\ ,_,
\
'
I \
'
----...:.:'----..... ...
50.5 60.5
Mean numbers and sizes of cod and plaice taken
by trawl and seine during comparative cruise in
Chaleur Bay.

Groundfish - 88 -
Cod and plaice
Comparing mean numbers per tow, it was apparent that
the seiner caught fewer cod but more and larger plaice than the
dragger (see accompanying figure). Equalizing the nets with
respect to mesh and known selection factors only amplified
these results.
A summary of further comparisons is shown in Table II.
Table II. Comparisons between cod and plaice taken per tow by
dragger and seiner.
Species Trawl Seine
Mean length em Plaice 33.8 37.3
Cod 46.6 47.1
Mean numbers per
tow Plaice 140.3 321.5
Cod 280.5 105.9
Numbers above 100~
selection point Plaice 102.3 251.0
Cod 21.0 26.0
Miscellaneous species
Table III. Mean weights (lb) per tow of fish caught in Chaleur
Bay by dragger and seiner.
Species
er tow
Aline M
Cod 1 ) 363 169
Plaice 1 ) 149 420
Winte2)flounder2) 5 0
Witch 8 0
Yellowyail2) 1 0
Skate2 20 1
Eelpout- 2 ) 6 110
Sea Rave~)) 2 0
Lump fish) 8 1
Sculpin2 4 0
1) estimated from length weight
2) estimated from log book
Although fish sizes are available only for cod and
plaice, weights were recorded for other species caught. They
are summarized in Table III. Two significant differences were
apparent. The seiner caught many more eelpout but fewer skate
than the dragger.

Invertebrates
- 89 - Groundfish
Otter-trawl catches of invertebrates far exceeded
the seiner's. In 6 tows the seiner took only 2 sunstars
compared to 14 by the trawler in 4 towso In addition, the
dragger captured substantial numbers of sea cucumbers, starfish,
sea urchins and crabs, scallop and squid. None of these
were taken with the seine.
Wastage
The Danish seiner discarded far fewer cod than the
dragger but kept smaller fish so that no real comparison of
cod wastage could be made.
Plaice.discards were difficult to measure with any
accuracy aboard the Danish seiner. However, calculations
using catch curves and a cull length of 35 em indicated the
seiner discarded 10~ less plaice by weight than the dragger.
Plaice wastage by the dragger was Jl% by weight. Both boats
discarded about 45% by number.
Results indicate that under favorable conditions at
this particular point in time and space, at the end of each
boatvs normal fishing day, the seiner would have caught
approximately as much fish as the dragger, at lower capital
and operating costs. However, the dragger would have twice
as much cod and half the amount of plaice as the seiner.
This dragger would probably have caught more invertebrates.
No. 4J
RESEARCH VESSEL GROUNDFISH CATCH COMPARISONS
P. M. Powles
Comparative fishing with research vessels was
limited in 1961 to a series of seven hauls by the Harengus and
Cameron on Nova Scotia banks in April, and a series of observations
with the Harengus and Mallotus in Passamaquoddy Bay
during late fall. Aims of the cruises were (a) to improve
our knowledge of conversion factors for relating survey catches
by different research vessels, and (b) to make deductions about
behaviour of fish and gear.
Gear and methods
Some of the fishing characteristics of the research
vessels are listed in the following table:

Groundfish - 90 -
Ma.llotus Haren gus A. '.r. Cameron
Length (overall) 55• 84• 175
'.rrawl:
1
Headrope length 38 1 6o• 79'
Rollers Rubber on bosom Rubber on bosan Rubber rollers
Disks on wings Disks on wings
plus chain links plus wing end
roller
Material Cotton Manila Manila
Mesh size 4 7/8 - 3 1/4• 4 5/8 - 4 3/16 11 4 7/8 - 3"
Codend.:
Material Nylon '.rerylene Manila
Mesh size 4 1/2 11 4 1/2" 3"
Auxiliary 1 1/4" li.p.er 1 1/4 11 liner 1 1/4" liner
'.rowing speed,
knots
Fast tows 2 3/4 3.0 3 7/8
Slow tows (ca.) 2 3/8 2 1/4 •••
Duration of tow,
minutes )0 .30 30
Throughout the experiments fish caught were measured
and invertebrates counted. Duration of tow on the Cameron was
JO minutes with the trawl on the bottom. Harengus and Mallotus
tows were JO minutes from hook-up to knock-out, except for
trials over standard distances.
Results
(a) Cameron versus Harengus: In 7 comparative hauls in
fairly dense concentrations of haddock (mostly between J8 and
48 em) the Cameron caught 6,572 haddock, 2.2 times the number
caught by the Harengus. This result compares closely with
the ratio of 2.1:1 observed during the winter of 1960 for
lesser concentrations of haddock. Other species were not
adequately represented in the catch. However, previous comparative
fishing experiments (Annual Report 1960-61, Summary
No. J2) indicated a Cameron-Harengus catch ratio of about 2:1
for cod and about 4:1- for flounders.
(b) Harengus "fast" versus "slow" tows: A series of experiments
varying towing speed on alternate hauls with the
Harengus were carried out in Passamaquoddy Bay. In one part
of the series tows were of the same duration; in the other,
tows covered the same distance. The following table shows the
ratios obtained by dividing the numbers taken in the slow tows
into the numbers taken in the fast tows.

Species
Cod
Haddock
Redfisn
Flounders
Sculpins
- 91 - Groundfish
Harengus
Fast versus slow
Same duration Same distance
( ( 197) 402)
( 325)
(19414)
( 573)
( 205)
( 323)
( 223)
(1,139)
( 745)
Figures in brackets represent total numbers of
fish caught in the fast and slow towso
Fast tows of the same duration as slow tows
(covering a greater distance) caught more fish of all kinds
but relative efficiency was greatest for haddock and greater
for cod and redfish than for flounders and sculpinso Over
the same distance slow tows caught more of all species
(except redfish) and relative efficiencies we+e similar.
Higher net performance ratios with flounders and
sculpins for the Harengus net, in slow versus fast tows, along
with the previously mentioned high Cameron=-Harengus ratios for
flounders indicate escapement of these species from the
Harengus net during the faster tows. Probably escapement
occurs under the footrope or ground warps and further experimentation
in weighting the footrope of the Harengus net is
suggested. Higher net performance ratios for cod and haddock
in slow versus fast tows (same distance) were unexpected
beoause of the faster swimming capabilities of these species.
(c) Mallotus "fast" versus "slow" tows: Aft$r various alterations
to hauling gear and net, the research vessel Mallotus,
which has not usually been used for otter tra~ling, fished
for several days, alternating fast and slow h•uls. The
resulting observations are summarized in the following table:
Species
Cod
Redfish
Flounders
Sculpins
Mallotus
Fast versus slow
Same guration Same distance
~· ~4 ~
(245)
( 271)
( 54)
( 80)
(290)
(457)
Figures in brackets represent total numbers of
fish caught in the fast and slow tows.
The net performance ratios were generally higher for
slow tows, both for same duration and same distance. These
results indicate the need of matching net size and towing
speed, since fast tows apparently were "distorting" the net
or possibly lifting it off bottom.

Groundfish - 92 -
The relatively high catch ratios for the more
pelagic redfish in fast tows of both the Harengus and Mallotus
(same distance) suggest that in both nets the headline was
raised further off bottom.
These kinds of experiments need to be continued
where fish are present in greater numbers and where strong
swimmers 9 such as pollock, and less demersal forms, such as
redfish or silver hake 9 are better represented.
No. 44
COD SWIMMING SPEEDS'
F. D. McCracken
During the fall and early winter a series of tests
were carried out aimed at determining maximum attained swimming
speeds for different sizes of cod, at both cold- and warmwater
temperatureso
Cod for testing were taken from holding tanks in
the laboratory where they had been kept and fed for varying
periods of timeo Swimming speed was tested in a cage 6 ft
long by 2ft wide and deep, covered with netting. This cage
was slung alongside the research vessel Mallotus and towed
with the long axis parallel to the course of the vessel.
Speed of current was measured by means of a Gurley current
meter suspended about mid cage.
Single cod were placed in the cage and after a short
time interval (about 10 minutes) the cage was towed at a
gradually increasing speed until the cod could no longer maintain
its position in the cage and was swept against the back
wall. All cod, even those blinded by "popeye", oriented into
the simulated current created by towing the cage.
In early tests speeds were increased at JO-second
intervals and the maximum speed recorded was the average
speed for the last JO seconds in which cod could maintain
their position in the cage. In later tests this time interval
was reduced to 15 seconds.
The maximum speeds in a series of tests carried out
at temperatures of about 10°0 and 1°0 are averaged and presented
in the accompanying table for various sizes of cod.
Although there is considerable variation in the
results, it is clear that average swimming speeds increase
with size of fish. Maximum speeds recorded were aro~nd ·. 5i
to 6 ft per sec (Ji to Ji knots) for cod of 70-79 em.

- 93 - Groundfish
Length range 10°0 1°0
em A* B* C*
ftLsec ftLsec ftLsec
20-29 5.2(1)
30-39 4.3~2) 4.3~11~
40-49 4.5 5) 5.1(3) 4. 2 10
50-59 4.5(2) 5.2( 7)
60-69 4.8(3~ 4.8~2) 3.9( 1)
70-79 5.4(3 6.1 5)
80-89
90-99 5.9(1)
*A = 30-eecond speed increase interval;
*B and *C = 15-second speed increase interval;
Number of fish tested shown in brackets.
The results show that slightly higher swimming speeds were
attained when towing speeds were increased at 15-second
intervals. Speeds attained with high- and low-temperature
cop~itions were not markedly different.
T. Miyata
F. D. McCracken

HERRING (PELAGIC) SUMMARIES
Pelagic fish landings
The Bay of Fundy herring fishery
The age and growth of Charlotte
County "sa~dines"
Studies on the origin and recruitment
of Charlotte County sardines
The feeding and growth of young herring
in captivity
Herring tagging 1961
Herring spawning survey
Herring larval studies
Herring fisheries of the western
Gulf of St. Lawrence
Gulf of St. Lawrence herring
populations
Explorations for pelagic fish 1961
Swordfish investigations 1961
Number
45'
46
47
48
1t9
5'0
5'1
5'2
5'3
5'4
5'5'
5'6
hu.
95'-97
97-100
101-103
105'-107
107-108
108-110
110-112
113-116
116-119
119-121
121-125'

'.
.....
....
Gulf
···of
St.LJwrence
·r:I~.Jnn
en Is.
Breton Is: ..
(" .. : .
. .
) h•r She.~ Is
Lure ••• 11
• • • • • • ruskt- .
.t\.....
so ble
1 ° "
"·,.~.·
s··
....
·'----~~::.:
~-·
,.r'"" 3onq•Jcff'.Ou
'1.... ..... ~
0 ° 0
0 '•
Gulf
or·
.... .---· ... )
0
:"s' ";;-;:m s .Bk. , ..... .
"'\ r . _) ...
·· ..... 1 .. r .····
)
.·
...
• •
· ...

No. lt5
- 95 - Herring (Pelagic)
PELAGIC FISH LANDINGS
Landings ot all pelagic fish species in the Maritimes,
Quebec and Newfoundland in 1961 amounted to 228 million lb--30
million lb less than the 1960 landings and 70 million lb less
than the long-term (1939-59) average landings. Only in 1256
(222 million lb) were landings lower than they were in 1961.
The landed value of the catch in 1961 was 15,118,000--18% less
than the value for 196o ($~,265,000) but 9% greater than the
long-term average value ($4,697,000).
The reduction in the 1961 landings as compared with
the long-term average was due to (a) a decline in herring
landings from 26lt to 210 million lb, (b) a decline in mackerel
landings from 30 to 15 million lb, and (c) a decline in tuna
landings from 0.6 to O.llt million lb. The 1961 Swordfish landings
were the same as the long-term average landings (3.2
million lb).
The accompanying figure compares the long-term
average landings ot herring, mackerel, swordfish and tuna with
landings in 1960 and 1961 for tour areas or the Canadian
Atlantic. The most notable features ot this graph include the
recent reductions in herring landings in the western Gult ot
st. Lawrence and in Newfoundland, and the generally low landings
ot mackerel and tuna in all areas. Herring landings in the Bay
or Fundy area (including Yarmouth Count~ have been considerablr
better than average tor the last two years although 1n 1961
they were about 30 million lb (nearly 2~) less than the alltime
record landing of 160 million lb in 1960.
Mackerel landings, although 5~ below the long-term
average for all areas, were relativelf good in Newfoundland
where it was reported that the catch jumped trom almost nothing
in 1960 to 2.2 million lb in 1961. However, in the western
Gulf and the outer coast ot Nova Scotia the landings were
below (65~ in the western Gult and 55~ in Nova Scotia) the
long-term average. In the Bay ot FUndy where onlf 3~ ot the
total mackere1 landings are made the catch was 1.~ million lb
or 8~ greater than the long-term average.
. Compared with the peak swordfish landings ot almost
7 million lb in 1959 the 1961 landings ot 3.2 million were
down about ;~.
- The 1961 tuna catch ot about 0.14 million lb, although
7~ less than the long-term average was nevertheless
double the 196o catch. The increase took place ch1etly in
the usual tuna fishing areas in Yarmouth, Lunenburg and Halifax
Counties. However, some tuna (lt,ooo lb) were taken ott Cape

Herring (Pelagic) - 96 -
Herring
150
~ 1939-59
~ ' ' 0 CJ 1960
100 ''. IliEl . 1961
50
....
....
..... , .. ···"'
.. :.
.
.. ·.
en
~
..
0.
....
.. ..
0 ~
~
P.
Mackerel
tt-.4 12
0
en
s:::l
0 6
r-1 ""
r-1
.....
::s:
3·0
1.5
Swordfish
o.6
Tuna
Q)
tt-.4 .o a1
-1-f.)C: ~ ..-t >a •
;_:; (J] Q) Q)QSof.) rc
-., e.. of-):>0
r-1
•IH ~ goo >a tl1CH ~ CH
.== o·as lZiOl J:Q Q, :z;
H

- 97 - Herring (Pelagic)
Breton and an all-time record (as far as spGrts fishing vas
concerned) was established in Conception Bay, Newfoundland,
where 133 fish were caught.
S. N. Tibbe
tt. A. McKenzie
THE BAY Of PUJIDY HERRING FISHERY
The herring ti'h~ry in the Bay of Fundy (Fig. 1) is
principally tor "sardines" but some large herring are taken
ott Grand Manan and on the Nova Scotia side of the Bay. The
catch, which reached an all-time high •f 16o million lb in
1960 1 declined in 1961 to 130 million lb but this was still
30 m1llion lb higner than the long-term (1939-~9) average.
The drep 1n landings occurred entirely in Charlotte County
where the catch (28 million lb) was the second lowest in 20
120r,------------------------------------------------------~
IC
N.B.•
N. S. = x· · · · ·x ·
(.')
C;
2
-j
0
L..
u..
0
~ J
'-
'""""
0
..J
....J
~
80
60
4C
20
.,.......... ,.>\
.... .... '•")('' . )(
it'. ..""'... ····~. :
..
... .
. ·~
..J••••'{:
)(• ~··,r
.. x·
?'... ~ •·
.· ··x··· ·. . .. :x
.)(' ..
•
\
•
·"
)(
..
.
' ~
~ ... ~
40
Figure 1.
45
Bay of Fundy herring landings (Yarmouth to Charlotte
County inclusive). Figures tor 1960 and 1961 are
preliminary.

Herring (Pelagic) ·~ 98 ,.,
yearsn In Saint John County the catGh increased from 5 million
lb in 1960 to 13 million lb in 196ln On the Nova Scotia side ot
the Bay of Fundy landings in 1961 increased to an all-time peak
of almost 90 million lb--90% of which was taken in Digby County.
The high landings in Saint John and Digby Counties (located
almost across the Bay of Fundy from ~ach othe:d did not extend
farther up the Bay although Yarmouth Cow..ty immediately outside
Digby County did have landings 61% higher than the longterm
average and slightly better t~~ in 196oo
Detailed records of the different types of herring
~ear licensed on the New Brunswick side of the Bay of Fundy
(Charlotte and Saint John Counties) have been obtained annually
since 1957 from the Federal Department of Fisheries (St.
Andrews Off~.ce).. Daily ca.teh rc--jcords by g·ear during the same
period have been obtained through ti:1e kind cooperation of
Connors Bros. Ltd.~ Black 8 s Harbou.:r,·~ N.. Bo 'J H .. w .. Welch Ltd.,
Fairhaven, N .. B .. ll and the Un:!.ted Sta·:•:.es Bur·~au of Commercial
Fisheries la.-::;.oratory at Boothbay Harbor:~ Malne.. From these
records it has been possible to dete::·m:ine t.h!!! relative success
of the diffG:t.'"ent bz-anches of the f:i.sh&:r.·J on the north side of
the Bay of ~L~dy during this periodo
Table I shows (a) the number of units of gear licensed
and the number of weirs built and oper&tedJ (b) the total catch
by types of gear, and (c) the average eaten by type of gear.
In 1961 the number of weirs licensed was about 10%
below the ave~age for the previous four years but only about
half the average number of drag seir..es were licensed. On the
other han.d there was no change in the number of purse seines
licensedo
Weir landings, both total ru1d average, were the
lowest durlng the five years that records have been available.
The total drag-seine catch was also the lowest during the
period but the average was only second lowest. Purse-seine
landings were also down, both total and average, breaking for
the first time the increasing trend shown over the last five
years ..
Beginning in 1957 records of herring landings by
gear on the New Brunswick side of the Bay of Fundy improved
year by yearo Records were also obtained for som~ of the
herring caught off Digby County but landed in New Brunswick
and Maine. These records too gradually improved and in 1961
details of the location and ownership of the weirs in Annapolis
and Digby Counties (Fig.. 2) were obtained as well as records ot
some of the individual weir catches. Through the efforts_ot
Mr. E. Go Sollows, 16 purse seiners(a total of 17 were licensed
in New BI~.swick and 3 in Nova Scotia) operating in this area
agreed to keep log books. Twelve of these boats operated almost
continuously from July to late autumn off the Digby-Yarmouth
shore while the other 4 did so on a more or less casual basis.

- 99 - Herring (Pelagic)
Table I. Details of herring gear and catches in Charlotte and
Saint John Counties 1957-196lo
(a)
Ge~ 'S21 g! un;itil
li~i~i Licensed Licensed
Year Licensed Built Not built drag seines purse seines
1957 371 290 81 22 17
1958 376 269 107 31 13
1959 3B6 271 115 25 19
1900 lr03 270
21 15
1961 345' 261 1~~
14 17
(b)
Iot.a,l_«;,atch {millions of Po2Y!l.llU
Year Wei:rs Drag seines Purse seines Total
-...-.-..-
1957 73.4 4.2 8.2 85.8
1958 25 .. 5 2.5 7o9 35·~
195'9 74.7 6.6 19.1 100.
1960 76.~ 5.9 37·0 119.2
1961 17. 1.6. 27.2 46.6
(c) mra,ge ~a t~nLYn;i t ~! g~a.: ' 12Q'!J.llSl s l
Year Weirs 1 Drag seines 2 Purse seines 2
1957 25~,237 193,1M. 481,8o4
1958 9 ,728 81,3 606,413
1959 275,6~7 26Lf.,l8Lf. 1,003,507
1960 282,6 8 279?037 2,Lt-67,545
1961 68,329 114,231 1,602,600
1 Operated
2 Licensed
Partial records from 6 purse seiners show that from
early July to late rallthey averaged about 45 days fishing,
making on the av·erage 105 sets with an average catch of about
28 thousand lb per set. About 60% of the fish were marketed
in Canada and the remainder in the State of Maine.
Over 55 million of the 90 million lb or herring
caught in 1961 on the Nova Scotia side of the Bay of Fundy
were landed on the north side of this Bay--about 30 million lb
in Maine. These exported fish were caught principally in
weirs and purse seines, about 60% in the latter. The Nova
Scotia landings from this fishery on the south side of the Bay

Herring (Pelagic) = 100 -
•
Figure 2.
Weirs in Annapolis and Digbf Counties
I
x - Licensed only 196~
•- Licensed and built 1961
Weirs licensed in Annapolis and Digby Counties
1961.
or Fundy amounted to about 35 million lbo Records for these
landings (June and July available only) show that in addition
to weirs and purse seines herring were also caught in gill
nets--about 1/3 in each of these types of gear during these
monthso In August and September a much higher proportion must
be taken by gill nets as the autumn spawning herring concentrations
in the Tr1n1ty-Lurcher are~ are exploited only by
this type of gear.
In 5Ummary it is noted that herring weir catches in
1961 on the New Brunswick side of the Bay of Fundy declined
progressively westward from Saint Johna This trend continued
into the State of Maine where weir catches in 1961 amounted
to only 10% of the 1960 catches.
Drift-bottle experiments (Appendix No. 83) indicate
that the surface circulation in the Bay of Fundy in 1961 was
distinctly of the open type,.ma..QY returns from Bay of Fundy
releases coming from the coast of Maine while those from the
New Brunswick shore west of Saint John were less than usual.
This change in the Bay of Fundy circulation may have played
an important part in the poor fishery on the New Brunswick
and Maine side of the Bayo
Ra A., McKenzie
C. Do Burnett

No. 47
- 101 c> Herring (Pelagic) .
THE AGE AND GROWTH OF CHARLOTTE COUNTY "SARDINES"
Three thousand two hundred and fifty (3,250) fish
were sampled from April to Deaember 1961 inclusive, from weir
and purse~seine landings at Connors Bros. Ltd. at Black's
Harbour, N. B. The samples were examined for total weight,
individual total and standard lengths, and vertebral numbers.
Otoliths were extracted for determination of age, growth
season, 1st-year growth, hatching season and other population
characteristics. Hitherto length frequency was the only
technique used to determine age, growth and hatching season
par·ameters for western Atlantic "sardine" herring. Scales
have been examined unsuccessfully~ but no previous attempts
have been made to use otoliths.
The relationship between standard and total length
was determined for future comparative :and racial studies, by
plotting monthly mean total and standard lengths.
A regression line of slope 1.154 produced a relationship
as follows:
and a con·version factor of:
Y = o.465 + 1.154X
y = 1.191X
where Y = Total length
X = Standard length
Figure 1 shows length and age frequencies by
quarters for 1961; age is given as the number of completed
years as indicated by hyaline winter rings on the otoliths,
e.g., a 2+ fish has completed 2 years~ and is in its 3rd
year.
Figure 1 shows that length frequencies are bimodal,
due to two dominant length (and year) classes. From
April to December the fishery is supported by mainly 1+
£ish (1960 year-class) and to a lesser extent by 2+ fish
the proportion of whic~ decreases throughout the year. T~e
~udden presence of 0+ fish in the last quarter suggests an
autumn recruitment at that age.
The seasonal growth pattern has been determined
by recording the proportion of otoliths with opaque or
actively growing edges ("open") in each monthly sample, and
by following changes in specific growth rate and relat~ve
condition. All three parameters show that active growth
commences in May and falls off around September, being at
its highest in July and August.

olo
40
2.0 -
0
/ -.
.
/\
I .
. '_,.
. ...........
/ . '·
Apnl- June
( 12 00)
80
40
0
r-
~
r-
(1200)
~
1"1
1"1
.....
I:S
aq
..
-"tt
(I)
t'
-i-1-
D
40 -
July- Sept.
( 800)
eo
t-
~
( 800)
20 -
0
_/.
•
. "· / '·-·
I - '\., ,.--·,_
·--·--· --...._,_
40
0
1-
.....--
r---1
-
......
0
1\)
40 1-
20 1-
0
./·\ /·'-.
/. ., ·,.
/ / "
........ I - ·--·-· I .........
Oct.- Dec.
(I 300J
10 15 20 25
Total Len9tll (em)
I
I
30
80
40
0
--
r--
,.-,
0-1-2-~
A.9e
(1300)
Quarterly length and age frequencies for Charlotte County sardines 1961.
I
4-5

~ 103 = Herring (Pelagic)
Table I. Mean length and weight for age and year-class.
Total number af.f1sh2.,.369.
Yearclass
Age
H~~ l~.g.g:tba
Spring Autumn
~an X§1 gtl:t
Spring Autumn
yr
em
em
gm
gm
1961
1960
1959
0
1
2
11.11
13.29 18.615
16.70 21.22
9.12
17.38 56.23
38 ... 02 87.10
Mean lengths and weights for yearc~class and age were
determined by combining lengths and Wt3ights. for all fish with
"closed" otoliths (a hyaline or winter edge). At that time,
(i.e.~ spring and autumn) little or nQ growth was taking place.
The data are shown in Table I.
Sampling will be contirrued to follow year-to-year
variations in annual and seasonal growth~ and catch composition.
No. 48
STUDIES ON THE ORIGIN AND RECRUITMENT
OF CHARLOTTE COUN:rY 19 SARDINESf11
T. R. Graham
The Charlotte County "sardine" fishery is one of the
most valuable herring fisheries of the northwest Atlantic, and
information on the origin and recrui.tment of the sardine stocks
is essential and basic to any development of population
dynamics or yield predictions.
Origin. As far as is known there are no large stocks
of mature adult herring or extensive spawning grounds in the
waters off Charlotte County. Extensive spawnings take place
off southwest Nova Scotia and on the northern edge of Georges
Bank. Minor spawnings are reported to occur at Grand Manan,
several inshore areas in the Gulf of Maine and off King's
County, N. s. in the Bay of Fundy. Results of larval, hydrographic,
serological and parasitological studies suggest that
Charlotte County sardines are recruited chiefly from southwest
Nova Scotia spawnings. It was felt that further support for
this conclusion could be obtained from studies of otolith
characteristics and such studies were carried out in 1961.
The samples of sardines used were collected primarily
for age and growth analyses (Appendix No .. 47). Adult

Herring (Pelagic) - 104 -
herring were sampled from commercial gill~net and purse-seine
catches off southwest Nova Scotia in August and September and
from experimental otter-trawl catches on Georges Bank in
Octobar (Ao To Cameron cruises # 46 and 47)o The adult fish
were examined for total length, sex and maturity. Otoliths
were removed from all fish for determination of age, hatching
season and 1st-year growthu
The age and length data for Georges Bank and southllest
No·va Scotia adults show that the two stocks are similar
in age and growth parameterso The same number or age classes
(7) were represented and the same year-class (1958) was dominant.
Mean length differed by 2o7 em and mean age by 0.42 years.
Sex and maturity data showed that 95% or the Nova Scotia fish
were mature compared to 20% of the Georges Bank fisho This is
probably not significant, however~ because or the time
difference in samplingo On the basis of the above datai
therefore~ these two stocks of fish are indistinguishab e.
Hatching season was determined for all fish by
examining the otolith nuclei under a binocular microscope.
Three 'types of nuclei were differentiated, indicating autumn
(A)~ winter (I) and spring (S) hatchingo The 1st-growth zones
or the otoliths (01Vs) were measured with a micrometer eyepiec:e))
and ranges and means calculated for each otolith type.
Otolith lst·=·growth zone measurement (0 1
) of sardines and
adult.so Number of fish in brackets.
Char.Coo sardines Nova Scotia adults Georges Bk. adults
Nuclei '33220l '300l '120l
type % Mean Range ~ Mean Range ~ Mean Range
Hyaline 53 22 15-29 48 23 14-30 58 25 18-31
(A)
Inter•,g
mediate 23 20o5 13-27 23 21 13-28 17 25.5 18-31
(I)
of~yue
24 20 11-25 29 21 14-29 25 23 15-29
~
The above table shows the proportions of spawning types
and o 1 measurements of otoliths for the three areas. On the
basis of these parameters the Charlotte County sardines have a
greater affinity with Nova Scotia adults than either have with
Georges Bank adults.
Eecruitmcnt. Age and growth studies or the sardines
showed that in th& ~ and 3rd quarter or the year the dominant
age was 1+~ and that in the last ~arter there was a sudden
influx of 0+ fish (Appendix No. 47). The accompanying figure

=> 105 = Herring (Pelagic)
~hoys the mon·chly proportions of the tbl-ee otolith or hatching
types in 0=2 year fish. Peak abundance of spring-hatched fish
in May and of autumn-hatched fish in November suggests that
recruitment to the fishery takes place almost exactly a year
atter hatehingo It is also ·apparent that autumn-hatched fish
are the main source of supply to the fisheryo
%
80
. (3,250)
~ Autumn hatched
20
--·-;.-.-- ..... ........
..
0 L---~----~-----L----L----~--~
Apr. May J·ur....o Jul. Aug. Sepo Oc·to Nov. Dec.
Nu·Jleus type frequency (0-2 year fish)o
Winter hatched
Spring hatched
The above studies have added to our knowledge of the
origin .and recruitment o$ 11 savdine" ·~.Q,er~i;Q.g, b~~. it is obvious
that additional information is needed and studies of seasonal
variation in age 7 growth and recruitment of the sar~ines should
be contirruedo In addition~ comparative morphometric and
meristic studies of sardines and adult spawners should be
initiated.
No. 49
To Ro Graham
THE FEEDING AND GROWTH OF YOUNG HERRING IN CAPTIVITY
During the summer of 1961 an experiment was carried
out at the St. Andrews station to study methods of handling
herring in aquaria and to find a diet that would produce
growth.
Live herring from 10 to 18 em total length were
obtained from weirs in Passamaquoddy Bay and transported to
laboratory tanks without removing them from water at any time.
The tanks were made of fibreglass, were supplied with water
pumped directly from the sea and were equipped with airstones.
Three sizes of tanks were tested but only in the

Herring (Pelagic) - 106 -
largest size (6 ft diameter X 4 rt, ca 650 gallons) did herring
survive, reed and grow throughout the summer months.
About 600 to 700 fish were placed in each or two
650-gallon tanks. The mortality rate was high during the
first few days but this gradually decreased as the fish became
accustomed to the new environment. Feeding commenced on the
12th to 14th day and continued throughout the length of the
experiment (89 days). The tanks were cleaned at irregular
intervals by siphoning out the unused food and other deb~is.
Four different diets were tested: (a) a mixture of
sea mussels and canned pet food (equal parts) with small
quantities of terramycin and yeast extract, (b) a mixture of
poultry feed and herring in equal proportions, (c) chopped
squid and (d) small pieces or herring. The captive herring
ate all four foods, but appeared to have difficulty in getting
adequate quantities of the first two types. These were finely
ground mixtures that disintegrated rapidly and sank to the bottom
of the tankso Chopped squid was more buoyant and the par~
ticles were fairly large but supplies were inadequate thus
20
18
Mean
12
10 50 70 90
D~s

a> 107 - Herring (Pelagic)
preventing testing for a long period. Efforts were concentrated,
therefore, on feeding with dead herringo The captive
herring seemed to prefer this type or food which was stored
for about 10 days at 0°C for partial softening of the flesh
before being presented in small pieces two or three times
daily.
The growth rate of the captive herring was obse~ed
from June to September in one of the 65'C>=gallon tanks which
(after the high initial mortality) contained 500 to 600 fish.
Four samples of fish were taken during the periodo Length
measurements were made to the nearest milli.metreo Water
temperatures inside the tank ranged from 9o0 to 14.3°C. The
fish were fed twice daily with about 500 gm of the herring
flesh diet.
The accompanying figure shows that during the first
42 days of the experiment, the increase in mean body length
was small (0.4 em). This ean be attributed to the fact that
the fish passed through a period of starvation during that
time. During the whole 89-day period, however~ mean length
and range increased progressively~ the mean length by 3.0 em.
The growth rate was somewhat slower from the 60th to the 89th
day' than it w·as between the 40th and 60th days. TlUs was
probably the result of an obse~ed decrease in food intake
during early September when there was a significant rise in
water temperature.
Results of this preliminary study show that herring
can be kept alive and even show a steady increase in body
length in an artificial environment.
No. 50
HERRING TAGGING 1961
S. N. Tibbo
Naresh Das
Herring tagging experiments were carried out in
1961 in four different locations with 2,740 tagged fish
being released. Two types of tags were used, both attached
through the back just ahead of the dorsal fin; 1 1 752 were
disc tags of scarlet-coloured plastic attached by nylonelastic
threads and 988 were plastic spaghetti tags, 500
scarlet and 488 yellow. Most of the spaghetti tags were put
on at the Magdalens, the remainder at Hospital Island in
. Passamaquoddy Bay. .
The only comparison of tags possible so far is at
Hospital Island where 288 spaghetti tagslyielded 22.6% returns
and.200 dis-c tags gave 12.5'J returns~ ont.y about half as
good. A breakdown or the spaghetti tags according to colour
shows.that the scarlet tags yielded 33% returns and the
yellow tags 1.7%. These results are in line with earlier

Herring (Pelagic) - 108 -
tests of these colours with cheek tags. The sample lot of
spaghetti tags were exhausted in the Hospital Island and
Magdalen taggings.
Area
Tagged
Recaptures
Passamaquoddy Bay
Magdalen Islands
St. Mary Bay
Yarmouth Bar
no
488
1,4oo
474
378
no ~
90 18.lf.
0 o.o
17 3.6
5 1.3
The recaptures from the different tags used at
Hospital Island show the same pattern, all but 1 being taken
within this Bay.
The Magdalen Islands tagging was done at the very
end of the spring herring season--the traps all being ashore
as the tagging ended. There have been no recaptures recorded
from this tagging so far, possibly because there is little or
no herring fishing at the Magdalens except in the spring. It
may also mean that there has been no movement to any other
fishing region.
The recaptures from the Yarmouth Bar tagging were
all at the head of St. Mary Bay as were those from the st.
Mary Bay (Sandy Cove) tagging. A movement into St. Mary Bay
and a concentration at the head of it thus occurred in June.
No further recoveries have been recorded from the
1959 and 1960 taggings.
No. 51
HERRING SPAWNING SURVEY
R. A. McKenzie
In the western North Atlantic little is known of
the size of the herring spawning stocks, the distribution of
the spawning grounds and density of the eggs on them or the
production of larvae from the various spawnings.
Preliminary studies off southwest Nova Scotia in
1960 failed to locate any actual spawning grounds though small
draggers reported herring eggs in their trawls.
A search in the same general area' during the first
week of September 1961 revealed two separate spawning grounds,
one of which was accurately located and its area determined.
In surveying the ground, bottom collections were made outward

- 109 - Herring (Pelagic)
in all directions from a buoy dropped on first locating herring
eggs. The area, about 81,000 sq yd in extent, was very roughly
tear-drop sha~ed with the eggs concentrated at the apex in a
layer up to lt inches thick. The bottom was fairly flat, consistin~
chiefly of fine black gravel with some loose stones and
small rocks. It was located about li miles off Black Point
near Cape St. Mary in 7 to 8 fm of water. Sampling at close
intervals made it possible to delimit the areas with different
thicknesses of eggs. Counting the eggs in various small
samples of the egg sheets showed that an egg sheet a foot square
and l/8-inch thick contained about 12,200 herring eggs and that
there must have been about 17t billion eggs on this small grorthd.
Herring eggs, Black Point, N.S., 1961
To date no work on the fecundity of Bay of Fundy
herring has been conducted. European investigators have found
that there may be over 100% variation in the number of eggs
in herring of the same average length but of different origins
and times of spawning.
Using the relationship between fecundity and length
fQr northern North Sea herring the females spawning off southw~st~rn
Nova Scotia in August and September 1961 have been
calculated to have about 107 thousand eggs each. Using values
tor Norwegian spring spawners there would be only about 41
thousand eggs. In the first case (assuming a 1:1 sex ratio)
tqe school which spawned off Black Point consisted of about
325 thousand individuals (75 tons) wpile in the latter case
there were about 850 thousand individuals (200 tons).

Herring (Pelagic) - 110 -
The second spawning ground found by small dragger
fishermen was only a half mile from the first but definitely
separate from it. The bottom in this case had a luxuriant
growth of coarse, brown (autumn characteristics) Desmarestia
aculeata to a depth of 3 to 6 ft. This growth was covered
with herring eggs so that the small draggers reported that the
herring eggs were "a fathom deep in that patch of cmares'
tails". Samples were obtained from the fishermen but it was
impossible to investigate this ground further.
No. 52
HERRING LARVAL STUDIES
R. A. McKenzie
Herring fisheries are carried on in various areas
along the Atlantic coast of Canada. The irregularity in the
distribution of catches and the seasons of maximum availability
suggests that there are different stocks or populations
of herring supporting these fisheries. It is important for
yield predictions to know the origin of the fish in the
various populations and the method of transport to the fishing
grounds. Because of this studies of the breeding grounds
and nursery areas have been instituted and surveys of dispersal,
survival and growth of larvae have been carried out.
These investigations are programmed jointly with Biological
Oceanography for studies of the physical environment and
especially the directions and speeds of non-tidal surface
currents that are mainly responsible for the dispersion of
herring larvae (Appendix No. 82).
Gulf of St. Lawrencee Since 1951 plankton
collections have been made annually in the Gulf of st.
Lawrence for studies of the abundance and distribution of
lobster larvae (Appendix No. 3). From 1952 to 1957 inclusive
random samples of these collections were examined
each year for herring larvae. In 1951 and since 1957 all of
the tows were examined and the numbers of herring larvae
recorded.
By far the greatest numbers of herring larvae were
taken from mid June to mid July although tows were made from
mid May to early November. No larvae were caught before
June 15 or after September 30 in any year. The accompanying
table gives the average number of larvae per tow for two
periods each year. The separation of tows before and after
July 15 was made on the assumption that larvae caught before
July 15 were the result of spring spawnings whereas those
caught after July 15 were the result of summer spawnings.
Most of the larvae taken were small ( ( 20 mm) indicating
a fairly recent hatch. The table shows that the greatest
numbers of larvae per tow were taken in 1952, 1953 and 1955

co lll - Herring (Pelagic)
in that order. Since 1952 the numbers caught before July 15
have declined irregularly to an all~time low of 0.2 larvae per
tow in 1961. Since 1956 there has been some tendency towards
an increase in the numbers or larvae taken after July 15.
The high a\TFrage for 1961 is the result of large numbers of
larvae in a few tows but some larvae were taken in an unusually
large number of tows that year. This may indicate
a ehange in herring spawning habits in the Gulf of St. Lawrence
and there is other biological evidence (Appendix No~ ~) to
support this conclusion.
Gulf of Maine-BaY of fundyo Two cruises were carried
out in the Gulf of Maine in Octobero While these cruises were
mainly concerned with exploratory fishing for adult pelagic
fish~ plankton collections were made and some herring larvae
were caught. Twenty-two tows during the first half of October
Average catch of herring larvae in Northumberland Strait,
1951-6lo (Numbers of tows in brackets.)
Ayerage catch per tgw
Year June 16-July 15 July 16:Sept.30
------·-----------------------------------------------------
1951
1952.
1953
195lf
1955'
1956
1957
1958
1959
1960
1961
74.6 (125)
1,897o8 (42)
855.9 (35)
127. 1 + (36)
4o7.8 (!i-6)
31.6 (54)
32.5 (73)
9.1 (186)
1. 5 (154)
11., 6 (182)
Oo2 (175)
o.o (213)
0.2 (61+)
o.o (68)
o. 2 (82)
o.o (50)
o.o (87)
1.1 (77)
o.o (294)
g:t ~~~~
19•3 (293)
yielded only 4 larvae (12.3 mm average length) all on the
northeast edge of Georges Bankiwhile during the last half of
October an equal number of col ections yielded 1 larva
(13o0 mm) off Grand Manan, 16 (14o5 mm average length) between
Yarmouth and Browns Bank and 49 (13ol mm average length)
along the northern edge of Georges Bank.
Fourteen cruises (January through December) for
lar·~ral herring in the Sto Mary Bay area combined with 4 (July,
August and November) across the mouth of the Bay of Fundy
and 1 cruise (July) covering the whole of the Bay of Fundy
indicated that heavy concentrations of larvae occur only in
the St. Mary Bay region and its approaches. A peak in
abundance was found in and near St. Mary Bay during MaY when
the larvae were 30 to 4o mm longo In July smaller concentrations
were found in the Sto Mary Bay area, at the head of

Herring (Pelagic) - 112""
the Bay of Fundy and in Grand Manan Channelo The average length
of the larvae in July increased from about 17 mm in St. Mary
Bay to 40 mm at the head of the Bay of Fundy and to 70 mm (postlarval)
in Grand Manan Channelo Newly-hatched larvae app~ed
in August mainly in the Sto Mary Bay region~ reached a peak in
abundance in September (see accompanying figure) at lengths
of 10 to 12 mm and declined by December when they were 20 to 30
mm long. The collections in Sto Mary Bay in the autumn of 1961
yielded only about 1/lO as many larvae as in 1960 •
•
av.---- ~·~,~=~
. . e
•
•
•
•
•
(100 .,. •
100-500 -.
500-900 --
Herring larvae distribution in the Sto Mary Bay
area in September 196lo
Day and night collections were compared in January
when a night cruise in Sto Mary Bay was conducted following
a day cruise--the night cruise yielded 12 larvae (32 mm average
length)~ the day only 3 (28 mm average length).
He~ring larval collections were made both with
l~metre plankton nets (about 25 meshes to the inch) and Isaacs­
Ki.dd trawls with a codend of approximately the same size mesh
opening. In every case the larvae were 10.% :_to 100~( larger in
average length from the Isaacs-Kidd trawl. In St. Mary Bay
the lar·vae wereusually larger in the inner part of the Bay.
When they were abundant in the Bay there was a definite
"stream" of larvae out through Petite Passage and up along
the Nova Scotia side of the Bay of Fundy. Larvae collected
with beth types of gear at depths from 0 to 25 metres showed
no consistant pattern in depth distributiono
Mr. c. A. Dickson carried out the examination of
plankton tows and the sorting, counting and measuring of herring
larvae.
S. N. Tibbo
R •. A. McKenzie

No. 53
.., 113 - Herring (Pelagic)
HERRING FISHERIES OF THE WESTERN GULF OF STo LAWRENCE
M. H. Perley in 1852 indicated that there were myriads
of herring in the Gulf of St. Lawrence and from 1920 to.the
present the average annual catuh in the whole Gulf of St.
Lawrence has been about 80 to 85 million lb~ about 15% to 18%
being caught off the Newfoundland west coast.
During the Atlantic Herring Committee Investigations,
1944-50, it was found that these fj.sh existed in more or less
distinct popUlations. Figures lA and B show that in the western
Gulf of St. ~wrence the herring landings were made in three
main areas, Bay Chaleur, western end Nor·thumberland Strait, and
the Magdalen Islands. Only about 7% of the western Gulf herring
catch was made north of Cape Gasp6 while 35% was landed in and
around the mouth of Chaleur Bay from Cape Gasp~ to Escuminac
Point. The western end of Northtunberland Strait including
Prince County, P.E.I.l yielded 31.% while the eastern end of
P.E.I!J. Northumberland Strait and western Cape Breton produced
only 'fo• The remaining 25% of the herr:·i.ng landings in the
western Gulf came from the Magdaleno.
Figure 2 shows that the total Canadian Atlantic
herring landings increased from 200 to 250 million lb in the
early l~O's to a peak of over 400 million lb in 1946 and then
declined to the early 194o level where it has remained since
1953. High landings in Newfoundland and the Bay of Fundy
were mainly responsible for the peak in 19l~6o In the western
Gulf of St. Lawrence landings from 194o to 1955 increased
irregularly fromabout 70 to 90 million lb and then declined
to about 40 million lb in 1961. The trend in the Magdalen
Islands landings roughly followed that in the western Gulf.
Landings in the Chaleur Bay area dropped fairly steadily from
about 35 million lb in the early 1940 1 s to about 15 million
lb in the late 1950•s. Widespread mortality in the Gulf in
1954 and 1955 no doubt contributed to the recent decline in
landings. The lov point was in 1959 and there was some
evidence of recovery in 1960 and 1961.
In recent years herring investigations have been
centered in the Caraquet area at the mouth ot Chaleur Bay
and at the Magdalenst since the populations in these regions
have yielded about 3'% and 25% respectively or the total
herring catch, in the western Gulf of St. Lawrence.
Of all fish landings in the ChaleUr Bay area about
35% by weight are cod while herring rank second making up
ab~ut 20%. However, in value herring make up only about 5%
with cod, lobsters, smelt and salmon giving greater monetary
returns.

Herring (Pelagic) - 114 -
A
62°
Fig. 1. Herring landings 1920-59; • = 250,000 lb.

- 115 - Herring (Pelagia)
·- Can • .at1.autic total (inc).ud. Nfld.)
·---· Gulf of St. Lawrence .( exclud. Nfld.)
X···· .... " Magdal ens
X-X Baie Chaleur region
300
I
80'-
60-
./
I
1\ I
I \ I
• / \ I
\ 1\ ;--• \ I
I \ 1 \I
\ I \
\ • \ I
I • I
\ I ', I
. I '•
/
,,
/ \
/ \
'
..
1\
I I
.
I
I
I
I
I
"'
I
I
I
I
. ' '· '
~
40-
20-
.X " )( • •• t.'
•' • •••)(••• •n•••• •
# ••""·. • •
)(' ... ·X •••.""J·
··x·
~--:f .
, . .
,.'
: "
'x
'
~
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•'· •
,' . , .
; k ..•.)f
, ·.
: '·. ·. .
' '•
' ' '· ' ' ' •
' '
lt
••
.....
\
' ' •
1940 '50
'55
'6o
Fig. 2. Herring landings, Canadian Atlantic; preliminary
figures 1960+.

Herring (Pelagie) = 116
At the Magdalen Islands, landings by weight and
value for 1953-58 inclusive show that on the average herring
make up about 65% of the landings by weight but only 9~ of'
the value. Lobsters (59%) and cod (22%) rank first and
second in value ahead of herring. While these figures show
the importance of herring by weight and in dollars it does
not bring out the fact that herring serve as the main source
of bait and without these fish~ especially on the Magdalens,
the landings of most other species might be drastically reduced.
The western Gulf of St. Lawrence herring fishery is
seasonal beginning in April~ reaching a peak in May, dropping
sharply in Junes then declining gradually to about zero by
December. However, at the mouth of Chaleur Bay there is an
autumn fishery giving a secondary peak in September and October.
These peaks in the fishery are associated with spawnings in
both spring and autumn&
Years ago fleets of herring gill-netters visited
the Gulf of St. Lawrence 9 particularly around the Magdalena.
Chaleur Bay,
This is now a thing of the past.. orr Caraque~ 1
most of the herring are taken in anchored gi~ nets 1 while
on the Magdalens traps are used chiefly. ~hough 200 to 4oo
gill nets have been licensed annually at the Magdalens in
recent years 9 90% to 95~ of the herring catches have been made
in the trap nets. ·
In the Chaleur Bay area the fishery is located in
the outer part of the Bay 9
especially in the Shippigan~Miscou
Islands region. At the Magdalens it takes plac~ mainly in
the bight between Grindstone and Amherst Islands. About 40
trap .sites are registered, 15 off the northeast end of Amherst
Island: 20 off east of Grindstone Island and 5 in Grand
Entry Harbour. These 25-4o fm diameter heart-shaped traps
have leaders 50=250 fm in length and are set along shore in
1-5 fm of water~ held in place with anchors and supported
by buoys.
Large quantities of the herring caught in both areas
are used as bait tor lobster traps and line-trawlso However,
in the Chaleur Bay area a large part of the catch is processed
into pickled products and fisn meal while on the Magdalens
smoked herring is the chief' food product.
No. 5lt
GULF OF ST •. LAWRENCE HERRING POPULATIONS
R. A. McKenzie
Studies of the biology of herring populations in
the western Gulf' of' St. Lawrence were·continued in 1961.
Samples of' herring were obtained f'rom ancpored gill-net

- 117 - Herring (Pelagic)
landings at Caraquet, N. B., in May and August-September, and
trap landings at the Magdalen Islands in May. Five to six
hundred fish were sampled from each area, consisting of subsamples
of 100 fish from as many landing points within the
area as possible. The samples were examined for total length,
sex and maturity of the gonads, and otoliths were extracted.
The otoliths were used to determine age, growth season,
hatching season and 1st-year growth.
Length and age. The accompanying figure shows the
length and age frequencies for the three series of samplei.
The mean length of 31.4 em found for the May samples from
Caraquet was the same as that for 1960. The mean age was
5.72 years as compared to 5.67 years in 1960. For the autumn
samples from Caraquet the mean length was 33.2 em and the
mean age 6.51 years. In 1960 mean length and age were 33.7
em and 7.08 years respectively. The samples from Magdalen
Islands were taken at the end of the fishing season and 90%
were sexually immature. The mean length was 24.6 em and the
mean age 3.02 years. No samples were obtained from Magdalen
Islands in 1960. Samples taken in earlier years consisted
mainly of spawning fish, and hence should not be compared
with the 19ol samples. Compared with results of previous
investigations (1946-48) mean lengths for both spring and
autumn samples from Caraquet are unchanged but mean ages
have decreased by approximately 1.5 years. This suggests an
increase in growth rate in that area •.
Year-class abypd~nce. Both the spring and autumn
fisheries at Caraquet were dominated by fish of the 1956
year-class (age 5J. By comparison, in the 1960 samples the
195'lt and 1955 year-classes were most abundant. At Magdalen
Islands the 1957 and 1959 year-classes were dominant. The
main difference between the Caraquet spring and autumn
fisheries was the presence of larger numbers of older fish
and more year-classes in the autumn.
Maturity. About 95% of the fish in the samples
from Caraquet were in the maturing or ripe and running stages,
mainly the latter, suggesting that the peaks of the spawning
seasons were late May and early September in 1961. About 90%
of the Magdalen Islands fish were immature but would probably
spawn the following year.
Growth and hatching seasons. Differences in
otolith characteristics were used to dete~ine growth and
hatching seasons. During the growing season the edge of the
otolith has an opaque appearance otherwise the edge is hyaline.
Otoliths of both fl)ring and autumn samples from Caraquet and
spring samples from Magdalen Islands showed hyaline edges
indicative of no growth. Thus, the annual growing season for
these areas is probably between late May and late August.
Both the appearance ·of the otolith nucleus and the width of

7~
15
lOr-
5[
%!
15
10
5
%
15
/I
/' CARAQ1JET (SPRING)
• \/ (500)
'\ .
\
........
CARAQUET (AUTUMN)
(600)
.
. /\
/ 1-•-........
I ·-\,_
........
MAGDALEN IS. (SPRING)
(600)
40
zo
0
40
20
0
40
(500)
(600)
(600)
::r:
(!)
'i
'i
r'·
1:::'
()\:I
,.-....
~
(!)
1-'
P'
()\:I
1-'·
0
'-'
1-'
1-'
CX>
1:- /\ ;-\
% v ·-·-·-· \
20
•
25 30
Length (em)
I
35 40
20
Length and age frequencies.
I I I .
. I
'60 ., 58 '56 ' 54 '52 '50 '48 • 46
Year-classes
•
I
•-

- 119 - Herring (Pelagic)
the 1st-growth zone were used to determine hatching season,
The otoliths of spring-hatched fish have domed, opaque nuclei
whereas those of autumn-hatched fish have depressed, hyaline
nuclei, Autumn-hatched fish usually do not produce a winter
ring in the otolith during their 1st year and hence will have
a wider 1st-growth zone (01) than fish hatched in the spring.
Distribution of hatching types and mean 01's (in eyepiece units)
for herring samples from Caraquet and Magdalen Islands 1961,
---
C~r~gyet Ma.g!la.l!i!n l ~h
Ma.I tug1 -Se:Qt 1
M~Y
~ Mean 01 ~ Mean 01 ~ ""ean o 1
Sprj_ng hatched 73 19
24 54 20
Autumn hatched 27 21 25 46 21
~~
The proportions of the spring- and autumn-hatched fish in the
three series of samples and the mean widths of the 1st-growth
zones are given in the accompanying table. The table shows
that spring-hatched fish dominate all three fisheries and
particularly the spring fishery at Caraquet. The differences
in mean o 1 vs for Caraquet samples suggest that fast-growing,
spring-hatched fish tend to become autumn spawners while
slow-growing, autumn-hatched fish tend to become spring
spawners.
No, 55
EXPLORATIONS FOR PELAGIC FISH 1961
T. R. Graham
During the latter part of August and throughout
October, exploratory-fishing operations were carried out in
the offshore waters of the southwest Canadian Atlantic area
in an attempt to discover concentrations of pelagic fish
(herring, mackerel, tuna, swordfish, sharks, etc.) that
might be available for commercial exploitation, The areas
of operation included Georges Bank, Browns Bank, Bay of Fundy,
Gulf of Maine, and the western edge of the Gulf Stream.
Fishing was done with mid-water trawls, bottom trawls,
Japanese tuna gear, handlines and drift gill-nets. Temperatures
and salin:Lties were taken at all fishing stations. In
areas of known herring spawnings, plankton tows with 1-metre
nets, Isaacs-Kidd trawls or Gulf III sampler and drift-bottle
releases were made, The Harengus was used for the August
c~ise and the A.T. Cameron for two cruises in October. A
total of 1~ stations were occupied for various purposes during
the three cruises.

Herring (Pelagic) .. 120 -
Results8
(a) Mid-water trawls. Duripg the August cruise a
Swedish type mid-water trawl with a '+8-ft square opening was
used four times on the northern edge of Georges Bank. In
October it was used twice on Georges Bank, once off southeastern
Grand Manan and once at the edge of the Gulf' stream.
The only catch (except for three 10-13 em sardines off Grand
Manan) was 1~ lb of large, sexually mature herring taken in
one tow on Georges Bank in August.
(b) Bottom trawls. Dutch herring trawls were used
from the Harengus and 41-5 trawls with a small mesh (lf inch)
lengthening piece and codend from the A.T. Cameron. Seventeen
sets on Georges and Browns Banks in August produced mostly
groundfish species in amounts varying from 100 to 6oo lb per
tow o Only 4 herring were taken in 8 tows on Browns Bank and
only 13 in 9 tows on Georges Bank. Some herring were taken in
8 out of 11 tows on Georges Bank in October but the largest
catch was only 3i baskets (ca. 350 lb) 1n a 60-minute tow.
In bottom trawl sets on Browns Bank (3), at the entrance to the
Bay of Fundy (3) and in Passamaquoddy Bay (1), groundfish species
(chiefly haddock) dominated the catches which varied from ca.
500 to 3 ,ooo l'b per tow.
(c) Japanese longlines. Longline fishing on Georges
and Browns Banks was relatively successful in all three cruises.
The usual practice was to set the gear at night and haul back 1n
the morning. Only one day set was made. The number of hooks
used for each set varied 10 to 112 and herring, mackerel, squid
and small haddock were used for bait. In August three sets took
a total of 33 sharks (31 blues and 2 mackerel). In October there
were six sets on Georges Bank, two off southwest Nova Scotia,
one on Browns Bank and two in the Gulf Stream. Total catches
amounted to 130 sharks (94 blues, 35 mackerels and 1 white tipped)
and 2 bluefin tuna.
(d) Drift nets and handlines. One drift gill-net set
was made near the edge of the Gulf Stream. Mesh sizes varied
from 2! to 8 inches stretched measure. The catch was nil.
Handlines were used on 14 occasions when the vessel was stopped
for othe~ purposes and 1 mackerel shark and 10 blue sharks were
caught.
Results of other operations which included drift-bottle
releases at 62 stations; Isaacs-Kidd trawl tows at 35 stations;
1-metre plankton net tows at 20 stations; B.T. observations at
96 stations and temperature and salinity observations at 80
stations are reported elsewhere.
Earlier cruises have shown spawning herring concentrated
along the northern edge of Georges Bank during late August and
early September. The october 1961 cruises demonstrated the
presence of herring (in smaller quantities) much farther westward.

- 121- Herring (Pelagic)
Although the 1961 cruises were made primarily to determine the
distribution of pelagic species with possible commercial value,
opportunity was taken to improve the teclUlique of tagging large
fish by tagging and rel~asing 10 sha?ks. Perhaps the most significant
result of all three cruises was the availability of
mackerel sharks for which there is a gcod market demand. Catches
on Georges and Browns Banks were approximately 10 mackerel sharks
(average dressed weight 177 lb) pe~ 100 hooks set.
No. 56
SWORDFISH INVESTIGATIONS 1961
S. N. Tibbo
A study of swordfish and tD

\
\
~
..
I
0
...... '•
... ·. . . :
. :
• • •
.
... _
. . .
. .
• ,., • •r
:;""': \"' _._.S 0
Sable ('\ 'tl
. ~ ~ -b\,J~~ • ~·-.. :··, ............... ··•
,.. ~ . . . . . .
: \_ '; ~ .. 0 0 • • • I
; ····-.. \ 6 •• 0 0 .·' ..........
. . .....
• • •
. ... . . . ..
• ·~ : •••• ...•• · .. . . .·
• •• ••• •••••••••••••• .... :.
••
..: ·..· ·.....·
••••
(j"'
. ............. ..• . . .. ... ..· ..... ·•· .
Georges . e e e· e
Bank ......
' ..
,l
••
............
.
;0. ··..
. .
.. . ...........
.•. ·. .
... .. : .....
:. 0 (25,000 1b
• 25,000 1b
. .
···:
••• •••
•
• •• ~N~
~
(1)
li
li
f-1·
I:!
~
,--....
1-d
(1)
f-J
Ill
~
f-1·
0
...__,
f-J
N
N
Fig. :1. Distribution of swordfish catch, 1961.

- 123 - Herring (Pelagic)
15
1-
r--
r--
1,559 swordfish
Av. wt. 196.42 lb
~ 10
Q)
0
~
Q)
Pot
5
f-
f-
r--
.---
...--
r--
...--
,....-- r--
r--
-
0
r-1
50 100
n.,r-1 11,.......,
-150 200 25 0 300 3~ 450 500
Weight (dressed) in pounds
Fig.- 2. Weight, distribution of swordfish, 1961.
400 1,152 swordfish
,-....
rc:;
Q)
m
Cll 200
t!
rc:;
40 50 6o 70 80 90
Length (dressedJ in inches
Fig. ). Length-weight relationship of swordfish.

Herring (Pelagic) .. 12l.f. -
fully occupied with·svordf1sh-t1shing from June to September
were used. Man,- 'Yessels are tnaaged 1n mixed fishing during ·
which they catch swordt1~h altag·with halibut or other groundfish
speeieso The records fr•• these vessels are included in
the catch distribution f'igure.but not 1n the table. It should
be noted that the data originally recorded for 1960 has been
adjusted to comply with the abeve standard.
'
Summary of swordfish log reco~ds 1959-61.
Total no. of trip records
Total no. of days at sea
Total no. of fishing days
Total no. of fish caught
Total weight of fish caught
Av. no. days at sea per trip
Av. no. fishing days per trip
Av. no. fish caught per day at sea
Av. no. fish caught per day fishing
Av. no. fish caught per trip
Av. landing per trip (lb)
Av. ann. landing per vessel (lb)
Av. gross stock per trip (dollars)
Av. ann. gross stock per vessel
1959 1961
There were only minor differences in the success of fishtnc
in 1960 and 1961 as shown by the average number of fish caught,
the average landings per trip and per vessel, and the gross stock.
In 1959 1 however, although the fishery was much more successful in
terms or number of fish landed, the earnings per vessel were considerably
lower.
Biological studies of swordfish were concerned chiefly
with length and weight data by months and from the various fishing
grounds. Attempts were made to add to our knowledge of food and
feeding habits but all of the material obtained was in such an
advanced state of digestion that it was impossible to identify
any of it. It is obVious that food studies must be carried out
at sea rather than by bringing preserved material ashore. Lencth
and weight data were obtained from commercial landings after the
fish· had been dressed. Swordfish are dressed at sea and measurements
of whole fish are rarely possible. During the 1961 season,
lt559 swordfish were weighed and the resulting weight distribution
is shown 1n Figure 2. Individual weights ranged froa 60 to ~19 lb.
The mean weight was 196.4 lb (210.9 lb in 1960) with the median
occurring in the200-lb class (188·212 lb) • Examination of results
by areas showed a weight difference or 30.1 lb between swordfish

- 125- Herring (Pelagic)
caught on Georges Bank (mean weight 195.1 lb) and those caught
on Sable Island Bank (mean weight 225,2 lb). Results of sim~lar
studies in 1960 gave no indication of any size difference tor the
various fishing areas. On a time basis the data for all areas
combined showed an increase 1n mean weight from 179.8 lb tn
early July to 201.0 lb in mid August. A similar size difference
was found in 1960 but the actual size was larger (203 lb tn June
and 226 lb 1n September).
There were 1,152 swordfish for which both length and
weight data were obtained. These data were ~~otted to show a
length-weight relationship and are given in Fia~e 3. The
results confirm the validity of a Similar length-weight curve
obtained 1n 1960 from a smaller sample.
s. N. Tibbo

'!'ROUT SUMMARIES
Number
Limnological and trQut investigations
general statement 57
Annual fluctuaticns in standing crops of
brook trout !n El~erslie Brook, P.E.I.
Page
127 - 128
58 128 -
Physical alterations of stream environments
to improve brook trout production
and utilization 59 129 - 131
Yields of brook trout from natural and
artificial recruitment 60 131 - 132
Estuarial stocking of brook trout 61 132 - 133
Distribution of brook trout and immature
salmon in relation to their numbers in
a stream 62 133 - 13~
Relative value of rainbow and brook trout
in utilizing the productive capacities
of Maritime fresh waters 63
134 - 137

------~~-~--

No. 5"'1 - 127 - Trout
~IMNOLOGICAL
{TROUT) INVESTIGATIONS
GENERAL STATEMENT
Limnologica~ survey has been sufficient to zone
Maritime freshwaters with respect to their productive
'1apacities.. Most Maritime lakes are associated with-igneous
rock formations. Their waters are poorly mineralized, with
low· to mediocre productive capacities. In contrast' streams
that drain areas of sedimentary rocks with a good lime content
are often highly productive of trout foods and trout. The
principal experimental approach toward greater trout production
in any of these ~~o~Taters has been to alleviate natural
deficiencies by manipulation of environments and of fish
popu1.ationso Concern has also been with effective cropping of
fish tuJ.cler both improved and existin.g natu!'al conditions, as
well as w:i.th rehabilitation of habitats damaged for fish
productiou. by man's activities ln l..'.Se of water and land.
Research programs have dealt with stocking of indigenous
ar:d non-indigenous species, destruct~io:'l. of undesirable fish,
predator control, fertilization of nat·t:t.ral waters, control of
movemE:nt~l of brook trout, pond formation. Results have been
sufficiently positive with respect to stocking, predator control,
fe:rtil.izat.:L,...m and pond formation to indicate feasible and
effective ~pplication in many Maritime freshwaters.
Investigations in progress upon effects of forming
a pond on P:;.~ince Edward Island trout streams show that because
of retention and accumulation of fish in the pond, anglers•
catches are initially improved then decline to a level su.stained
by the a...'Ulu.al recruitment of trout of catchable size from the
trlb1;j, taries (Summary lio. 59). Physical a1 tara tion of stream
habi ta·ts to p:i."'ovide more living space il'lcreases standing crops
of young trout, but it b;ts not yet been established whether
axm:u.al :recruitment to the pond will thereby be materially
increas(~d (Su.mmary No. 59) o Hatchery-reared trout (age 0)
survived poorly in an unfished pond~ and did not increase the
standing crops previously realized only from annual recruitment
of nat~~.ve trout from the tributary (Summary Noo 60). Annual
rather than biennial cropping of native recruits to a pond gave,
on the basis of a yearly average, higher yields of trout by
weight .•
Pond formation on Ellerslie Brook markedly reduced
the number of brook trout run from the brook into the estuar1
and contiguous marine areas. In an attempt to replace the
former recruitment from Ellerslie Brook to these areas, marked
hatchery·~reared brook trout were planted directly into the
estuary in early winte!", 1962 {Summary No. 61) o The planted
tro11t were of a size at which they have been shown experimentally
to adjust to estuarial conditions$
Gur:i:-ent studies show tha·~ sea-run
to a. PrJ.n.c:e Edward Island stream are poorly
because they soon become distributed i~ the
rela.t:l.ve] .. y m2f'ished areas (Summary Noo 59) o
fish in rea :lily accessible areas to a.Y).glers
brook trout returning
cropped largely
less accessible,
Retention of sea-run
by temporary barriers

Trout - 128 -
is indicated as a procedure for more effective croppingo
Results to date from a continuing experiment show
that the non-indigenous rainbow trout and indigenous brook
trout, when not in competition with each other, utilize and
survive in a New Brunswick lake habitat to provide about equal
yields to anglers (Summary Noo 63)o · In a Prince Edward Island
pond, with competition between them, the rainbow trout appears
to dominate, and would possibly supplant, the brook trout with
opportunity for equal recruitmento
No. 58
ANNUAL FLUCTUATIONS IN STANDING CROPS
OF BROOK TROUT IN ELLERSLIE BROOK9 PoEoio
M. W., Smith
As part of a study to determine the effect of a dam
on the population of trout in Ellerslie Brook~ an annual
summer assessment of the stream population was begun in 19~7
and has been continued through 196lo Trout are counted in a
number of 5~yard sections of Ellerslie Brook and in a ~50-yard
section of the tributary~ Hayes Brooko
Climatic and environmental factors have contributed
to observed fluctuations in standing crops over the yearso
Annual variations in numbers were greater in the larger pool
habitats than in the smaller? more stable habitats. Changes
in amount of cover haa a marked effect on the trout-carrying
capacity of some areas of the streamo Because of the limited
trout-carrying capacity (this varies annually and seasonally)
of the stream~ annual fluctuations in numbers of underyearlings
were not comparably reflected in numbers of yearlings and older
trout. Survival of marked older trout (ages I and II) to the
same area the next year has varied from less than 2 to 1~%.
Effect of pond formation
Following the formation of a pond on Ellerslie Brook
in late summer of 1952~ most of the trout age II and older moved
into the pond in autumn or springo There has been little return
movements from the pond into the streamo Consequently, the
stream populations of trout in the years following pond
formation has consisted 1 for the most part, of fingerlings
(age 0) and yearlings (age I)o The reduction of older trout in
the stream after pond formation did not have any apparent
effects on stocks of fingerlings (age 0). They continued to
remain at, or higher than, pre-pond levels. Older trout stocks,
consisting largely of yearlings (age I), have also remained at
pre-pond levels., The loss of the age II and older trout to the
stream has been compensated for by a better survival of
fingerlings to the stream as yearlingso
J" Wo Saunders

Non 5'9
- 129 -
PHYSICAL AI:rERAT IONS OF STREAM ENVIRONMEN.rS
TO IMPROVE BROOK TROUT PRODUCTION AND UTILIZATION
Trout
Alterations of stream environments herein considered
are: (1) pond formation, (2) provision of more living space and
hiding places by building low barriers and adding cover and (3)
temporary barriers to control upstream movements of trout for
retention in areas readily accessible to anglers.
1. Pond formation on Ellerslie Brook, P.E.I.
·-·- .·
Ponds formed on Prince Edward Island streams provide
good angling f'or brook trouto Brook trout move between fresh
and salt water in the Prince Edward Island area. A 5'-acre pond
was formed on the lower reaches of Ellerslie Brook in 195'2 to
study pond formation as a management procedure to improve
production and yield of trout to anglers from a stream system-­
stream9 pond and estuary. Year-round operation of two-way fish
traps above and below the pond, tagging of individual fish, an
annuaJ. creel census and annual population assessments of tne
brook population (Summary No. 5'8}, provide data to judge the
effects of pond formation. Trout entering the brook from salt
water were transferred to the pond until December, 195'5', but
thereaf•ter excluded.
Pond formation markedly reduced the number of trout
moving to salt water. Comparative data are: average annual
number for five years prior to pond formation, 1,775 trout;
for eight years after pond formation, 311.
The annual fishing effort and annual catch of trout
were increased appreciably during the early years after pond
formation (Table I). The majority of the trout were captured
in the ·por.. d and pool ·below the dam. At the close of the
angling season of 195'8, the pond was drained and only 73 trout
were found~ indicating that cropping by anglers was nearly
complete. In later years both effort and catch have fallen to
pre-pond levels. Angling statistics, movements of trout
through the traps and assessment of population in the stream
indicate that the catch is largely maintained, with the level
of effort involved, by the annual recruitment of trout of
catchable size.
Pond formation improved the catch of trout from the
Ellerslie system in part by holding the trout in the readily
accessible pond and pool areas, but the improvement was shortlived.
The potential of the pond as a rearing and holding area
was not realized with the recruitment possible from the
tributary stream. Additional recruitment to the Ellerslie
system is being attempted by stream improveMent to increase the
carrying capacity for young trout (see below} and by stocking
the estuary, which now has a relatively small population of
trout (Summary No. 61). The low catch in 1961 is in large part
ascribed to the. unusual drought conditions in 1960 which had
adverse ef·fe{;ts upon the stream population of young trout.

Trout
Tab1e Io Yield of brook trout to anglers fran the Ellerslie Brook system,
PoE. I.
lo
Before pond fonnation
Average Average annual Average ammal.
annual catch effort 1
rod-hours catch E!r rod-hour
1947-52 1,478 812 1.8
2. Af'ter pond formation
Total Total Catch Catch fran Catch
catch rod-hours per rod-hour pond and pool fran stream
1953 1.,981 1,325 lo5 1,843 138
1954 2,949 2~452 lo2 2,343 6o6
1955 1,n8 1,676 1.0 1,126 592
1956 2,047 1,6o5 1.2 1,554 493
1957 1,677 1,259 1.3 1,348 329
1958· 1,229 1,011 lo2 553 676
1959 1,222 925 1.3 958 264
196o 1,448 987 1.,5 863 585
1961 734 535 1.4 495 239
2. Stream improvement, Ellerslie Brook
Studies on Hayes Brook, tributary to Ellerslie Brook,
Prince Edward Island, showed that availability of suitable
hiding places is a dominant factor in limiting the numbers of
yearling trouto To overcome this habitat deficiency, the
stream environment was altered by means of low dams, deflectors
and covers, to create conditions known to be favourable to
trout production. After one year the numbers of yearling trout
in a 450-·yard study area were about double the average of the
numbers in the area over the previous 13 years.
Because of severe drought conditions during 1960
and 1961, stocks of yearlings in both Ellerslie and Hayes
Brooks were lower than those recorded in 1960o HOwever even
under adverse conditions, the yearling trout stocks in ~yes
Brook in 1961 were higher than any recorded in the years prior
to stream improvement.
On the basis of our findings in the tributary Hayes
Brook 1 a more extensive stream improvement programme was begun,
in 19ol, on Ellerslie Brook proper to learn if this procedure
will effectively provide more recruits to the pond. To date,
19 low dams have been built in the lower 2000 yards of the
streamo The construction phase of the programme should be
completed during the summer of 1962o

- 131 - Trout
3 0 Retent-ion of brook trout in areas aCC§SSible ~f? 'r~lers
The majority of trout .that enter Prince Edward
Island streams from salt water (in ~verage they are the older
and larger trout in the ·system) ·move well upstream into areas
poorly accessible to anglers. More effective cropping of these
trout might be expected if they were held by tempora:ry_ barriers
in readily accessible areas near stream mouths. ·
Preliminary studies without barriers ar$ being made
at Cain~s Stream, P.E.I. upon the extent to which the s.ea-run
trout are t!ropped by anglers, and their contribution, ~.q the
anglers u catches from the stream. A two-way fish t:ap is
operated at the head of tide, trout moving through a.;s,. t§lgged,
and a creel census is maintained on the stream .. _ Daea 'fOr 1960
and 1961 are given in Table II. The low number of trout moving
into the stream? particularly in 1961, reflects unusual low
water conditions. Sea-run trout were poorly croppedc·-~d. ni$.de. ·
minor contributions to the anglers' catches. , ···. , ·. ·
'!'able IL '!'rout running into Cain's stream fran salt water, and theif' ..
contribution to anglers' catches (Jtme - September). _· · · _.
5 . '·
196o
1961
Number Total catch Number or % angliDg ·tj, :.or se~
moving or trout sea-run trout mOJ,"taJ.ity ol run troUt in
into 'stream in stream in catch sea-run trout ·total. eateh
585
83
495 87 15 18
525 J.5 18 .3
No.
6C
YIELDS OF BROOK TROUT FROM NATURAL . ··
AND ARTIFICIAL RECRUITMENT
·M. ~. Smith
J •· v. ·Saunders
September standing crops of brook trout ha~e been
assessed for a 6.3~acre artificial pond (Stevensqn's) formed on
a Prince Edward Island Stream. The standing crops'~e~ulted
from natural annual recruitment f'rom the tributary~stream (a)
without a population of trout in the pond (b) with surviving
recruits from the previous year held over in the pond, and (c)
with the natural annual recruitment augmented by stocking with
hatchery-reared brook trout. Results are shown ;n Table I.
Standing crops arising from annual recruitment from
the tributary stream varied appreciably betWeen years· whether
or not trout were already in the pond. The highest standing

Trout - 132 -
~1e I- Annual etanding cropa of brook trout fran natural and art1t1cial
recruitaent in Btfvenson' 11 Pond, P. B. I.
J:veraae
weight, os ·
!otal.
Wicht, 1b
Sept. 19S8
Reeru.i ta fltca
~19S?•S8 663 4.9 18S
(634 IIAl"1ced and ntumed to pond)
Sept. 19S9
Becm1i ta trc.
atna 19S8-S9 643
Replanted 1958 309
Sept. 1960
lecrui ts trca
lltreaa 19S9-6o
(4• recowry)
1, bOS
Sept. 1961
Racraits trc.
lltNam 196o-6l 87S
Pl.airted f~rliap
. {10,000) Sept. 1960 300
(l. reC0'9817)
3 • .5
11.&
3.2
220
1la2
28S
132
69
46
21
crop, that for 1959, resulted from two years' recruitment from
the ~ributa~. However, the data show that greater
1
poundage of
trout was realized from the pond if the annual rec~itment was
harvested each year (185 lb tor 1958 plus 220 lb tor 1959 as
asainst the total of 362 lb for 1959). To improve the situation,
management, such as stream improvement to increase recruits
(Summary No. 59) and predator control for better survival,
appears indicated to realize more efficient utilization of the
pond's productive capacity. Stocking with hatchery-reared
underyearling trout did not improve the standing crops, but to
clarity the role of stocking more fully in such habitats,
introductions or hatchery-reared brook trout have been continued.
Survival rates of the introduced brook trout (same stock but at
different dena~ties) was quite com. parable at Stevenson's (3%) and
Simpson's (~.2~; Summary No. 63) Ponds.
No. 61
ESTUARIAL STOCKING OF BROOK TROUT
M. W. Smith
Pond formation at head of tide on Ellerslie Brook,
Prince Edward Island, markedly reduced the seaward run of trout
trom the brook. Accordingly, the estuary, a good growing area
tor Ellerslie trout was largely depopulated of such fish. In

- 133 - Trout
an·attempt to brine it baCk into production, hatChery trout
(2,000) were_planted directly into the estua17'.
Studies at Ellerslie have shown that few trout below
3 1/2 inches in length run to salt water. Trout make tew
movements between fresh and salt water after becoming
acclimated to 0° C. At or near 0° Cv:, there should be little
movement of planted trout from the estuary. Under simulated
estuarial conditions in the laboratory trout were able to
adapt to conditions similar to those in the Ellerslie estuary.
The 2,000 hatchery trout ~ere delivered to Ellerslie
on November 29o They were measured, marked b.r fin removal and
placed i~ cages in Ellerslie pond for fin marks to heal. The
average lencth or the trout was ~ 31~ inches.
On December 1, 975 were liberated in the tidal area
between Ellerslie dam and the estuarial counting fence. Water
tempera~re at time or planting was 2.8° c., salinity was less
than l ~o • On the same day- 975' trout were plan ted in the
estuary 265 yards below the estuarial fence. Water temperature
at the planting site was 3.0° C.; salinity varied tro• 1.3 at
the surface to 18 %. at the bottom (36"). AccordinclT, the
hatchery trout were presented with a variety ot eond1t1ons.
Caged fish (25) from each or the plantincs were held
at the planting sites. There were no deaths Up to December
16, when, because of ice formation, the caced tish were
liberated.
There was some movement in both directions throuch
the estuarial counting renee until December 2~. Evaluation ot
the stockinc as a manacement procedure will have to await the
1962 angling season (April 15--September 30).
Nco 62
DISTRIBUTION OF BROOK TROUT AND IMMATURE SALMON
IN RELATION TO THEIR NUMBERS IN A STREAM
J. W. Saunders
During the summer of 1961 the standinc crops ot trout
and immature salmon in Cain's Brook, Prince Edward Island, were
assessedo
Trout
Findings
Fingerlincs (fish of the year) varied in number trom
3 to 7 per 100 square yards of stream bottom. The total number
in 5t533 yards of stream was estimated to be 1,200. They were
founa mostly in shallow riffleso

Trout - 134 -
Older trout varied in number from 3 to 10 per 100
square yards" Tha es·timate for 'the stream (5'!15'33 yards) was
2,5'00. Most were yearlings (Age I +)o
Salmon
Fry (fish of the year) varied in number from 0.5 to
1 per 100 square yardso Estimate for the stream (5'~5'33 yards)
was 300o Fry were fo·~d only in riffle areaso
Salmon parr made up the bulk of the fish population.
They varied in number from 33 to 44 per 100 square yards. The
estimate for the stream was 14~5'00 (5',5'33 yards). The
majority were age I +o In marked contrast to findings at
Ellerslie Brook and other streams 9 the salmon parr in Cain's
\'Jere found i.n. deep (up to 5· 1/2 feet) poolso In other years
when both bro~k trout ~~d salmon parr were abundant in Cain's,
parr were found only in. flat water areaso
There is the strong possibility thatj) following the
reduction of t1 .. out in the pr;ols, these habitats ware occupied
by salmon parro
Compe~ition
Elans_ru;..isin.g...fi:.Qm c-bs~:~yat;LQns
made o.n Cain v s
Salmon parr will be sparse in 1962o There will be
the opportunity next summer to study the effects of salmon
parr reduction on the nun1bers and distribution of brook trout.
Salmon spawned in the autumn of 1961. If spawning was
successful, there should be a salmon parr population again in
19630 It is hoped by then that trout production will be at a
higher level than it is at present.,
Smolt~
At present we have no knowledge of the movements of
salmon smolts after they have left Prince Edward Island streams
nor do we know that they return to their natal streams. By
marking migrating smolts at Cain's we hope to gain some
information relative to smelt movementso
No .. 63
J. We Saunders
RELATIVE VALUE OF P~INBOW AND BROOK TROUT IN UTILIZING
THE PRODUCTIVE CAPACITIES OF MARITIME FRESH WATERS
Both br·ook and rainbow trout are adaptable to variety
in natural habitats~ ler..d themselves to artificial propagation,
and are px-ized as sport fisho The non. ... indigenous rainbow trout
is established and ·~ontinu.es to spread in areas of the Maritime
province:3 o

Table If._
Comparative yields of brook and rainbow trout to anglers from Crecy Lake
Stocking
Yields to anglers
!2S.
Weight, lb lb/acre
produced in produced in
Bmaber Humber %survival. Weisl'Jt, lb lbfacre lake lake
-
1. Brook trout
Year11 ngs 1, 349 790 S9 355 7.1 88 1.8
Fingerl.iDga 1.4,160 1,6So 12 387
356 7.1
8':9
!22!
Yearlings 1,3SO 1,171 87 S6o 11.2 102 2.0
Fingerl.ings .13,h&o 2,~3 16 311 6.2 291 5.8
1'r.4
7.!'
!22l
Yearlings l,J48 913 68 285 5.1 -b8 -
w
\.1\
tt:t
Fingerlings 13,390 2,83S 21 300 6.0 263
1I:T
19?2
~ Rainbow trout
Yearlings 1,561 1,4l7 91 5S5 ll.l 258 5.2
Fingerlings 13, hbo 83 o.6 31 _0.6 30 o.6
n:T
5.8'
1960
Yearlings 1,350 942 70 215 4.3 74 1.S
Fingerlings 13,42o 2,852 22 356 7.1 263 5.3 HI
II:4 o:tr '"I
0
,;::
cT
~
t-'

Trout - 136 -
Table I ,I • Yield of brook and rainbow trout traa stocking in Simpson' s
Pond P. E. I.
Planted
rainbow
Planted
brook trout
Native
brook trout
trcm stream
Number planted
Sept. 196o
4,000
4,ooo
Number recovered
Sept. 1961
422
168
449
% surv:ival
lO.S
4.2
Mean length
when planted
3.1 in
3.S 1n
Mean length
when recovered
8.4 in
7.9 in
Total weight
when recovered
114.2 1b
32.~ 1b
S6.o lb
Pounds per acre
49.7
14.1
24.3
Weight added in pond
by survivors
108.6 1b
29.4 lb
Poands per acre
42.4
12.8

- 137 - Trout
Viewed either favourably as a species to foster, or
with reserve as possibly supplanting the native brook trout 9
there is as yet little to guide future fish cultural management
of rainbow trout in Maritime fresh waters. Whether the rainbow
trout may be superior to the brook trout in utilizing the ·
productive capacities of Maritime fresh waters~) and in providinc
ancling satisfaction, is under investigation.o
Crecv Lake, New Brunswick
Concurrent stocking, inorganic fertilization and
predator control much improved angling success for brook
trout in soft-water, low-productive Crecy Lake~ New Brunswicko
The procedures were replicated as closely as possible,
substituting rainbow for brook trout in stocking~ Results with
respect to yields of trout to anglers are presented in Table I.
In a detailed discussion, necessarily more lengthy
than here possible, both intra- and inter-specific differences
in catchability, growth and survival to angle:r.s' catches
between the several stockings could be brought outc However,
viewing the results as a whole, no generally consistent
superiority of one species over the other is exhibitedo The
results were obtained without inter-specific competition
between the brook and rainbow trouto
Simpson's Pond, P.E,I.
This 2.3-acre pond, formed on a small brook trout
stream, was stocked with equal numbers of hatchery~reared 9
marked brook and rainbow trouto The fish were planted when
underyearlings in September, 1960? and removed when yearlings
upon draining the pond a year latero Resident stocks of trout
were removed from the pond just prior to planting the
underyearlingso However, during the course of the year, native
brook trout recruits from the tributary stream entered the
pond, largely as yearlingso The pond was screened to prevent
downstream escapement of trouto Data on the standing crop of
trout in the pond in September, 1961~ are given in Table IIo
The introduced rainbow trout underyearlings survived
better and grew faster than the introduced brook trouto This
occurred in the face of competition from an initially equal
number of somewhat larger planted brook trout, as well as a
subsequent recruitment of native brook trouto These initial
results suggest that the rainbow trout~ given equal opportunity
for continued recruitment, could dominate, or even supplant 7
brook trout in pond habitatso
Mo Wo
Smith

SALMON SUMMARIES
catch statistics and Miramichi sampling
traps
Returns of Miramichi salmon tagged as
smelts since 1958
Returns of Miramichi salmon marked as
smelts from 1950 to 1959 by fin-clipping
Natural survival rates of Atlantic
salmon
Increasing salmon fisheries by control
of mergansers
Effects of DD~ spraying operations in New
'Brunswick on young salmon and aquatic
invertebrates
Cruising speed of salmon parr
Measurements of buoyancy in young
salmonids
Number
64
65
66
67
68
69
70
71
Page
139 - 142
142 - 145
145 - 148
148 - 151
151 - 157
158 - 164
165
166

Quebec
R.
e
Ca._pe Go.sfe
~
CvLF A.l'fE/1
IJ. S.R.
'
Sr.llf~>•ffl '-
/ITL/1/VTIC ;/l;f£~

No. 64
- 139 -
CATCH STATISTICS AND MIRAMICHI SAMPLING TRAPS
(a) Sa1mon catch statistics 1949-61
Salmon
. To show the trend of commercial and angling catches
in the Maritime Region over the past 13 years, records of the
Department of Fisheries and the Province of Quebec are plotted
in Figure 1.
. Commercial salmon landings in 1961 in the Maritime
Region (Gulf, Atlantic and Fundy areas) totalled 1,195,700
pounds, a decrease of 7% from the 1960 total of 1 9 283,300
poundso The decrease in total Maritime landings resulted from
a 1961 Gulf total of 903~100 pounds as compared to 1 9 044;100
pounds in 1960o The Gulf area includes the Quebec coast 9 ·
south of Cape Gaspe~ which produced only 185,700 pounds in 1961,
compared to 290,200 pot~ds in 1960o In 1961 the Atlantic area
produced 93,100 pounds, 67% more than in 1960o The Fundy area
gave 199,500 pounds, a 9% increaseo
Angling catches for the Maritime Region (excluding
Quebec rivers) totalled 26,487 fish~ an increase of 13% over
the 1960 catch. Average catch per 10 rod=days remained the
same, at 2ol fish? for the whole Region; an increase for the
Gulf and Atlantic areas was balanced by a decrease in the
Fundy area. The total Maritime catch is influenced heavily by
angling success in the Miramichi river system where availability
of fish has fallen off in recent years as a result of man-made
environmental changes including insecticide spraying and mining
pollution that have been superimposed on natural variations in
water flow, temperature and other conditions.
In Newfoundland, 1961 commercial landings totalled
2 1
043,000 pounds (2.1% below 1960) and anglers caught 17,o48
f~sh in 37 11 074 r.od-days angling, or 7% fewer fish than in 1960.
In Quebec, 1961 commercial catches totalled 537~100 pounds, 9%
lower than in 1960o
(b) Mir ami chi sampliA~ d§ ta
Figure 2 brings up to date by including 1961 totals,
the graph shown in the 1960 Annual Report summarizing available
counts of adult salmon at the estuarial sampling trap and two
counting fences on the Northwest Miramichi tributaryo
Noteworthy is the improved 1961 run of grilse at the
Millbank estaurial sampl~g trap~ as expected from the return to
normal level (about 2 million) of the estimated total Miramichi
smolt run in 1960o
The lower total run of larger salmon at the Millbank
trap and the low number taken during the public fishing season
(similar to 1960) was not unexpected. It agreed with predicted
effects of heavy 1956 and 1957 DDT spraying over much of the

Salmon - 140 -
(/)
q
s
2.0
ol.5
rl.
~
0
~1.0
0
H
.....:!
.....:!
H
~
0.5
0
A. COMMERCIAL
·--~-
---· ...........
~
~ .
" ----­
"· ........ '·-
Atlantic
Maritime
Totaly,~
-~ •
•
/'
/I '•,
/ _/ .......
.
\ ~- /
',.--· __./....... LGulf
---.-­
• .............. _.-•-1-.---•----- Fundy~ --·---·---·---•
·----·-- ~ ·---........ .., _
--·----·----·----·----=--=----==------- -·----·---- ·-- --·
.._..........
60
B. ANGLING
Maritime
Total~
• C. ANGLING
CATCH per
10 rod-days
of effort
50
8
20
( • - Miramichi R.)
10

ltooo
3000
2000
].000
GRILSE
LARGE SALMON
I
NORTHWEST MIRAMICHI (CAMP ADAMS)
COUNTING FENCE .
40 miles above head of tide
6ooo
::r:l
~ 5000
rz.
rz. ltooo
0
0::: 3000
13:'1
~ 2000
;

Salmon - 142 -
Miramichi watershed~ The public commercial nets in the Miramichi
estuary had mediocre fishing in 1961 9 a disappointment to most
fishermen. At the Curventon counting fence there was a poor run
of grilse, not obviously related to the DDT histo~ of this
watershed, essentially free of spraying since 1956~ It could
have resulted from mining pollution effects on smolt survival
in 1960. By contrast? the count of ascending large salmon at
Curventon exceeded the average level of the past few years,
and the run during the angling season (May 15 to September 30)
was the highest since 195~~ the peak year since work started
here. These results were reflected in counts of grilse and
large salmon at the Camp Adams trap~ 33 miles further upstream.
Further details on the relationship of the Northwest Miramichi
data to mining pollution are given in Summary Noo 76o
No. 65
C. Jo Kerswill
RETURNS OF MIRAMICHI SALMON TAGGED
AS SMOLTS SINCE 1958
Information from returns of fish marked or tagged as
smolts adds to knowledge of distribution at sea~ and the general
contributions to the Atlantic Salmon fishery by given river
systems. Other information valuable for salmon management
includes: (1) data on homing; (2) evidence for or against the
hypothesis that early-and late-run salmon are genetically
distinct; (3) data relative to the question of why some salmon
return for the first time after one sea year (grilse) while
others return after two or three years at sea; and (4) numerical
data for estimating the total number of smolts produced by a
river.
Since 1950 many thousands of smolts have been marked
by fin-clipping in the Miramichi and other rivers of the
Atlantic coast. Returns have been useful but often difficult
to interpret because of identification errors mainly related to
fin regenerationo In 1958 the Fisheries Research Board started
a small-scale program using a tag developed by Dro B. Carlin of
Sweden who has had excellent results with itn To date Carlin
tags have been applied to 6,076 smolts of native Miramichi stock
and 5,088 to smolts of Miramichi origin but· which were reared in
Saint John Hatcheryo These fish were released at various points
in the Miramichi system as indicated in Table Io
The data from our smolt tagging program have already
provided useful informationo They are best considered
separately because smolts were tagged at various points in the
Miramichi system and under different conditions.
(a) 1,023 native Miramichi smolts tagged at Millbank, 1958
Of the eight adults which have been recaptured, four
were angled in the Miramichi (two as bright and two as black

TAG RETURNS (TO AUG. 11, 1961) FOR SMOLTS TAGGED DURING 1958, 1959, 196o and 1961 IN THE
MIIUMIOHI RIVER SYSTEM
Total. return %
as adults fran return
·Year Number Method of fisheries and as
tag;d Place tatmed tagged_ CaEture 1958 1959 196o 1961 research tr!Es adults
A.. 19 Milibank 1.9023 .Ang'led.- ••• 1 2 1
COll1llercia1 2 ••• 4 0 0 • 8 o .. 8
Mill bank 6
1958 Camp Adams 25 Curventon 14 ••• ••• ••• • ••
down trap
B. 1959 Mill bank 3,442 Angled • •• • •• 10 4
Commercial. ••• 2 ll 29 59 1.7
Ourventon up
trap • • •
000 5 ...
c. 196o Camp Adams 75o
1-'
Angled 1 +
• • • • •• ••• VJ
Commercial. ... ... 7 6 19 2.5
~nton
dawn .. trap 000 ...
1 •••
Curventon
up trap ... ... ••• 12
Millbank ••• ••• 6 •••
196o Cain 1 s River 132 ••• ••• • •• ••• ••• ••• ooo
D. 1961 Camp Adams 310 Angled . . . . . . ... 1
Commercial ... ... ••• 1
Ourventon
down trap ... •••
000 57
E. 1961 Ourventon 394 Angled •••
• • 0 000 14 ~
Curventon g; ~
down trap .... . . ••• 12 CD
g
Found dead ••• • •• ••• 1 H
Tag found ... ••• ... 1
F. 1961 Wayerton Bridge 5,088 Angled ••• • • • • •• 13
N. W. Miramichi Commercisl. . . . . .. ... 13
and ·Saint John Found dead ... ••• ••• 10
hatchery stock
(I)

Salmon - 144 -
salmon), two were taken in Escuminac drift nets, one by trap
net at Salmon Beach in Gloucester County~ N.Bo,and one was taken
in a trap net near Margaree Harbour, N.So
(b) 3,442 nativ~ Miramichi smolts tagged at Millbank, 1922
To date one post-smolt and 59 adult salmon have been
recaptured. The post-smolt was caught in a herring weir at
Bird Cove, St. Barbe District, Newfoundland. Ten bright grilse,
three black grilse and one bright two-sea-year salmon have been
angled in various parts of the Miramichio Of 11 recaptures in
the commercial fishery after one sea year, nine were caught in
the Miramichi estuary, one in a weir at Harbourville, N.S., and
one near Napassok on West Greenland. Of 29 two-sea-year salmon
taken in the commercial fishery, six were caught in Miramichi
estuarial waters and 17 were caught in drift nets to the northeast,
east and south-east of Miramichi Bay. The other six
recaptures were of especial interest; one was from a trap net
in Bay Ch2leur, one each from St. Philips and White Bay,
Newfoundland, one from Saint John Harbour and two from weirs at
Halls Harbour, N.S" The low rate of return from the 1959
experiment~ as for that of 1958, is possibly owing to the
relatively high water temperature at the time smolts reach the
estuary and the consequent physiological damage they suffer by
being handled at a time when they are very delicaten
(c) 72~ natiye___amolts tagged at Camp A9.ams counting fence in
12 0
From the standpoint of percentage recaptures (2.5%),
this has been the most successful tagging experiment so far.
Only the grilse have entered the fishery yet and 19 recoveries
have already been made. Of these, one was angled in the Sevogle
River which is a tributary of the Northwest Miramichio
Pollution from a base metal mine near the Northwest Miramichi
may have caused this fish to stray from its home river (Summary
No. 76). Five grilse were taken in Miramichi estuarial trap
nets. One fish, length 66.5 em and weight 3 kg, was taken in
October, 1961, by gill net at Napassog Fjord, Greenland. Since
this fish did not return as a grilse, it probably would have
rna tured as a two-, or three-sea-year salmon. Of particular
interest were twelve grilse which went upstream past the
Curventon fence. These were tagged as smolts at the Camp Adams
fence between 25 and 30 May, 1960. The twelve returning grilse
all arrived as early-run fish at the Curventon fence between
June 23 and July 20, 196lo Only one of these twelve was
subsequently seen at the Camp Adams fence 33 miles upriver.
Here again, pollution may have deterred them (see Summary No. 76).
This experiment points out the desirability of tagging
fish of Northwest Miramichi origin. The Curventon and Camp
Adams counting fences allow us to observe many returning fish and

- 145 - Salmon
relate them individually to time and place of taggingo
In 1962 many of the fish tagged in 1960 should enter
the commercial fisheryo This would raise the figure for
percentage returns well above 2o5, the highest attained so far.
(d) and (e) 310 n~tiye smelts tagged at CamP Adams co~ting fence
in 19 1; 394 native gmolts tagged at Curyenton
cgunting fence in 19 1
A number of these smelts were captured in 1961 by
anglers and commercial fishermen in Miramichi waters but none
have been recovered elsewhereo
(f)
A number of both groups (1) and (2} were captured by
anglers and commercial fishermen as they descended the river
and estuary. One of group (1) was captured on September 25,
1961, as a 12-inch post-smolt in a herring net at Fox Harbour,
Labrador.
These salmon of Miramichi origin may provide
interesting biological information~ It will be usefUl to learn
whether they return to the river,in which they spent only a
short time before going to sea. Moreover, we have an
opportunity to learn something about the early-run versus laterun
question since these fish are from late-run parentage; the
eggs were collected from late-run salmon at Red Bank on the
Northwest Miramichi. Finally 9
there may be an opportunity to
study the subsequent growth of the "fast-growing" stock.
No. 66
RETURNS OF MIRAMICHI SALMON MARKED AS SMOLTS
FROM 1950 to 1959 BY FIN-CLIPPING
Ro L. Saunders
Co J. Kerswill
The return of smolts marked on the Miramichi River
is presented in Table I. An adipose-left ventral fin clip was
applied to native fish descending through the Curventon fence
(Northwest Miramichi), while an adipose-right ventral fin clip
was given to native smelts descending through the Dungarvon
fence from 1950 to 1956 and through the Cain's River fence
(Southwest Miramichi) in 1958 and 1959.

Salmon - 146 ~
The number of smolts marked from 1957 to 1959 includes
the numbers of descending spring and fall hatchery plantings
marked adipose-left ventral for fall plantings and adipose-right
ventral for spring plantingso These fish were distinguished
from native stocks by a deformed dorsal fino However~ this
mark did not appear to be always recorded in the recaptures of
marked fish at the fences and thus it would be unwise to analyse
returns of native and hatchery stocks separately for these
years.
Plantings of hatchery stocks in the Miramichi River
account for the large number of returns of adipose-right
ventral fish in the Northwest Miramichi River in the smolt
year-classes from 1957 to 1959o Prior smolt year-classes
(1950-1954) provide a good indication of homing in the Miramichi
Rivero The analysis found in Appendix Noo 75 (Annual Report
1958-59) shows that only Oo4% of the fish returning to the
Northwest Miramichi were strays from the Southwest~ while lo6%
of the fish in the Southwest Miramichi were strays from the
Northwest"
The Dungarvon fence ceased operating in 1956~ thus
recaptures of the 1954 and 1955 smolts at this fence shown in
Table I are in.completeo Similarly~ the Camp Adams fence
commenced operations in 1957 and thus recaptures of smolts
marked in 1955 by this fence are incompleteo The 1959 smolt
recaptures are also incomplete at all traps as these figures
contain only grilse and two-sea-year salmono However 7 as the
numbers of older salmon of this smelt year yet to return are
small, the figures were included in Table I.
Angling and commercial fishery recaptures of marked
salmon provide the highest percentage return on the total number
of fish marked--approximately lo25 to lo50%7 as snown in
Table II. The Dungarvon and Curventon fences, on lower
Miramichi waters provide a return of about 1% of the total fish
marked, while the Camp Adams fence in upper Northwest Miramichi
waters and the Millbank estuarial trap,which samples only a
small proportion of the total Miramichi salmon r~yield 0.25%
or less of the total smolts marked. Total recoveries of all
marked salmon from angling and commercial fisheries and the
Curventon fence are approximately 2o5% of the total number of
smolts markedo
High percentage returns (8-11% of total number of
smolts marked in any one year) of marked fish taken in angling
and commercial catches were found in the smolt years of 1952 and
1957 when total numbers of smolts marked were less than 1,000
(Table I). These high returns were also found when these smolt
year-classes appeared at the Curventon fence. However, high
returns of Dungarvon marks in 1952, as found in commercial and
angling catches, were not duplicated at the Dungarvon fence.
Low numbers of fish marked at the Dungarvon fence in 1950 and
1957 did not yield higher than normal returnso The reason for
the high returns in 1952 and 1957 are~ at present, unexplained.

- 147 - Salmon
FIN-CLIPPED SMOL.-.T....;.S;...._ __..:.::NUMB.:.:.:::~ER~AN:::::.:.:D:::;.....:.P=ER=C=E=NT~A=G=E:-::.::RE=C=A=PTU...::.:.=RE=D---.T_a_b_l_e_I•
Fence.recaptures
Smolt Number
Year Marked
Commercial
Camp
and angling Pungatvon Adams Curyentoq Millb&nk
No. % No. % No. % No. % No. ~
1950 LV 7,969 82 1.03 65 .01
RV 253 3 1.19
1951 LV 3~ ,407 565 1.69 36lf. 1.10
RV 1 ,966 255 1.71 127 .85
1952 LV 8lf.S 11.00 32 3·77 1 .12
RV 461 10.40 1 .22
~~
1953 LV 25,218 199 ·79 267 1. o6 10 .o4
RV 19,966 163 .82 llf-9 -75 1 .005 12 .06
1954 LV 25,660 302 1.18 202 ·79 39 .36
RV 20,254 172 .85 85 .42 2 .01 9 .blt
1955 LV 25,735 375 1.46 7 .03 136 -53 22 .09
RV 13,057 198 1.56 18 .14 1 .005 15 .11
. -
1956 LV 12,733 255 1.95 20 .17 115 .90 20 .16
RV 9,130 154 1.69 1 .01 10 .11
1957 LV 779 66 8.47 18 2.13 If. .51
RV 1,395 24 1.72 3 .22 5 .36 3 .22
1958 LV 19,400 220 1.13 64 ·33 217 1.12 12 .06
RV 12,500 149 1.19 7 .06
1959 LV 20,683 380 1.84 21 .11 194 .94 29 .14
RV 9,250 133 1.44 6 .06 9 .10
TOTAL COMMERCIAL AND ANGLING RECAPTURES 1950-1959 Table II.
TQt~l ma~eg 12. reQin~~gg :!
LV 172, 3 2,537 1. 7
RV 101,232 1,299 1.28
TOTAL FENCE AND ESTUARIAL TRAP RECAPTURES
Place and year Total marked--available
reca:gtur~d ;(or ~eQa:g:kY,~i No 1 ~i c~:giau:eg ~
Dungarvon 1950-1953 RV 35,646 379 1.06
Camp Adams 1956-1959 LV 53,595 112 0.21
Curventon 1950-1959 LV 172,434 1610 0.93
Mill bank 1952-1959 LV 131,056 137 0.10
RV 86,013 59 0.07

Salmon
~ 148 -
Time of marking during the sm.olt run and its effects
on the time of return of marked fish is also open to
speculation~ It has been examined only for smelts marked in
1953, when marking could be started oy May 15 on the Dungarvon
but not until May 24 o:P.. the Northwest because of' log drives.
When the Dungarvon fi.sh returned as adults" 2lo7% of those
returning prior to August l were marked 9 whj.le only 8o5% of
the fish returnin& after this date were markedo On the
Northwest, only 5% of the fish returning prior to August 1
were marked~ while l4ol% of the fish returning after this date
were markedo This suggests that fish descending early as
smelts may return earlier than fish de~s~ending later as smoltso
Further and more precise information on this question can be
expected from tagging data now being a'~cumula ted o
Jo Ho Gee
NATURAL SURVIVAL RATES OF ATLANTIC SALMON
Management of fish stocks which can easily be fished
intensively is faced with the problem of what spawning
escapement i.s nec.essary to maintain the stocks" The answer
hinges on the acc~umulateci rt:Jsults of survival rates from one
stage of the life history to the next? and on the basic
productive capacity of the environment"
Observations on a number of Atlantic streams indicate
that the smelt producing capacity of average rivers is about
l to 2 smelts per 100 square yards of stream bottom under
present natural ·~ondition.so It rises to about 5 smelts per
100 square yards if intensive control of fish-eating birds
is appliedo
Survival rates between various stages of the early
life history have been examined on the Pollett for 8 years of
egg deposition to 6 years of smelt production, and on branches
of the Miramichi for the equivalent of 5 years of egg
deposition to large (pre=smolt) parr without bird control, and
5 years with bird control. The results are summarized in
Table I. It is clear from the values in Table I that
considerable variation pertains to these survival rates in nature.
The Miramichi observations on egg=underyearling rate
were made during a period of relatively high rate for the Pollett.
A good general value would be to combine all observations from
both areas. Bird control is not yet an established management
procedure~ therefore survival values pertaining to its use must
not be used as a guide to what now occurs, but only to suggest
how additional management may in future be used to advantageo
Parr to smelt survival~ without bird control~ is taken as of
the same general o~der as small parr to large parr survival.

- 1'+9 - Salllon
Table I. Obsel"'ftd percentage 8UJ"Viw.l. rates expressed aa mean and its
stamard errOr between several stagea .. at .the .lite hiatOl")' of
Atlantic saJ.mon.: Number. ot ob!arvations f!lntering each •an 1n
brackata. Potential..egg deposition given tar Pollett alone aDd
Pollatt + Miram:ichi streams J anall. parr and large (over 10 om)
parr defined on size rather than age; Pollett, with moetl.y 2-year
smolta, baa neglig1ble •I!Dllall parr" stage. Eggs • potential egg
deposition; fry. umeryea:r'lings; Blllall p •• ...u parr.
Place Egp, to Fry to Small p. to Large p. to Smolts to
trr small p. lEe p. smolta adults
%
Poll.et'J;
~a? !. o.9
M1ram1ch1 5.8 • o.8
(no bird (13)­
control)
Miramichi
(with bird
control)
Se.e Can .. ·Fish. -­
Oult. ·No. 21
1957 p.. 28
%
74.8 + 11.5 37.2 + 3.9
(5) - (5) -
78.2 + 17.8 61.8 + 7.8
(5) - {$) -
76.6 + 4.7 $0.1 + 4.7
(7) - (6) -
7.8 + l.S
(9) -
The survival rates listed above, when combined, will yield 4 to
5' adult i'ish tor each pair ot 10-lb.fl!spawners, an overall
production rate or 2 &1;~, .. ~,
'
•'
As guides to what may be expected under ordinary
variation between cood and poor years, the limits indicated
by standard error oi' the mean values are recommended. FUrther,
inspection oi' original data sugcests that it would be rare to
have more than 2 cood or 2 bad years during the course or a
normal 5'-or 6-year lii'e history span. The observations civen
in Table I. can be converted to a series ot conserTative cuides
for normal survival expectancy as tollowsz
ijOte~tial egg daposition to undfti'earliRfs--6•,
bu this may rise as hich as or fal as
low as~
underyearlingS tO SWill pa~--6~
EU ~~; & ~h~- ~
i but this may rise as hich
as 11 or fal as ow as 5' ••
Slii01ts r a4Uitf-
· Usin& good, average and poor survival rates aa listed
above, eilht lO..lb adult spawn•rs would give rise to -~bout 26,
16 and 6 adults. Under such cond1 tiona about 7($, 5'~ and none
. '

Salmon - 150 ...
Poor
.
Recovery from
Poor
with Average
Survival
......
For
-.... ~ ~.. Fisheries
.........
---~
-....~ ~
~--­ e.c
And ~
~ ~
r, Spawning
....
~
w
n
t
e
r
s
6
II
Smolts
Large
Parr
13
I
160
I
I .
400
I
Small
Parr
1000
1
Under-
' yearlings
!:o!./ .:o:o; :
::;o:..11
Sp:::e:s { ~T¥ I }
............................
..............................
Figure 1. Typical survival values for Atlantic salmon in those Canadian
Maritime streams having commonly a 6-year life cycle from spawning to
2-sea-winter adults. The numbers of adults available for fisheries and
spawning under "Good", "Average" and "Poor" conditions are shown at the
left. The fourth column at the right shows how a river may recover
from the "Poor" situation if conditions for survival return tn "~ .... ., ..... ~-"

- 151 - Salmon
of the adult crop~ respectively, are available as excess pver
required spawning escapement (Figure I). Granted average
survival conditions, even the low yield of adults is capable
of returning stocks to normal in a generation or so. Because
of the mixture of year-classes in each yearns run of salmon,
neither the extremes of good or poor are likely to be observed
often under ordinary conditionso
River stock requirements to fill the rearing capacity
of 1 to 2 smelts per 100 square yards amount to about 10 adult
salmon ( 50 lb of females) per mile length and 10-yard width
of rivera Present rQns frequently approximate and sometimes
exceed this rate in many Maritime riverso Streams with
extensive hydro-electric development are exceptionsa Widespread
DDI' spraying has reduced stocks il'l i:m.pcr.tant New Brunswick
rivers, but recovery can still be rapid if spraying mortality
is sufficiently controlledo
Under present conditions~ fishing for 5o% or less of
the stock appears to be safeo Available data suggests that
less than 30% of adult stocks are taken by commercial and sport
fisheries togethero Thus~ present exploitation &.ppears to offer
no threat to stocks? and may even invo~:.ve some waste. This
situation can? however, change rapidly for the worse if inland
rearing areas are seriously damagedo
No. 68
INCREASING SALMON FISHERIES
BY CONTROL OF HERGANSERS
Po F., Elson
A salmon management study involving control of
fish-eating ducks to increase stocks of young and thereby salmon
harvest from the Margaree River was outlined to the Scientific
Advisory Group on Salmon and Trout, and to the Fisheries Research
Board in 1961 (F.R~B. Biolo Sta9, Sto Andrews,Ann. Rept. 1960-61,
Summary Rept. Noo 75)o Reasons for using the Margaree in
preference to some other stream were set fortho The expectancy,
based on published Board studies~ is that reducing the present
level of merganser predation will greatly increase (2x or more)
salmon stockso To be examined, is whether this will result in
a pro-rata increase in local salmon harvestse
Change in fishing seaso~
Early in 1961 increased restrictions were added to the
salmon fishing regulations pertaining to the areao On
examination of day-by-day commercial catch records for the last
4 years and for 3 years in the late thirties, it was evident that
these new restrictions could lower local catches enough that
demonstration of improvement might be difficulto This situation
was explain.ed to the Province and subsequently, with the wholehearted
concurrence of provincial authorities, action to have
seasons restored to the 1960 level has been initiatedo

Salmon - 152 -
The situation has thus developed towards
implementation in 1962 of this experimental managemento
Consolidation of base line (ioe. pre·-control) harvest and
other biological information, and of methods for identifying
changes in catches have continuedo
Identification of angling improvement
Part of the proposed test involved identification of
improved angling catcheso If catches improved on a pro-rata
basis with stocks, identification of a doubled or greater
catch should be relatively simpleo If catches increased by a
lesser amount, more refined testing would be required. The
mean catch and its standard error for the period 1949-59 was
349 ~ 37 fish per year: under average conditions a mean for
several years affected by control~ greater than 423 plus 2x
the standard error of the new mean should imply improvement.
Using Hayesu method of minimum measurable improvement (F.RoB.
Bull. 99) the following mean catches for the given number of
years would imply improvement.
Years required
Mean catch required
2 3 4 5
616 587 570 559
Another independent test involving comparison of
angling and the associated commercial fisheries was outlined in
1960 (St. Andrews Anno Repto 1959-60~ Noo 75)o
~20
~ B.
16
ti;!
c:r:12
IZl
fl..
!:I: 8
0
~ 4 0
0
•
Septi.
•
....- --,;;:>
• •
•
• •
•
2 4 6 8 10 12 14 16
--
TOTAL FRESHET FLOW IN cfs x 1000
Figure lo Comparison between
average catch per fishable
day and total freshet flow
for July-Au~st (A) and
September (B)for the years
1948-58o Regression
equations representating
dependence of catch. and
freshet flow given in A ·and
B, with associated
probability of this
dependence appearing by
chance alone given in
brackets9

- 153 - Salmon
Freshet discharge and angling ~ccess
Salmon angling success is notorious for being affected
by changes in river discharge levels. Fortunately, discharge of
the Margaree has been recorded in the Canadian Water Resources
Papers since the 1920ws.
Figure 1 illustrates the relationships between total
freshet discharge and Margaree salmon angling success for 1948-58;
it also permits comparison of the effects of freshet flow for two
time periods: July - August, and September. For the analysis,
angling catches have been converted to average catch per
"fishable" day. "Fishable" days are here defined as days when the
flow did not exceed 1000 cfs, a five-times increase over average
daily summer low water flow. "Total freshet flow" refers to the
combined volume of all freshets over 50 cfs~ Angling catches in
June have been omitted from this analysis because these catches
contribute only about 5% to the season's total catch and may be
affected by late spring run-off.
In July and August (Fig. 1A) 1
there is a good
correlation between average catch per f~shable day and total
freshet flow (r = 0.65, p = 0.05). A~out 4o% of the variability
in catch can be accounted for by changes in freshet flows
(r2 = 0.42). An increase in total freshet flow for a season, of
from 5,000 cfs to 10,000 cfs,will tend to give an increase of
about 4o% in catch per fishable day (from regression equation,
Fig. lA). As illustrated in Figure lB, the correlation between
September catch per fishable day and total freshet flow is
negligible (r = 0.18, p = 0.5). Freshet flow in September
contributes little (r2= 0.035) towards accounting for variability
in September angling success.
Understanding these relationships will contribute to
sound ~~alysis of the experimental results.
IdentifiCition of commercial !ishery improvement
Salmon taken commercially in Fishery District 2, the
Margaree area, appear to be of mixed origin. Pata used to
determine the approximate foreign stock contribution to this
fishery is based upon an adult tagging program (1935-37) and a
smolt marking program (1938). It is assumed that the fish tagged
in the commercial catch and released became part of the mixed
stock available to the fishery, and that the area of subsequent
recapture is an indication of their origin.
It is assumed also that the Margaree stocks, moving
south along the coast with non-Margaree stocks, tend to remain
within the influence of the Margaree River waters when they reach
them.
Then:
(a) Marked fish recaptured south of the Margaree R.
influence or in distant areas were non-Margaree
stock.

Salmon
(b)
(c)
(d)
Marked fish recaptured in the Margaree estuary
and river were Margaree sto~k.
Marked fish recaptured in the Margaree R. influence
and northward were of mixed stock origin.
The ratio of Margaree to non-Margaree fish as
found in (a) and (b) can be applied to (c) to give
the proportion of Margaree to non-Margaree stocks
in (c).
Thus the approximate contribution of foreign stocks
to the Margaree catch can be estimated. The recaptures of marked
fish are shown in Table I and indicate that about 55% of the
Margaree commercial catch is of Margaree origin.
The results of the 1938 smolt tagging indicate that
approximately 45% of the Margarae catch was of Margaree origin
in the years 1940-41. Thus about half of the Margaree commercial
catch (Dist. 2) appears to be of Margaree River origin~(Table II).
Recaptures of kelts and smolts marked or tagged in
other Maritime Rivers indicate that distant streams contribute
some fish to the Margaree area commercial fishery. It appears
that these "foreign" fish contribute about half of the Margaree
catch~ (Table III).
Because of the contribution from elsewhere the
commercial fishery cannot be expected to improve in the same
proportion as the angling fishery, but only in proportion to
the Margaree contribution. It i~ hoped to tag Margaree smolts
each spring, of both hatchery and natural stocks. Recoveries
of such fish should assist in identifYing d~fferences in the
Margaree contribution. As a start, about 2,000 hatchery smolts
were tagged in 1961, half with standard Swedish tags and half
with new tags.
Ample stock recruitment
Starting in 1957 annual surveys of young salmon stock
have bean made in the Margaree. Such stocks have consistently
been at high levels. In the last 3 years underyearlings have
been about three times as abundant as required for full smolt
production elsewhere. Angling success on the river has been
below average in the last 5 or 6 years, but underyearling abundance
has been good to excellento The correlation coefficient between
angling in one year and abundance of underyearlings the next, for
angling in the years 1956-60 and underyearlings in 1957-61, could
well appear b,y chance alone (r = 0.395; .5

- 155 - Salmon
Table I. Source of Margaree (Dist. 2) catch as indicated by
area of tagged fish recaptures 1935-1937· Total
number tagged - 528; total number recaptured - 150.
Percentage of total
number of tagged
!;i.sh recaptured
Angling - Margaree River
Estuarial hatchery traps -
Margaree Harbour
Commercial catch outside District 2
Commercial catch - District 2 south
of influence of Margaree R. --= ___2
Total % of assumed stock origin ~ ~
Mixed commercial catch in District 2
north of influence of Margaree R. (lOo% 3o% - 25%) = 45%
Stock origin estimated from above ratio
of total assumed stocks - 30/55 x 45 25
- 25/55 X 45
Total
19
11
18
Table II. The 1938 Margaree smolt marking results.
Number of smolts marked - 31,332; estimated
smolt production - 133,000
Catch year - Districts 2 and 3
l9!t.Q
Recoveries of 1938 marked smolts
Estimated number of 1938 smolts caught
Total commercial catch
% contribution of 1938 smolts to catch
2,~~
9,000
27%
J..m
41b
1,740
9,500
18%
Total contribution of Margaree R. to Dist. 2 catch - ~

Salmon - 156 -
Table III. Recoveries in District 2 of salmon smolts and
kelts marked in gistant rivers
Number Marked Recovered in
Smolts marked in years District 2
Origin
Pollett 135,132 1950-58 26
N. W. Miramichi 150,319 1950-58 2
Miramichi 4,490 1958-59. 1
Dungarvon & Cains 87,220 1950-58 0
Little Codroy 56,399 1954-58 1
Port Daniel 10,928 1953-58 1
River Phillip 35,000 app. 1955-58 3
Maine Rivers thousands 194-8 to date 2
Kelts
Morell 780 1923-30 1
Sackville 637 1935-37 2
River Phillip 2,472 1940-4-8 2
Other 14,609 1913-52 0
(Margaree 3,867 1913-40 123)

- 157 - Salmon
The Canadian Wildlife Service has conducted methodical
studies of merganser incidence on the Ma~garee for the past 5
years$ These, coupled with earlier Margaree studies by FRB, show
a fairly constant rate of incidence of 10 to 12 birds for such a
unit of territory betwe~n April and November each year.
The Service's recent studies have confirmed the
presence of some birds on open water reaches even through the
winter months. Banding studies have indicated that in autumn
and winter some of the Margaree-reared birds tend to move to
coastal waters off western Cape Breton and Prince Edward Island.
Some Miramichi birds occur as migrants in late autumn off eastern
New Brunswick coasts. Mixing in these areas has not been
observed. Some of both groups do~ however~ move southward along
the Nova Scotia Atlantic coast and at least as far as southern
New Englando A Margaree bird was o·bserved during mating season
on the St. Mary's River, Nova Scotia. This suggests that even
if control should result in complete extirpation of local stocks,
which is unlikely, new populations would recruit from elsewhere
if for any reason it was desired to terminate controla
Resumi
A background of facts pertaining to Margaree salmon ·
fishing has been established. Predation on young by mergansers
is seen as the limiting factor for stocksft That fishing success
bears some relation to stock abundance has frequently been
advanced in the past. Recent evidence from heavily sprayed New
Brunswick streams shows that young stock abundance, at the
smolt stage or earlier, does have a general effect on subsequent
angling success (Summary No. 69(~1Whether management of salmon by
control of mergansers can be made a practical procedure can only
be determined by a study such as that proposed for the Margaree.
If it cannot~ there is little to be gained by any other form of
management designed to increase stocks of young at pre-smolt
stages which may still be subject to heavy predation by
mergansers.
Po F. Elson and J. H. Gee

Sa~~on - 158 -
No.··;:,g9
· r
EFFECTS OF DDT SPRAYING-OPERATIONS IN NEW BRUNSWICK ON
YOUNG SALMON AND AQUATIC INVERTEBRATES
This is a brief outline of the projects undert~en
recently by the Fisheries Research Board and Department ot
Fisheries to determine the effects on salmonid fishes and their
food, of the 1961 and earlier DDT spraying operations in New
BrQ.nswick. It is based on a summary report prepared for The
InteX"departmental Committee on Forest Spraying Operations, Ottawa,
November 22, 1961, with some additions of results of later
analyses.
Previous to 1960 "fUll-strength" spraying in New .
Brunswick was the application by paired planes of 1/2 lb of DDT
dissolved in 1/2 gal of oil, per acre of woodlandn Small-scale
tests in 195'8 and 195'9 with ''half-strength" spraying
(1/4 lb DDT/1/2 gal/acre) showed less severe effects on fish
and their food. In 1960· and 1961 "half-strength'' spraying was
incorporated in the regular operational budworm control programme
of Forest Protection Limited. ·
(a) Short~term mortality tests with caged young sa1mon
and trout, 1961. Hatchery-reared salmon parr, trout fingerlings
and trout fry were held in cages in lower sections of four streams
within the 1961 operational spray area in the Nashwaak and
Miramichi drainages. Two of the streams received single halfstrength
(1/4 lb DDT/1/2 gal/acre) application~ two received
double application of the same spray with an interval of about
10 days. Similar lots were held near the lower end of the Molus
River which received a single half-strength application for a
special experiment with aquatic invertebrates~ and in the upper
Northwest Miramichi at Camp 4dams, the unsprayed control.. No
streams suitable for fish holding tests were sprayed at fullstrength
(1/2 lb DDT/1/2 gal/acre) ..
Results: Mortalities of salmon parr 1n single halfstrength
sprayed watersheds were of similar order to those
receiving half-strength application in 1960~ indicating less
sev~re effects than with full-strength application regularly.used
previously.. Double application at half~o.strength appeared to have
as severe effect on salmon parr survival as single full-strength
used previously. Data for trout were inconclusive.
Ho Eo Edwards (Dept. of Fisheries)
and c. J. Kerswill
(b) Relatiye effects on native young sa1mon populations
of single full-strength, single half-strength and double halfstrength
applications of DDT insecticide. In 1961, autumn
electroseining assessments ot young salmon populations were
continued at representative stations on tributaries of several
river systems including the Miramichi and Nashwaak, having
different spray histories.. In addition assessments were made on
the Molus, sprayed once at half.strength in 1961, and on adjacent

= 159 - Salmon
unsprayed streams in Kent Countyo Data similarly obtained in
1960 on the unsprayed Margaree, N. So 7 were used in this analysis
of data obtained over several yearso Condition factors have· been
calculated indicatini "fatness" of specimens taken during autumn
electroseining to show possible effects of altered diets related
to changes in invertebrate fauna~
~§sults: Data comparing sinile applications of halfstrength
and full~strength DDT spray are swmmarized in Table I.(Pg.l64)
With single half-strength spraying, native populations of
underyearling and yearling salmon are reduced to about half the
normal populations for unsprayed streamsG Older young salmon
are less affected so that 3 months after spraying they represent
about f of the number needed for full smolt productiono These
effects of half-strength spraying have been much less serious
than effects of earlier fUll-strength sprayings where
underyearlings were practically eliminated. Young salmon in
both half-strength an.d full-strength sprayed streams averaged
shorter and thinner than those in unsprayed streams.
Two half-strength applications at an interval of about
10 days appear to have had somewhat less serious effects on
native young salmon than a single full-strength application, but
are much more harmfUl than a single half-strength application
for all year~classes, especially for underyearlingso Such
double spraying may leave only 5% of the number of fry needed
for-full smolt production.
It seems possible that a single half-strength
application of DDT insecticide, if not repeated during the 3
following years, would have scarcely noticeable effects on adult
salmon catches resulting from the young salmon in the affected
streams.
P. Fo Elson
(c) iffect~ h~lf-strength sprgying on ~guatic
invertebrates, Molus Riyer, 1961. On June 11~12, 19 1, the
whole 10-mile long Molus watershed, Kent County, was sprayed
experimentally at half-strength (1/4 lb/1/2 gal/acre) to permit
investigation of the effects on invertebrate fauna at several
stations from source to mouth, in relation to distribution of
insecticide as shown by water analyseso Seven stations were
used, including three which were covered intensively--one well
up the northwest branch, one just below the confluence of the
two main branches and about halfway down the watershed, one just
above head of tide.
Three sampling techniques were used: (a) Pre- and
post-spray Surber square-foot bottom sampling; (b) Collection
of aquatic insects emerging from yard-square areas into cagetraps,
from 2 to 3 days before until 10 days after spraying,
with cages cleared hourly except during final week; (c)
Collection of downstream drifting insects and debris on 12 inch
x 12 inch 25-mesh coppar screens? cleared hourly from several

Salmon - 160 -
hours before spraying until 48 hours after spraying~ and then at
increasingly longer intervals to 24-hourly by June 2lo
Time~consuming analyses of water samples by Department
of Forestry and working over of many samples tor aquatic
organisms have not yet been completed.
Results: At this stage of analysis it appears that:
(a) From Surber sampling, half~strength spraying has less
drastic effects than full-strength spraying used previously;
yet reductions between pre- and P.ost-spray aquatic invertebrate
populations ranged from 72 to ~3%e (b) Adult emergence cages
were of little use during this short, cold~ early-season period
when few mayflies and stoneflies were emerging. They did
indicate that pupal stages of many Chironomidae were little
affectedo (c) The drift screens gave samples that should provide
much valuable new information when fully analyzedo There is
evidence of different degrees of suscepttbility among the various
groups of insects~ based on the time and duration of their
appearance on the screens in relation to the time of spraring.
Among those showing high susceptibility to poisoning are
blackfly larvae 7 nymphs of ~tacenia~ ~ and Para1eptopblebia,
mayflies and larvae of hydropsychid caddisflieso More resistant
forms are nymphs of ~~merella and Stenonema carolina mayflies
and those of Leuctra stoneflies.
F. Po Ide
(d) Recoyery of aquatic insects in branches of Northwest
Miramichi Riyer haying dlfferent spray histQries. In 1961 as
previously~ emerging insects were sampled from May through Au~st
by 2~hour, 5 times-per-week collections in series of yard-square
cage-traps at (a) Camp ~2~ in area sprayed in 1954;(b) Camp Adams,
in area sprayed in 195~ and 1956; (c) Trout Brook, in area sprayed
in 1956. Daily collections have been analyzed qualitatively and
quantitativelyo
esult~~ Immediately after aerial DDT spraying the
aquatic insect fauna in affected streams typically declines
sharply and little emergence occurs for several weeks. Later in
the summer of spraying, the total number of emerging insects per
unit area of bottom rises above normal levels but the total
volume per unit area is much below normal; there are fewer kinds
then, particularly of larger~sized forms like caddisflies, but
more individuals of smaller-sized forms like midgeso The
larger-sized insects," which are the preferred food of salmon parr,
have been slow to return. After several years with no further
spraying, however, the trend has been for total number per unit
area to decrease and total volume per unit area to increase, as
the species composition returns to normal. Extreme flooding in
May 1961 disturbed the bottom in many places, which may have
contributed to a relatively low production of insects at all
stations in this seasono
Fo P. Ide

- 161 - Salmon
(e) Delayed, ¢old weath~r mortality in DDT sprayed
;tream,§ .. · In late autumn, as water temperatures approached
freezing, dead and moribund young salmon have frequently
been seen in streams wh:tch received full-strength DDT earlier
that year. Such mortalities have not been noted in unsprayed
streams. In 1960 and 1961, in late autumn, young salmon newlr
collected from sprayed and unsprayed streams were subjected to
varying decrees of chilling at St. Andrews.
Results: Chilling from 11° C to 5° C or from lower
temperatures to within a degree or two of freezing were
accompanied by death within a few days of about 90% of the
fish which had received full-strength spray. Fish which had
received 2 doses, about 10 days apart, of half-strength spray
as;well as full-strength the previous year, all died with
chilling. Those ~·eceiving .two half-strength doses in addition
to a single half-strength dose the preceding year, also all
died.. Of those receiving as ingle he.lf-strength dose in
addition to a t-strength dose the previous year, 4o% died
within a week. None of those receiving a single half-strength
dose died~ even though they may have surv·ived a full-strength
dose the preceding year.
As temperatures rose from 1° C to 3° C as might
happen in rivers in the spring, there was some indication of
mortality to fish which had received heavy doses. Some spring
observations of dead parr in rivers sprayed the year before
have been made.
P. F. Elson
(f) Recent Miramichi adult sa1mon rwns in relation
to forecasted effects 0 t DDT sprayin&s. In 1957 on the basis
of reduced populations or young salmon in recently sprayed
Miramichi streams, particularly in the extensive Southwest
Miramichi drainage sprayed in both 1956 and 1957, it was
predicted that adult salmon returning to the Miramichi would be
noticeably scarce in 1960 and 1961. Catches by estuarial trapnetters
and Southwest Miramichi anglers have been low, as
predicted (See (g) below). A good index of abundance is
provided, by the F.R.B. estuarial sampling trap operated·near
Chatham through the whole open water season. From spring to
October 31~ 1961, the trap took 6,844 grilse (53% increase over
1960) but only 2,988 large salmon (35% decrease from 1960).
The larce salmon were mostly 2-sea-year fish from the 1959
smelt run, but some 15- to 20-pounders were taken, ige~tif~ed
by scale-reading to be from the 1958 smelt run. The 1961
increase in grilse (1-sea-year adults) was expected because the
estimated total Miramichi smelt rw1 in 1960 was back to normal
at around 2 million, as compared to under 1 million in 1959.
c. J. Kerswill

Salmen - 162 ~
(g) ~ffect of forest spra~ing on §almon anglingo In
late 1957 an attempt was made to estimate the probable effects
of DDT spraying on stocks of adu~t salmon available to a number
of New Brunswick rivers up to 19blo These estimates were based
on the proportions of drainage basins sprayed and the prqportionate
mortalities of young stock attributable to spraying as previously
observed in the Miramichi rivero These estimates attempted to
forecast stock trends not as absolute values but rather lilLJi
percentag~ of xhat tnev woyld have been with no sprayingo The
estimates had to be so stated owing to lack of knowledge about
absolute stock values. To subject such estimates to a comparison
with corresponding actual adult stock values would be a rigorous
test of their validityo Nevertheless, such a comparison has been
madeo
Aside from angling catches 9 there are little data to
indicate actual adult stocko The comparison of estimates to
catches therefore involves two assumptions,first, that angling
catches are, on the average, some reflection of stock size;
second, that stock size was sufficiently affected by spraying to
show through other variable factors~ such as water flow and
weather which affect anglingo
Since it canr1ot be known what stocks would have been
without spraying~ the 1949-54 average angling catches have. been
used as a base against which to measure subsequent variationso
These are the immediately preceding years for which spraying
could have no effect, or only a negligible oneo
To minimize effects of other factors, the course of
angling success in some important ·unsprayed streams of Nova
Scotia has been plotted for the years under consideration
(Figure 1 A)n Conditions for successful angling attract more
angling, and the reverseo Therefore, angling success has been
measured in terms of catch per rod day~ as being less subject
to external causes of variation than total catcheso
It is assumed that the trend for these unsprayed
streams indicates some general factors affecting salmon catches
and the stocks from which the catches are drawno The
predictions made in 1957 have been adjusted to conform to this
trendo
Comparison of the adjusted estimates and observed
catches for several sprayed streams can be seen in Figure 1, B
to F. Among the 7 streams tested, the poorest correlation
between estimate and catch was observed for the Northwest
Miramichi river (Figure 1 B), the best for the Kedgwick river
(Figure 1 E)o For individual streams or systems the correlation
coefficients for estimate and catch are about Oo5, suggesting
that about 1/lt of the variability in catch is directly related
to the effects of sprayingo The probabilities of such
relationships appearing purely by chance lie between 1 in 5 and
1 in 20. But the probability of~ these relationships
appearing simul tan.eously by chance is less than 1 in lOOOo

50
25
100
75
50
25
0
50
- 163 -
"'" I .\/.
." c •
.--- .
A
•
c
I
•
,_ I .
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. ~ ....
Salmon
_;::.,..._ -- ..... --. ... ,_
-·- --·
D
B
'd 75
~
Q) 50
C)
fJ
'd
,- ~,,/·-·
1
.,
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R 25 i- ·- "
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~100
0
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'd
$ 50
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fl)
l!il
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,~
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E
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I I I 1 f- I
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·---.
'55 •56 '57 '58 '59 •6o •61 '55 '56 '57 1 58 '59 •6o •61
Figure 1. Relations between angling catches per rod-day (---) and
estimates of stock abundance (---) as affected b,y DDT
spraying; DDT effect adjusted to conform to r.ecent angling
success pattern for unsprayed rivers in Nove1 Scotia. All
values plott~d relative to 1949-54 average for each~stream
= 100. A--angling catch for Nova Scotia rivers; B-­
Northwest Miramichi; C~~Restigouche
system; E--Kedgwick; F--Tobique.
system; D--Miramichi

Salmon - 164 -
Some of the largest discrepancies between estimated
stock size and angling catch are explainable b.r known_factors.
For example the year 1955 produced a hatch of underyearlings
about twice as large as average. This was observed in northern
and southern New Brunswick and Prince Edward Island; it applied
to the Margaree in Cape Breton. In the Northwest Miramichi,
many of these_l955fish grew to smolt size faster than averace
and contributed to angling bT 1958 (Figure 1 B). A similar
factor may have operated in parts of the Restigouche system
(Figure 1 C). On the Tobique river, angling in 195~ was
adversely affected by construction of the Beechwood dam about
20 miles below the mouth of the river; from 1959 to 1961 it
was augmented b.r early swmmer mechanical transportation of
adult stock from Beechwood to the Tobiqueo
Two broad conclusions are indicated: (1) Angling
success does, in a general way, though not necessarily for
specific years, depend on the abundance of young converted to
adult stock; (2) Extensive pollution by poisonous insecticides
has affected such stock sizes sufficiently to affect anglinc
success.
Po F. Elson
Table I. Populations of young salmon in unsprayed streams and
streams sprayed with DDT, given as average numbers
per 100 sq yd, together with mean lengths (em),
weights (g) and condition factor (K = ~) for
underyearlings, small parr (10 em total length and
under) and large parr (over 10 em) .. Unspraved streams:
West St. Nicholas and Coal Branch, Richibucto system
in 1961; N. W. Miramichi above Tomogonops in 1953
and 1960; Margaree in 1960. Hgrf-strengtb sprayed:
Malus, Richibucto system in 19 1; Cains and S. W.
Miramichi, Miramichi system, in 1960o Fu11-strengtQ
sprayed: Nashwaak in 1960.
Control Half-strength sprayed Full-strength sprayed
HQ s~~~ lt~ l~ QDTLlL~ calLag~g lL~ l~ DMLlL2 ~:S&J.Lg.g;r=l
Underzearlin&S
No./100 yd 2 25.3 1~.9 0.1
Length 5.0 ·9
• 0 0
Weight 1.4 1.2 • • 0
K 1.075 1.003 0. 0
Small Earr
No./100 yd2 31.3 16.8 10.9
Length 8.5 8.~ 9.2
Weight 6.6 5. 7.6
K 1.049 0.963 Oo965
Large parr
No./100 yd2 13.2 8.4 9.0
Length 11.1 11.1 11.1
Weight 14.7 14.3 13.1
K 1.053 0.963 0.944

90
- 165 -
Salmon
80
• •
~
70
..-1
~ 6o
......,
4-t
I 50
~
rxl
~
0..
til
0
!24
H
4o
30
til
20 H
~
0
10
• •
• •
~·.
0
0 1
2 3 4 5 6 7 8 9
WEIGHT OF FISH - gm
Figure 1. Cruising speed of salmon parr at 16° C.
No. 70
CRUISING SPEED OF SALMON PARR
10 11 12
The cruising speed (maximum rate of swimming which
could be maintained for an hour) of salmon parr was measured
in a rotating circular trough. Parr weighing from 2 to 11
grams were acclimated and tested at temperatures near 16° c.
The sample studied included yearlings and two-year-old parr.
Cruising spe_eds were between 40 and 84 feet per minute.
These increased with size of fish and apparently also with
"fatness" or condition. The relation between size of parr
and the cruising speed is shown in Figure 1. These results
will be used as a background for investigations of possible
weakening effects of such stream pollutants as DDT and copper
and zinc.
R. L. Saunders
J. B. Spracue

Salmen
No. 71
- 166 -
:MEASUREMENTS OF BUOYANCY
IN YOUNG SALMONIDS
Mro H. Co White (Atlantic Biological Station Annual
Report, 1934) reported that the swimbladders of salmon parr
from quiet waters are more distended than those in parr from
rapidly flowing watero This suggests that the former are
more buoyant than the lattero A state of neutral buoyancy is
an advantage to a fish swimming at mid depth in quiet water;
lack of buoyancy undoubtedly helps a fish maintain its position
on the bottom of a rapidly flowing streamo Such degrees of
buoyancy would help the fish maintain their positions in their
respective habitats with the minimum expenditure of energyo
The ability to regulate buoyancy may be an important factor
affecting the survival of salmon and trout in nature where
they may move from quiet to flowing water or yice yers&o Such
an ability would also be an advantage to hatchery fish when
moved from relatively 3low to fast water or the reverseo
Because of the possibly important aspects of buoyancy regulation
by salmon an.d trout, an attempt was made to learn more about
this interesting adaptationo
Fish were anesthetized in large carboys partly filled
with water. A partial vacuum was applied to the carboy and the
minimum reduction in pressure necessary to cause the fish to
rise from the bottom was taken as a measure of the buoyancyo A
greater degree of "\racuum. requlred indicates low buoyancy and
.D.£§. yersao
In preliminary experiments made in the field it was
established that there are measurable differences in buoyancy
of salmon and trout between groups from rapids as contrasted
with those from still wate~u Those from slowly flowing water
were more buoyant than those from rapidly flowing watero Under
identical conditions trout were more buoyant than salmono
In better controlled laboratory studies salmon adjusted
rapidly to changing water velocities; increased velocities were
followed by decreased buoyancies in less than 24 hours and the
reverse. There were indications that some individuals adjusted
more quickly than others to changes in water velocityo These
appeared to be the more robust fisho An interesting observation
concerning the fish in a large holding tank was that healthy ·
ones regardless of length generally stayed near the bottom of
the tank and appeared to be negatively buoyant; those swimming
near the surface were buoyant but very thino The latter usually
diedo
Experiments planned include measurements of the specific
differences between salmon and trout in the rate and magnitude of
buoyancy regulationo A study will be made of the abilities of
buoyancy regulation among salmon ranging in size from fry to
smelts.
Ro Lo Saunders

INSHORE COD PROJECT SUMMARIES
Oxygen conswaptio-n or cod
Survival of live cod in a storage box
Number
72
73
Page
167 - ~.69
169 - 170

No. 72
- 167 - Inshore cod project
OXYGEN CONSUMPTION OF COD
The purpose of this study is to provide information
concerning the oxygen requirements of cod held in impoundments
under various conditions of temperature and crowding and with
different degrees of starvation and satiety •. Most of these
measurements were made using a mass respirometer holding
different numbers of cod. The rate of oxygen consumption was
measured daily as the cod approached a starvation level. After
5 to 7 days following feeding, the rate of oxygen consumption
became reasonably constant; this level was taken as the routine
rate. After the fish were fed to satiety the rate increased to
a maximum within the following 24 hours. The metabolic rate
then subsided and often levelled off at the previously established
rate in an additional 5 to 7 days. Most experiments were carried
through only one cycle of starvation and satiety.
An attempt was made to elicit an increased level of
activity and thus a metabolic rate approaching the active one
(rate elicited by the maximum sustained swimming speed) by
revolving a paddle near the bottom of the mass respirometer to
prevent the cod from resting there. However, this resulted in
no increase in the metabolic rate because cod do not usually
rest on the bottom of the respirometer but swim about slowly at
mid depth.
A more precise respirometer was used to measure the
rate of oxygen consumption of single fish. This is a large
plexiglass tube which holds a fish so that it can breathe without
restraint but which does not allow sufficient room for the fish
to swim.
It must be emphasized that neither of the respirometers
used permits a measure of the active rate of oxygen consumption.
However, the data obtained may be used to predict the oxygen
requirements of satiated or starved cod under routine conditions.
Actively swimming cod would undoubtedly require more oxygen.
The main results are summarized in Figure 1. The
effect of feeding is to raise the routine rate of oxygen
consumption above the starvation level by between 25 and 35%,
depending on the size or the fish. A size effect is demonstrated;
small individuals consume oxygen at a greater rate per unit
weight than do large ones. Except for ~ery small fish, there is
little difference in the metabolic rate between temperatures of
10 .and l5°C. With the smaller fish (0.15 ~ 0.5 kg) used in the
experiments at l5°C, there was a sharp rise in the metabolic
rate with decreasing size. Rates obtained using the single fish
respirometer are mostly slightly lower than the minimum ones
with the mass respirometer. This is to be exepcted since it was
observed that fish in the mass respirometer swam continually

1-4
..c:
..........
bD
~
..........
bD
s
240
220
~
~
••
A satiated fish' Figure 1.
~mass
• starved fish )respirometer
e starved fish - single
fish respirometer
Effects of feeding on the routine
levels of oxygen consumption of
various sized cod acclimated at
temperatures of 10 and l5°C.
The lines have been fitted by
inspection to points determined
in experiments using the mass
respirometer. Datum points from
experiments with the single fish
respirometer are shown for
comparison.
Conversion factor for weight:
1 kg = 2.2 lbs
H
::s
{I)
p-
0
11
(I)
n
0
p.
't:S
11
0
~
(I)
n
cT
s:::
0
..-f
+'
~
{f)
s:::
0
()
s:::
Q)
bD
~
0
~
0
•
. ·-------.
• •
0 0............... 0
•o~·-·~.
o I
15°C
......
0\
CD
Q)
+'
ct:l
~
• ..
•
-· •
0
A
0
l0°C
---·
40~------L-------~------~------~-------L------~~----~------~
0 1 2 3 4 5 6 7 8
Weight of fish - kg
-·

- 169 - Inshore cod project
while those in the other apparatus were unable to swim.
different levels of activity are, then, reflected in the
different metabolic rates.
Under the conditions of the experiment a greater number
of fish in the mass respirometer consumed oxygen at a slightly
lower rate than did a reduced number of the same size in that
apparatus. It is suggested that with few individuals in the
chamber there is more room for them to swim around and consequently
a higher level of activity and metabolism than under crowded
conditions.
A third series of observations is being conducted at a
temperature of 3°C. This should provide particularly useful data
since cod are most often caught in water at or near this
temperature. · These experiments are scheduled for completion on
March 31, 1962.
No. 73
SURVIVAL OF LIVE COD IN A STORAGE BOX
The
R. L. Saunders
Beginning in June 1961, a test was conducted at Burin,
Nfld., to determine whether or not commercial quantities of live
cod could be stored in large crates floating in the sea. An
estimated 14,000 pounds of live cod (about 2,500 fish) were
transferred from a cod trap to a towing net, towed for 5t hours
(2 miles) and then transferred to a wooden storage box measuring
18 feet x 10 feet x 6 feet. Eleven fish died during the towing
period and 31 fish died within the first 24 hours in the box.
These deaths were directly related to handling and amounted to
0.6% of the total number of cod.
Environmental conditions in the box at 24 hours were
suitable. Surface temperature was low (44.6°F), surface salinity
was normal (31. 7%•) and under these conditions dissolved oxygen
in the water throughout the box was normal.
Observations of mortality and temperature were continued
over a 39-day period by personnel of the nearby fish plant.
Water temperature ranged from 42°F to 53°F and averaged 48.1°F.
Deaths were as follows:
Storage time
in days
1 - 7
8 - 14
15 - 21
22 - 28
29 34
35 - 39
Deaths
23
92
83
11
3
___!
Total 213 (total wt. 1,210 lb)

Inshore cod project - 170 -
The loss over 39 days was about 10% on the basis of
numbers or weight of fish. Most of the deaths (211) occurred
within the first 24 days. The parasite, Lerneocera branchialis,
was present on 9.8% of the dead fish. Since 18 to 20% of cod are
likely to be host to this parasite, it does not seem likely that
the parasite is responsible for the deaths.
A tentative conclusion from these few observations is
that it is possible to store commercial quantities of live cod
for periods up to 40 days if losses of 10% can be tolerated.
D. W. McLeese

POLLUTION SUMMARIES
Pollution studies
Pollution~control
effectiveness
efforts by a mine, and
Effects of mining pollution on the movements
of adult salmon in the Northwest
Miramichi River in 1961
A new method of estimat~ng the degree of
mining pollution which disturbs salmon
migrat.ion
Heavy metal pollution. Lethal and sublethal
effects on young salmon
Heavy metal pollution. Effect on fish
:t'ood organisms
Relation between base aetals mine
effluent and production of young salmon
Surveys of possible pollution in estuaries
Number Page
74 171
75 171 - 172
76 172 - 174
77 175 - 177
78 177 - 179
79 179 - 180
80 180 - 182
81 182 - 183

5 MILtS
~"' ~~.-f.
~
Figure lo Simplified map of area studied for heavy metal pollution.
Labels indicate work carried out at various locations~
"cage" = fish held in cages;
"fish" = population estimates of resident fish;
"invert" = sampling of aquatic invertebrateso

No. 74
- 171 -
POLLUTION STUDIES
Pollution studies
In the Maritime Provinces, one of the big problems
facing freshwater and inshore fisheries is water pollution.
D.D.T. and othet agricultural poisons, mining pollution, food
packing wastes, pulp mill effluents and contamination by sewage
are some of the immediate dangers. One weakness in combating
these threats is a lack of basic scientific facts on how pollution
affects fish. The pollution studies group at St. Andrews is very
small, but is attempting to provide basic knowledge about some
problems. It is hoped that other. agencies will make use of these
facts as a basis for sensible measures of conservation and control
of pollution.
In 1961 most research effort was on the effects of heavy
metal pollution. This was done by field work on the Northwest
Miramichi River, polluted by mining activities on a tributary,
the Tomogonops River. Work was completely integrated with that
of the Salmon Investigation at St. Andrews and the Department of
Fisheries, as indicated in the summaries which follow and cut
across the boundaries of these groups.
Underlying all biological conclusions in these summaries
is a foundation of numerous and precise chemical analyses. About
one thousand water samples were processed during the year, and the
determination of zinc and copper required great care and perseverance.
This chemical work by W.V. Carson is gratefully acknowledged.
No. 75
POLLUTION-CONTROL EFFORTS BY A MINE,
AND EFFECTIVENESS
J.B. Sprague
In 1960, pollution of the Northwest Miramichi River by
zinc and copper caused trouble with salmon migrations and with
resident populations of small fish. Pumping operations to empty
a mineshaft of water contributed a large percentage of the
pollution. Pumping ceased in July of 1960, but there was still
considerable contamination of a stream from piles of mill tailings.
In August 1960, the mine started treating the stream by adding
lime and collecting most of the zinc as precipitate in a settling
pond. This system proved to be inadequate during heavy freshets
in the autumn of 19oO. At the peak of one freshet, zinc actually
reached a lethal concentration of 1.0 mg/1 after mixing
thoroughly into the Northwest Miramichi River.
In late autumn of 1960, a larger and more complex system
of settling ponds was constructed. Fairly good control of
pollution was achieved during the winter and spring of 1961, with

Pollution studies - 172 -
a maximum of Ool4 mg/1 of zinc detected in the Northwest Miramichi.
This was considerably less than 0.25 mg/1 found the previous June,
but was still double the tentative "safe" level, estimated last
year as 0.06 mg/1. Unfortunately, as described in Summary Noo 77,
soft river-water during the spring and proportionately more copper
caused pollution to be more dangerous to fish than was indicated
by this tentative "safe" limit based on zinc alone.
Control of pollution was good throughout the summer;
zinc approached natural background levels. However, it rose
above the "safe" level for much of October, reaching Oe22 mg/1
during one of the freshets. As shown in Figure 2, zinc varied for
the remainder of the year, but tended to oscillate about 0.06 mg/1.
In the latter part of December, there was a gradual rise
in pollution. Part of the additional load of metals may have come
from the main tailings disposal area, which had previously been
an insignificant contributor. In early December 7 the South
Tomogonops River which drains this area, showed an alarming rise
in zinc content, from 0.8 mg/1 to 6.5 mg/1, during a period of only
10 days. On the basis of dilution ratios, the South Tomogonops
alone could have raised zinc concentrations in the Miramichi above
the preliminary "safe" estimate, if all zinc stayed dissolved in
the water.
Compared to the previous year, pollution was considerably
reduced in 19ol, especially with regard to upsurges during freshets.
However, metal concentrations were high enough to disturb salmon
migrations, as described in the next summary, and potential for
pollution may increase in the next year when milling of ore starts
again. It is obvious that agencies responsible for controlling
pollution should keep a continuing check on conditionso In 1962,
water sampling by Fisheries Research Board for research purposes
will provide a monitor only of total pollution reaching the
Miramichi. Searching appraisals by personnel of the mine, or
other competent groups will be desirable to ensure that significant
sources of pollution are not neglected. For example, sampling in
1961 by a Department of Fisheries engineer showed good control of
the main source of pollution. However, it also showed that a
seemingly insignificant creek doubled the total load of zinc
leaving the mine areao
No. 76
J.B. Sprague
EFFECTS OF MINING POLLUTION ON THE MOVEMENTS OF ADULT SALMON
IN THE NORTHWEST MIRAMICHI RIVER IN 1961
During the spawning migration of 1960, it was observed
that unusually large numbers of adult salmon were moving downstream

- 173 - Pollution studies
through the Curventon counting fence, 7 miles above head of tide.
In previous years the movement was predominately upstream with
only occasional salmon being caught in the down traps of the
counting fence. The sharp rise in the number of descending
salmon together with the observation that many were resting in
full view above the counting fence led field personnel to suspect
pollution from a mine on a tributary river. Our observations
and records during the spawning migration of 1961 are similar
to those reported for 19oO. The relation between the numbers of
salmon moving up and downstream past the Curventon fence for the
past 8 years are summarized in Table I.
Table I. Movement of adult salmon past the Curventon counting
fence.
Grilse
Large salmon
Iesu: HQ. u;g HQ. QQ~D dLu. :i:t lQQ No. Yl2 HQ. go~n slLY. A lQQ
*1954 2,600 37 1.4 1,081 5 0.5
1955 2, 756 58 2.1 778 11 1.4
*1956 775 14 lo8 587 13 2.2
*1957 875 38 4.3 706 7 1.0
1958 2,420 61 2.5 580 12 2.1
*1959 7,355 40 0.5 1,002 11 1.1
*1960 2,775 665 24.0 376
10.4
1961 978 85 8.7 866 19.4
*Fence washed out for short periods)by floods
The difference in the down-up ratios for grilse and
large salmon may be explained by the time at which these fish
reach the fence. In 1961, many large salmon moved upwards
through the counting fence during the third week of June; few
grilse appeared at this time. This was the period when pollution
was high as described in the next summary, and many large salmon
moved downstream. Later, .when the numbers of large salmon and
grilse were nearly equal, there were about equal numbers of each
moving downstream.
In 1960, 22% and in 1961, 21% of the adult salmon
were tagged as they went downstream past the fence. It is
interesting to consider the fates of these fish. These are summarized
in Table II.
li~

Pollution studies - 174 -
Table II. Fates of adult salmon tagged as they moved down river
through Cnr1rentan cmmt i ng fence.
Subsequently returned
to counting fence and
went upriver
Not heard of again
Caught by angling or
commercial net in NoW.
Miramichi Rn at some
point below Curventon
fence
1960
Number Percentage
of fish of total
70
64*
Angled in other rivers 8 5.1
(Sevogle R.)
1 Oo6
(S.W. Miramichi R.)
13
Totals 156 100
1961
Number Percentage
of fish of total
22
27
4
1
( Sevogle R. )
54
ltoo 7
50.0
*Two of these were caught in N.W. Miramichi commercial nets in 1961
Of particular concern are those descending fish which
were not heard of again. Two possible explanations for their
failure to return upstream are: (1) They were Sevogle River fish
which strayed half a mile past the mouth of their parent stream
but later returned to the Sevogle River; (2) They were N.W.
Miramichi River fish which were deterred by the mining pollution
from completing their spawning migration to the upper parts of
that rivero It is likely that more than the number recaptured
in the Sevogle River did enter that river either as a home river
or as an alternate to the N.Wo Miramichi. A reasonable argument
against extensive wandering of this kind is the record for
previous years which shows that few salmon returned downriver
during the summer after having passed the Curventon fence.
Furthermore, it is significant that in both years greater numbers
of descending fish were caught in the lower reaches of the N.W.
Miramichi than in the Sevogle River. Therefore, we believe that
in 1960 and 1961 considerable numbers of main-stem N.W. Miramichi
salmon were lost from the spawning stock of that rivero
100
R.L. Saunders

No. 77 - 175 - Pollution studies
A NEW METHOD OF ESTIMATING THE DEGREE OF MINING POLLUTION
WHICH DISTURBS SALMON MIGRATION
In 1960, an index of the "safe" level of mining
pollution in the Miramichi was tentatively estimated to be 0.06
mg/1 of zinco Although this estimate has been useful as a
yardstick for pollution control measures, it is undoubtedly an
over-simplification. For example, it is known that zinc and
copp~r become much more toxic when water hardness decreaseso
Furthermore, the proportion of copper to zinc in the Miramichi
is likely to vary, and copper is much more toxic than an equal
concentration of zinc. The same sort of relations probably
apply to sub-lethal effects of zinc and copper. In order to
provide a valid scientific estimate of the level of heavy metal
pollution which affects salmon migration, it is desirable to
integrate all the important variables of water quality into a
single number or index.
This has been attempted by adapting a system developed
in the British Water Pollution Research Laboratoryo Although
they have not used the system for sub-lethal effects, they have
been successful in estimating the combined toxicity of two or
more poisons acting jointly8 The starting point for calculations
is the "threshold" lethal concentration, that is, the greatest
concentration of poison which just fails to kill fish. This
threshold concentration is known from laboratory worko Any given
concentration of poison is then expressed as a fraction of the
threshold, or a multiple of it.
Accordingly, threshold concentrations for zinc, and
for copper, were calculated on a daily basis for the Northwest
Miramichi River in 1961. These thresholds depended on the dayto-day
changes in water hardness. Actual concentrations of zinc
and copper in the Miramichi were then expressed as fractions of
the thresholds, and the two fractions were added together for a
given day. For simplicity, this single number for degree of
pollution is hereafter called the "toxicity index"o
In Figure 2, the toxicity index is plotted along with
salmon movements at the counting fence at Curventono It is seen
that there is abnormal downstream movement of fish whenever the
toxicity index is greater than about 0.15, that is, 15% of the
lethal levelo In addition, normal upstream movement may have
been delayed, but this cannot be assessed with certainty. There
was apparently little disturbance of migration when the toxicity
index was below Onl5. This conclusion applies fairly well for
both spring and autumn runs of salmon. For contrast, absolute
concentrations of zinc have been plotted on the same grapho
Last year's estimate of a "safe" level of zinc correlates with
salmon movements during the autumn run, but not during the spring
run. In June there was disturbance of migration when zinc was at
supposedly "safe" levels. The toxicity index gives a much better

0·3
~
X
l&J
o o.2.
z
Atporen t " Sate ,, k vel
>-
!:: 0.1
u
~
F-
~
0-1------------
~
~ o.l
........
p
u
2
N
0
~
z
s
~ UPSTREAM
a DOWNSTREA.M
r
~
:A
0-
60-
40-
:zo-
20-
?
, - 8ack9round
---'----
Prelimmury "safe'' estimate
'
_J_ to 0.22
APRIL I MAY I JUNE I JULY I AUGUST I SEPIEMB£R I OCTOBEI~ ' NOVEMBER I DECfM6£R
Figure 2o Degree of heavy metal pollution compared to salmon migration at Curventone
In the lower panel, last year's "safe" estimate fails to explain abnormal downstream
'1lovements in Juneo In the upper panel, s~mmation of both zinc and copper fits salmon
jshaviour better. Apparent correlation of upstream movement with increased pollution
~erely indicates that both tend to occur during freshets.
_,0
-ofo
-2o
-o
-20
"t1
0
~
~
~
cT
1.4
g
CJl
cT
~
p.
1.4
(I)
CJl
~
-....:J
()\

- 177 - Pollution studies
correlation--it was high in June because of soft water and
because there was proportionately more copper pollution in
relation to zinc.
The present application of this ingenious British
approach is somewhat deficient·in accuracy because several
approximations were used to a:r~ive at the toxicity index for
each day. The threshold toxicities used were those for rainbow
trout determined by the British Water Pollution Research
Laboratory. However, spot-che¢.ks for toxicity of zinc to salmon
were carried out at St. Andrews and agreed precisely with the
data for rainbow trout. The'modifying effect of water hardness
was interpolated from only two~or three experimental values.
The extremely low concentratioqs of copper in the Miramichi could
not be analysed chemically w~~~ sufficient accuracy, but were
calculated from higher copper.concentrations in the polluted
tributary, using daily diluti6ti ratios. In spite of these
approximations, integration of the three measures of water quality
gives a more valid estimate of'degree of pollution than would be
obtained if any one of the three were ignored. It is recommended
that this type of index should be used to judge the effectiveness
of pollution control at the mine, especially since a new type of
ore is to be processed which.eontains more copper.
It should be noted that the exact reason for disturbance
of salmon migration is still not explained. It may be a true
avoidance of the polluted water, a weakening of swimming
performance, or possibly the fish are confused as to whether they
have reached their home stream. Laboratory experiments are
planned for the summer of 1962 to attempt to explain this
mechanism.
No. 78
HEAVY METAL POLLUTION
LETHAL AND SUB-LETHAL EFFECTS ON YOUNG SALMON
J. B. Sprague
From the first of June until December 10, 1961,
salmon parr were held in cages at four places in the Northwest
Miramichi River, one of the cages being a control upstream of
the pollution. In addition fish were sometimes held at two
locations on the Tomogonops River systemo The program was
conducted jointly by Department of Fisheries and Fisheries
Research Board. Water samples: were taken regularly at each of
the sites and analysed for heavy metals, and general water quality.
In addition to serving as a good monitor on pollution, the tests
with live fish served two purpos~s: (1) to determine whether
zinc and copper were the only important toxic components in the
water; and (2) to see whether sub-lethal levels of pollution
affected well-being of fisho

Pollution studies - 178 -
Direct lethal action by copper and zinc w~s indicated
for five groups of fish~ including some tests carried out the
previous yearo · Each of these bioassays had an accurate estimate
of the actual time to 50% mortality (the 50% lethal time, or th~.
"LT50"), and an adequate series of chemical analyseso For each
test, the theoretical lethal effects of zinc and copper were
calculated from the water analyses by means of the "toxicity
index" method described in the previous summaryo In all five
cases, the theoretical LT50°s were in excellent agreement with
the actual times of death of the caged fish. This is taken as
evidence that copper and zinc were the only important deleterious
substances in the watero It is of interest that the contribution
to toxicity by copper was about equal to that by zinco
In addition to the tests mentioned above, some anomalous
results were obtained from bioassays in the Little South Tomogonops
River, only half a mile downstream from the mineo Fish lived
here for extended periods in high concentrations of metals, as
long as the pH remained high because of lime added to the water.
This effect of high pH was substantiated by work at Sto Andrews.
Laboratory tests showed that the toxicity of zinc was slightly
reduced at pH 8o2, and greatly reduced at pH 9o0, survival times
being "infinite" at a concentration of zinc which normally killed
in 10 hours at neutral pH~ Occasionally the pH was near-neutral
in the Little South Tomogonops, and on these occasions, fish
died much more rapidly than could be accounted for by the
concentrations of zinc and coppero This phenomenon is not
explained, but may be because of the presence of other toxic
materials which settled out of the water before it reached the
Mlramichi, or disappeared in some other mannero
For most of the season, caged fish in the Miramichi
were subjected only to sub-lethal levels of zinc and copper
pollution. During tests in June and July, the fish were not fed.
Results were the same for the control fish as for two groups
exposed to different degrees of pollution. All ~parently starved
to death, with LT50 1 s close to 30 days, and not statistically
differento Although no sub-lethal effects of pollution were
apparent, the measured effects of starvation on condition of the
fish were useful for assessing later experimentso
In tests run from late July to December~ fish were fed
hatchery food to which they had been accustomed. Results were
again much the same for the control fish and for groups exposed
to sub-lethal pollutiono All groups lived successfully, and grew
equally. Condition factors of the fish, a measure of "plumpness",
were also similar in all cages. The levels of pollution
experienced were variable, but in the most severe location, they
averaged about 10% of the lethal level during the warm season
and about 20% during the autumno The levels of 10% and 20%
bracket. the apparent maximum for undisturbed salmon migration,
but did not seem to have any harmful effects on caged young

- 179- PollutiQn- studie-ssalmon.
During the-seasen, ther~ were occasional increases of
pollution to high sub-lethal levels, and at these times fish showed
little interest in foodo
One anomalous result has been excluded from the above
discussion, and is not yet explainedo A group of fish i-ediately
downstream of the mouth of the Tomogon.ops River showed progressive
regular mortality when the toxicity index for zinc plus copper
was very low, in the range from 0.05 to Ool5. Although the LT50
was 30 days, corresponding to the time for death by starvation,
the average condition factor of these dead fish was 0.95, high
enough to indicate that starvation was not the cause of death. A
condition factor of only Oo64 was typical of fish which bad
starved to death in earlier experiments, while thin fish with a
condition factor of 0.88 had remained alive. During the 13-day
period when these unexplained deaths were occurring, fish stopped
feeding, suggesting that a lethal factor was operating. The
seasonal low in river flow occurred at the same time, and high
water temperatures for part of the period may have been an
accessory factoro It is possible that deaths may have been caused
by the summation of stress from sub-lethal pollution and f~om
high temperature or a similar factor.
No. 79
HEAVY METAL POLLUTION
EFFECT ON FISH FOOD ORGANISMS
J. B. Sprague
The most numerous macroscopic invertebrates in
unpolluted parts of the Northwest Miramichi River are the young
stages of midges, mayflies, caddisflies, and at times blackfly
larvae. Of these types, mayflies and caddisflies make up by
far the greatest part of the biomass available for fish foodo
In 1960 metal pollution caused virtual disappearance of mayflies
from 15 miles of the Northwest Miramichi, and a depression in
numbers for at least another 3 miles. Caddisflies were much less
affected--they are known to be more resistant to heavy metals.
Pollution w~s somewhat alleviated during 1961, and this was
reflected in a general improvement in kinds-and numbers of
invertebrates in the rivero
Sampling of aquatic invertebrates in the mouth of the
Tomogonops River itself- was indicative of the general_ improvement.
This lo~ation was almost barren of invertebrates in 1960,
and the same condition continued through June and July of 1961.
When concentrations of zinc anc copper were at their minimum in
August, large numbers ef midge and blackfly larvae were found,
and fair numbers of caddiso However, when pollution worsened
during the autumn, only a few invertebrates remained alive in the
mouth of the Tomogonops. Water from the Tomogonops mixes fully

Pollution studies 180 -
across the Miramichi in a few miles at times of low flow, and
hence only a short section of the main river would suffer this
severe reduction or invertebrates.
From 2 miles downstream of the Tomogonops to 15 miles
downstream, the Northwest Miramichi does not receive any large
tributaries to dilute the pollution. Aquatic invertebrates
were sampled at two locations in this section of river. Both
stations showed extreme scarcity of mayflies last year, and
this situation had changed little in the spring of 1961. Numbers
increased during the summer, and, during August to November, were
approaching populations at control stations. On the average
during this period the control areas had about 2o5 times as many
mayflies as the polluted areas for a given area of river-bed. On
the other hand 7 caddisflies had increased in the polluted section,
from slightly depressed numbers in early summer to great
abundance in the autumno They averaged about 2.5 times the
number at unpolluted stationso The reason for these relatively
large populations is not known.
Fifteen miles downstream of the Tomogonops mouth,
pollution is diluted by the entrance of the Sevogle River.
Downstream from here 7 numbers of mayflies had been somewhat
reduced ln 1960 9 hut by the autumn of 1961, had climbed to 70%
of the average number at control stationso Here again, there were
about 2o5 times as many caddis as at unpolluted stations.
Thus the shortage of fish food organisms in early
summer had markedly improved by the end of 1961. By this time
total biomass of insects available for fish food was good.
However, if the type of food is considered, the supply of mayflies
as a group was somewhat reduced for 15 miles of the Miramichi.
There were greater differences at the species level
which have not been discussed above. Further study of these
differences is planned so that these invertebrates can be used as
a monitor of heavy metal pollution in other areas of the
Maritimes.
No. 80
RELATION BETWEEN BASE METALS MINE EFFLUENT
AND PRODUCTION OF YOUNG SALMON
J.B. Sprague
The relatively low production of young. salmon .in that
part of the Northwest Miramichi receiving heavy metal pollution
from mine workings was reported last yearo
Table III gives the average numbers of 3-size groups
of young salmon per 100 square yards of stream bottom as found in
3 years before D.D.T. had any bad effect, and in the ~ years

•.- 181 -
Pollution studies
since there has been no D.D.To spraying on this watershed. In
1958, recovery from D.D.T. spraying should have been evident in
increased numbers of underyearlings. The relative scarcity of
underyearling fish in the upper reaches probably reflects a
barrier effect of extensive pulp-log driving during the 1957
spawning season. By fall of'l958, however, conditions appear to
have been satisfactory for qi~tribution of spawner~ and spawning
activity. The 1959 young salmon population in the upper and lower
reaches appeared to have retu~ed to the pre-spray level.
Underyearlings were derived from a 1958 run of 3,000 adults of
which over 2,100 went to the upper half of the river and nearly
900 stayed in the lowero The 1960 population of underyearlings
was derived from a much larger run of nearly 8,400 adults of which
5,400 went to the upper half.and over 2,900 stayed below. This
did not, as might have been expected, result in a better population
of underyearlings in the lower river sampling stations, which are
all within the area affected by the mine effluent in 1960. Again
in 1960, over 2,400 adults entered the river and just over 650 went
to the upper part, leaving nearly 1,800 below. Although nearly
twice as great as the 1958 spawning stock in the lower river,
this produced only one quarter as many underyearlings in 1961. It
seems reasonable to associate these low populations derived from
reasonably good spawning runs with the demonstrated toxic effects
of the mine effluent on all stages of young salmon.
Table III. Average numbers of young salmon per 100 square yards
of stream bottom found in the Northwest Miramichi
River above (6 stations) and below (4 stations) the
base-metals mine effluent brought in by the
Tomogonops River. Underyearlings--fish of the year;
small parr--10 em and under; large parr--over 10 em
snout to tip of tail.
Above Tomogonops
Fry
Small parr
Large parr
36
21
13
28
20
16
32
39
19
6
20
9
47
11
14
20
26
16
7
22
14
Below Tomogonops
Fry
Small parr
Large parr
8
7
3
17
18
5
8
12
3
41
1
3
15
30
2
1
7
2
4
3
1
In 1960, at least, the mine effluent was observed to
present a partial but definite barrier to the upriver movement of
spawners. The results of this are conspicuous in the 1961
populations of yo~g salmon. They can apparently be summarized
in the statement that the mine effluent prevented reasonable
numbers of spawners from reaching the upper half of the river, and

Pollution studies - 182 -
therefore gravely reduced future production from there. The
effluent also apparently killed eggs or newly spawned young fish
in the lower section of river, and probably some older p~rr.
In addition to drastically curtailing survival, there
is evidence of poor growth of those survivors remaining in the
mine-affected reaches. The 1961 condition is somewhat ameliorated
over the 1960 condition, however. Despite the fact that fish in
the upper, unaffected reaches were smaller in 1961 than their comparable
size-groups in 1960, nevertheless the fish in the lower
part were a little larger in 1961 than in 1960o They are smaller,
however, than fish of comparable size-groups above. This is the
reverse of the normal condition, in which fish of the warmer,
lower reaches tend to be l/2 to 1 centimetre longer than their
counterparts in colder headwaterso In 1961, yearlings from the
1960 hatch were relatively scarce in the lower reaches. Normally,
they should compose nearly 100% of the under 10 em size-group in
the lower reachesn In 1961, half of this small group were 2-year
old fish. By contrast, in the upper reaches in 1961, less than
one third of the small group were 2-year olds~
It would appear that, at least in 1961, attempts at
rehabilitation by introducing young hatchery stock would have
been premature, by reason of some dearth of suitable natural
food, especially during early summer.
Last winter (1960-61) evidence was obtained in laboratory
experiments to suggest that fish from the polluted waters were
weakened, so that their ability to withstand winter cold-water
stress was reduced to the extent that nearly all test fish died,
but no control fish died. Similar tests on fish collected in
late 1961 have demonstrated only a negligible amount of such
weakness.
P. F. Elson
No. 81
SURVEYS OF POSSIBLE POLLUTION IN ESTUARIES
Chemical surveys were undertaken by request of other
groups to determine the seriousness of pollution in Saint John
Harbour and in the estuary of the Miramichi River. Work in Saint
John was the final follow-up of conditions after a new oil
refinery had commenced operations" The most dangerous waste
product for fish was thought to be phenolic compounds, which
have been known to taint fish flesh when present in concentrations
of only 0.02 mg/1. Lethal levels are in the range of 1 to 10
mg/1 of phenol.
Sampling was done at 12 stations in Saint John Harbour,
and 4 stations up the estuary. Both bottom and surface water
were sampled. Erratic traces of phenol were found around the

- 183 - Pollution studies
harbour, up to 0.007 mg/1, but most samples had 0.003 mg/1 or
less, the limit of detection by this test. There was no evident
pattern which could be considered as a build-up of pollution and
subsequent dilution. No other effects on general water quality
were found.
The oil refinery was operating normally at the time of
the survey, according to their records. Factors which helped to
lessen the danger of pollution were: (1) a normal waste output
of 160 to 500 pounds of phenol per day, compared to a predicted
level of about 1,400 pounds per day; (2) a long diffuser outlet
on the waste pipe-line; and (3) great tidal dilution and mixing
in the area.
A biological survey of the bottom fauna was also
conducted for comparison with a survey before the refinery started
to operate. Use of these invertebrates as cumulative monitors
should indicate any serious spills from the refinery in previous
weeks or months. These collections of animals have yet to be
studied.
At sampling points up-river of Saint John, lignin
compounds and other materials from pulp mill effluent gave
slight positive readings in the phenol analyses, because of their
molecular structure. Good dispersion of this effluent was
indicated, with only slight depression of pH and dissolved oxygen,
or none at all, as far upstream as the mouth of the Kennebecasis
River.
In the Miramichi estuary, a similar lack of serious
pollution was found. Sampling covered 11 miles of the estuary,
centering on a pulp mill. There was some reduction of dissolved
oxygen in the immediate area of the pulp mill, 40 to 50 yards
offshore beside a boom of logs. At greater distances from the
mill, little effect on water quality was noted.
J.B. Sprague

FISHERIES OCEANOGRAPHY SUMMARIES
Number
Drift-bottle releases 1961 82
Preliminary analysis of driftbottle
recoveries 83
European recoveries of drift
bottles 1960-61 84
Scotian Shelf drift-bottle
releases in March 1959 85
Sea-bed drifter experiment 86
Bottom current measurements,
Pisa tubes 87
Deep water circulation in
Cabot Strait 88
Design of equipment 89
Coastal temperatures in 1961 90
Monitoring oceanographic conditions
on the Scotian Shelf, Halifax
Section, 1961 91
Bottom temperatures, Scotian Shelf
and Bay of Fundy area in 1961 92
Waters along the slopes of the
Laurentian Channel 93
Temperature and salinity conditions
of the waters in the northern sector
of Northumberland Strait 94
Long-term variation of water
temperatures 95
Long-term water temperature variations
and the resultant wind anomalies 96
Long-term temperature variations and
the cod-haddock ratio in commercial catches 97
Evaporation in the Gulf of St. Lawrence 98
Participation to ICNAF Environmental
Working Party 99
Library of oceanographic data 100
Page
185 - 188
188 - 195
195 - 196
196 - 197
197 - 199
199
200 - 201
201
201 - 204
204 - 205
205
206 - 207
208 - 209
209 - 210
211
211 - 213
213 - 214
214 - 215
215

No. 82
- 185 - Fisheries oceanography
DRIFT-BOTTLE RELEASES 1961
During the year drift bottles were released from
fixed stations and cruises along the Atlantic coast in certain
areas. Releases at fixed stations were made as follows:
a) 2 bottles once a day at Sambro Lightship, and at
Lurcher Lightship;
b) 2 bottles once a day at two stations from the ferry
boats CPS Princess Helene between Saint John, N.B.
and Digby, N.S., and CNR Abegweit between Borden,
P.E.I., and Cape Tormentine, N.B.;
c) 2 bottles once a day at three stations from the
ferry boat CNR William Carson between J·Torth Sydney,
N.S., and Po.rt aux Basques, Nfld.;
d) 2 bottles at two stations between Yarmouth, N.S.,
and Bar Harbor, Maine, from the ferry boat CNR Bluenose
each time she passes these stations, twice a day
during the summer schedule and once a day during the
other seasons;
e) 8 bottles at each of six stations, approximately once
a month between Saint John, N.B.,and Digby, N.S., on
CPS Princess Helene and also between Yarmouth, N.S.,
and Bar Harbor, Maine,on CNR Bluenose;
f) 24 bottles once a month on Prince Stations 5 and 6;
g) 2 bottles each time the Pandalus II occupied certain
stations in Northumberland Strait.
The releases during cruises varied between 6 and 30
per station, depending on the area covered and the density of
stations. This year the cruises cover almost exclusively the
Bay of Fundy and Gulf of Maine area.
From January to December 1961, a total of 7,120 bottles
were released at the fixed stations out of which 1,132 were
recovered. During cruises in 1961, a total of 4,693 bottles
were released from which a total of 926 were recovered. The
percentage of recoveries varied gredly with the area and the
season. The bottles released in the period April-June generally
have the highest percentage of recovery. A breakdown of the
releases, recoveries and yearly comparisons are given in Tables
I , I I , and I I I •

Fisheries oceanography - 186 -
Table I. Drift-bottle releases and recoveries, fixed stations
1961.
Station feriod Releases Recoveries Percentage
Sambro Lightship Jan. -D.ec. '576 66 11.4
Lurcher Lightship Jan.-Dec. 566 67 11.8
Princess Helene
Station #1 Jan.-Dec. 618 104 16.8
Princess Helene
Station #2 Jan.-Dec. 618 101 16.3
Princess Helene
Special Apr.-Dec. 432 68 15.7
Bluenose Station #1 Jan.-Dec. 702 68 9.7
Bluenose Station #2 Jan.-Dec. 707 71 10.0
Bluenose Special Mar.-Dec. 528 34 6.4
Pandalus #3, #5,
#18 May-Nov. 206 101 49.0
Prince Station #5 Jan.-Dec. 282 50 17.7
Prince Station #6 Jan.-Dec. 281 85 30.2
Abegweit Station #1 July-Dec. 356 131 36.8
Abegweit Station #2 July-Dec. 354 184 52.0
Carson Station #1 Aug.-Dec. 298 3 1.0
Carson Station #2 Aug.-Dec. 298 3 1.0
Carson Station #3 Aug.-Dec. 298 8 2.7
Grand Total 7,120 1,144 16.1

.. 187 - Fisheries oceanography
Table II. Drift-bottle releases and recoveries: Cruises, 1961
Station Month Area Releases Recoveries Percentage
HS-30 February Bay of Fundy 144 16 11.1
St. Mary Bay
HS-31 July Bay of Fundy
Gulf of Maine
516 196 38.0
HS-32 August Bay of Fundy 156 8 5.1
Gulf of Maine
St. Mary Bay
HS-33 August Bay of Fundy 438 67 15.3
Gulf of Maine
HS-34 September Trinity Ledge 30 2 6.7
Bay of Fundy
HS-35 November St. Mary Bay 324 46 14.2
Bay of Fundy
HS-36 Nov.-Dec. St. Mary Bay 288 43 14.9
Bay of Fundy
ATC-46 October Gulf of Maine 260 1 0.4
ATG-47 October Gulf of Maine 232 3 1.3
MPS-8 January St. Mary Bay 288 24 8.3
Bay of Fundy
MPS-9 February St. Mary Bay 192 29 15.1
Bay of Fundy
MPS-10 March St o Mary Bay 192 26 13.5
Bay of Fundy
MPS-11 March St. Mary Bay 192 76 39.2
Bay of Fundy
MPS-12 April St. Mary Bay 192 47 24.4
Bay of Fundy
MPS-13 May St. Mary Bay 252 93 36.9
Bay of Fundy
MPS-14 May St. Mary Bay
Bay of Fundy
216 77 35.6
MPS-15 June St. Mary Bay
Bay of Fundy
252 108 42.9
MPS-16 September St. Mary Bay
Bay of Fundy
265 49 18.5
MPS-17 October St. Mary Bay
Bay of Fundy
264 ____l2 5.7
Grand Total 4,693 926

Fisheries oceanography - 188 -
Table III. Drift-bottle releases and recoveries:
Comparison 1960-61
Cruises
Fixed Stations
Releases
1960 3,875
1961 4,693
Increase 818
1960 3,941
1961 7,120
Increase 3,179
Grand Total 1960 7,816
1961 11,813
Increase 3,997
Recoveries
616
926
310
783
1,144
361
1,399
2,070
671
Percentage
19.9
16.1
17.8
17.5
Co-operation of the masters and officers of the
following ships is acknowledged: Sambro and ;Lurcher Lightships,
CPS Princess Helene, CNR Bluenose, CNR Abegweit, and CNR William
Carson. Without their interest in this drift-bottle program,
and their effort, the drift-bottle releases at fixed stations
would be reduced by almost 90%.
No. 83
J. G. Clark
A. w. Brown
PRELIMINARY ANALYSIS OF DRIFT-BOTTLE RECOVERIES
The 2,070 recoveries from 11,813 bottles released in
1961 were concentrated in two main areas, the Gulf of Maine-
Bay of Fundy area and the Northumberland Strait in the Gulf of
St. Lawrence. The purpose of the drift-bottle program is to
follow the seasonal and the year-to-year variations of the
surface non-tidal drift along our coast. Emphasis has been given
to areas where plankton studies required a more detailed
knowledge of the circulation. The analysis of recoveries is
made on the area basis.
a) Gulf of Maine, Bay of Fundy,
and Western Scotian Shelf
The general surface circulation pattern as inferred
from drift-bottle releases and recoveries has been monitored
from daily releases at fixed points in the area. The largest
continuing series of releases was originated in November 1956
at Lurcher Lightship by the International Passamaquoddy Fisheries
Board. The accompanying figure represents the quarterly
recoveries from Lurcher Lightship for a 5-year period. The data
for the years 1957, 1958 and 1959 were taken from a previous
summary in A.O.G. Annual Report 1959-60 (Chevrier and Trites).
The quarterly recoveries as shown in this figure infer a

1957 1958 1959 1960
1961
w
I
N
T
E
R
s
p
R
.L
N
G
I
......
CX>
\.0
Quarterly recoveries from Lurcher Lightship 1957-1961
(number of releases and recoveries in top left hand
corners).
~s
u
M
M
E
R
A
u
T
u
M
N
"%J
~
(I)
::r
(I)
t1
~
(I)
(I)
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(I)
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::s
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(Jq
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'0
~

Fisheries oceanography - 190 ~
seasonal circulation pattern and deviations from it.
The winter recoveries from Lurcher releases infer a
rather restricted movement of the waters along the Nova Scotian
coast of the Bay of Fundy and to some extent towards the Quoddy
region. During the spring season, a wide spread of recoveries
in the Bay of Fundy as a whole suggests that the circulation has
gained momentum, becoming "open circulation" and continuing as
such during the third quarter. During the autumn, the movement
of the waters from Lurcher Lightship has a tendency to be more
restricted than during the summer. The recoveries are
concentrated along the Nova Scotian coast of the Bay of Fundy.
Each year seems to have a period which shows deviations
from the normal circulation pattern. In 1957 the spring and
summer circulation along the New England coast was characterized
by an apparent absence of recoveries from Lurcher releases. In
1958 the large number of recoveries during the winter season
inferred a strong counterclockwise circulation in the northern
Gulf of Maine. In 1959, the winter contribution from Lurcher
to the ~uoddy-Grand Manan region was greater than during the
other years. In 1960 and 1961 the absence of recoveries in the
Quoddy region during the spring was noticeable. In 1961, the
recoveries in Cape Cod area were higher than usual during the
autumn indicating a strong counterclockwise circul~on in the
Gulf of Maine late in the year.
The recovery data from releases made at the other
monitoring stations, Sambro Lightship 1
off Halifax, Princess
Helene #1 and #2, in the Bay oi· FundJ', and Bluenose #2 along
the coast of Maine, complement those from Lurcher by providing
more local and continuous information necessary for studying an
area as large as the eastern Gulf of Maine and the Bay of Fundy.
During the first quarter of 1961, the recoveries in
two sectors of the periphery of the Bay of Fundy, the N.S. coast
and the N.B. coast between Saint John and Grand Manan suggest a
close circulation and a rather slow movement of the water.
This pattern of recoveries differ from that of 1960 during the
same period when all the recoveries were made along the N.S.
coast.
During the second quarter of 1961 the largest
concentrations of recoveries were made in the upper part of the
Bay of Fundy, mostly along the N.S. coast. Few recoveries were
made west of Saint John along the N.B. coast and along the New
England coast as far as Cape Cod. In 1960, more recoveries have
been recorded during this quarter along the New England coast.
Another significant difference between 1960 and 1961 was the
recovery distribution from Sambro Lightshipo In 1960, as many
as 14 recoveries have been made west of Halifax and none east of
Halifax, while in 1961 five recoveries were recorded west of
Halifax and eight east of Halifax.

- 191 - Fisheries oceanography
During the third quarter of 1961, the recoveries-were
made fairly evenly around the coast from west of Halifax to Bay
of Fundy to Cape Cod, with a high proportion along the coast
of Maine. The main differences between 1961 and 1960 from July
to September were: high concentration of recoveries in
Chignecto-Minas Basin area in 1960, high concentration along the
coast of Maine in 1961, and almost twice as many Sambro
recoveries in 1961 as in 1960o
During the last quarter of the_ year, October-December,
1961, the main feature was the very large number of recoveries
in the Cape Cod area. These totalled 60 as compared to 1 during
the same period of the previous year~ These numerous recoveries
originated from every one of the fixed stations west of Halifax.
In 1960, a very large number of recoveries had been reported
along the Nova Scotian coast between Digby and Minas Basin, while
in 1961, only one-fifth of the number has been recorded. The
recoveries in the Passamaquoddy-Grand Manan area during the
autumn were more numerous in 1961 than in 1960.
In general, the surface circulation pattern in the Bay
of Fundy during 1961, as inferred from drift bottle recoveries
tended to be "closed" during the first 3 months and ~open~, , .
during the remainder of the year. The Gulf of Maine eddy in the
northern sector was apparently strong for a period longer than
usual.
b) St. Mary Bay
Based on 1960 and 1961 drift-bottle data, the contributions
from surrounding waters to St. Mary Bay, however small,
show a seasonal variation. The recoveries from Lurcher Lightship
and Bluenose #1 releases are the most frequent; they reach a
minimum during the second quarter of the year and a maximum
during the third quarter. On the average, only 1% of all the
recoveries from these two release stations are recorded for the
upper St. Mary Bay. Releases from other stations are also
recovered in St. Mary Bay--the stations are: Princess Helene
stations, Bluenose #2, ,Sambr.o Light·:~:.~p and Pr~nQ.e_S, station.
Princess Helene recoveries are more frequent in November and
December than in other months. Upper St. Mary Bay was taken as
the sector of bay northeast of the line Petit Passage-Church
Point.
From September 1960 to December 1961, 18 drift-bottle
cruises were carried out in St. Mary Bay and surrounding waters.
This special emphasis given to drift-bottle experiments in the
area was to complement the herring larvae study along the Nova
Scotian coast of the Gulf of Maine and Bay of Fundy. The
recoveries in St. Mary Bay and in adjacent waters from outside
releases as well as those of the 18 cruises are summarized on
a quarterly basis in the accompanying table. The results show
that recoveries from two periods of releases, April-June 1961

Fisheries oceanography - 192 -
and July-September 1961 seem to be those of contrasting
conditions. The recoveries from the other three periods do not
seem to show a systematic pattern of recovery.
No recovery has been recorded in St. Mary Bay from
Lu~.q_qer. and Bluenose #1 releases made during the April-June
period, while recoveries from the same releases reached a
Recoveries in St. Mary Bay in comparison with outside recoveries
from var1oy~ §OUrC~ .
Period
Release Recovery 1260 l26l
area area Se:Qt.-D~c 2 Jan.-Mar. A:Qr.-June JuJ.:t:-Sei2t. Oct 1 -Dec.
% % % % %
Lurcher lower bay 2.8 1.2 o.o 1.0 1.0
and upper bay 1.0 0.4 o.o 1.0 o.4
Bluenose outside 0.0 3·3 18.7 10.8 o.4
#1
Lower lower bay 8.3 11.3 1.5 2.1 2.5
bay upper bay 3.4 1.4 7.6 20.8 12.7
outside 4.4 2.2 l9o2 9.0 1.9
Upper in the bay 31.6 36.4 54.6 50.6 29.0
bay outside 0.6 o.o 4.2 4.2 2.2
Petit in the bay 1.9 9.1 6.7 7.4 o.o
Passage outside 9-3 3.0 36.7 7.4 7.4
area
Coastal Cape Sable to
waters Cape St. Mary 1.5
south lower bay 2.1
of Cape upper bay 2.4
St.Mary outside 8.5
seasonal maximum in the Bay of Fundy, the Quoddy area, and along
the coast of Maine. The bottles released in the lower sector
of St. Mary Bay in the April-June period had a minimum rate of
recovery in the area of release and a maximum outside St. Mary
Bay. The bottles released in the upper St. Mary Bay during the
same period had a maximum seasonal recovery rate in the area of
release as well as outside the bay. The bottles released in
Petit. Passage area show a maximum seasonal rate of recovery
outside St. Mary Bay and a rather low rate inside.
The recoveries in St. Mary Bay from Lurcher and
B uenose #1 releases made during July-September were normal
lv), while the recoveries outside the bay were still high,
although at nearly half the rate of those from the previous
quarter. The bottles released in the lower bay during the July­
September period show a maximum rate of recovery in the upper bay

- 193 - Fisheries oceanography
and a much reduced rate outside the bay. The bottles released
in the upper bay during the same period show a slightly
reduced rate of recovery in St. Mary Bay as compared to that
of the previous quarter. From Petit Passage releases, the
recoveries inside and outside St. Mary Bay were equal.
The recoveries made from April-June releases in St.
Mary Bay and the surrounding waters infer that the surface
circulation brings about a "flushing out" of the bay, during
that period. Contrasting conditions are inferred from recoveries
of July-September releases when contributions from outside
stations to St. Mary Bay and from the lower to the upper bay
reach a maximurn.
In April, the bottles "start to move" out of St. Mary
Bay area in the direction of the upper reaches of the Bay of
Fundy. The bottles released in the first week of May show an
increased movement with few of them reaching the Passamaquoddy­
Grand Manan area. From the releases made at the end of May, a
few more bottles reach the Passamaquoddy-Grand Manan area in
about 25 days. The June releases show a maximum proportion of
recoveries between Saint John and Grand Manan. The bottles
make the trip in less than a month, 23-29 days on the average.
The contributions of the waters south of Cape St.
Mary to St. Mary Bay as inferred from drift-bottle recoveries
were studied during the July-September quarter; they seem to
be twice as large as the contributions from Lurche~ and Blueno;e
#1 during the same period.
c) Quoddy Region
In 1961 as well as in 1960, drift bottles released
at every fixed station west of Halifax were recovered in
Passamaquoddy Bay. The Quoddy region is considered as one of
the three catch basins in the Bay of Fundy. It accumulates
recoveries from Sambro Lightship at a maximum rate of 1.7% of
the releases per season, those from Lurcher Lightship at a
maximum rate of 6.2%. During one season 11.8% of the bottles
released from Prtncess Helene #1 were recovered in Passamaquoddy
Bay. Recoveries in Passamaquoddy Bay from fixed stations
outside the Quoddy region reach a maximum during the third
quarter (July-September). The recoveries in 1961 were more
numerous than in 1960. From St. Mary Bay area, it has been
shown that the outside recoveries reached a maximum from releases
made during the April-June period. Less than half of this
maximum, 26 bottles out of 60, were recovered between Saint John,
N.B.,and Maine, U.S.A. Of this number, half were recovered in
Passamaquoddy Bayo Under the best conditions, only one-fifth
or one-quarter of the bottles that are known to "leave" St. Mary
Bay (by their outside recoveries) are recovered in Passamaquoddy
Bay.

Fisheries oceanography - 194 -
From Prince 5 station, the maximum rate of recovery
in Passamaquoddy Bay was 22.2% in 1960 (April-June) and 29.2%
in 1961 (July-September). From the bottles released in the St.
Croix estuary, in Passamaquoddy Bay, a maximum rate of recovery
outside the bfy, 9.7% was recorded for the bottles released
during the first quarter of 1960. The recoveries outside the
bay were much less in number during 1961 than during 1960.
d) Northumberland Strait
This drift-bottle experiment is made in co-operation
with the lobster investigation. The drift-bottle releases and
recoveries during 1960, indicated an easterly and northeasterly
movement of the waters in the northern sector of Northumberland
Strait. Only two of the 1960 recoveries were made south of Cape
Egmont. The releases had been made mostly in the eastern half
of the Strait. The 1961 rele~se program has been stepped up in
order to cover (1) the n9;r;th:western· Northumbe"rland Strait, (2) the
central sector of the Strait in the area Cape Tormentine-P~rt'
Borden. The results, as shown by the recoveries, are given under
two headings: the Pangalu§ series in the northern sector and the
Abegweit series in the central sector.
The Pandalu§ releases were more numerous and had a
slightly lower percentage of recoveries in 1961 than in 1960
(51% as compared to 59%). In 1961, over 70% of rul the recoveries
were made in the northern sector of the Strait, as compared with
only 49% in 1960. The number of recoveries along the N.B. coast
of the Strait was lower in 1961 than in 1960, even with more
releases in the western half of the Strait. As compared with
the recoveries of 1960, those of 1961 infer that the movement
to the south toward the central sector of the Strait was still
reduced. In 1961, less than 6% of the drift bottles were
recovered south of the line West Point-Buctouche, as compared
to more.than 15% in 1960. In 1961, there was no recovery south
of Cape Egmont. In 1961, as in 19oO, recoveries from the
Pangalus series were made at the Magdalen Islands and along the
north coast of P.E.I. However, these long trajectories were
less numerous in 1961 than in 1960, and also did not extend so
far in 1961. The travel time was approximately the same in the
two years.
A drift bottle could "find its way" from off
Richibucto to North Point, P.E.I. 1
in 5 days, to the Magdalen
Island in 20 to 25 days, to East Point, P.E.I., in 30 days and
to the west coast of Newfoundland in 55 days.
The Pandalus releases and recoveries in 1961 bring
further evidence of an easterly and northeasterly movement of
the surface waters in the northern sector of Northumberland
Strait and of a lack of movement of these waters to the south
through the Strait. There seems to be a counterclockwise eddy
in the area or at least a trough-like pattern of circulation
with the surface waters moving south along the N.B. coast as

- 195 - Fisheries oceanography
far as Richibucto, then turning east towards P.E.I. and then
northeast along the p.E.I. coast.
. The Abegweit releases had a very high percentage of
recoveries undoubtedly due to the prevailing SW winds and the
short distance between the two coasts. More than 70% of all
the recoveries were made in the central sector of Northumberland
Strait. Within this sector seven times more bottles were ·
recovered along the P.E.I. shores than along the N.B. shores.
Only 7% of all the recoveries were made to the north of the
central sector, with only one bottle recovered north of Cape
Egmont. The remainder of the recoveries, approximately 20%,
were made to the south of the central sector and outside
Northumberland Strait. The drift-bottle recoveries from the
Abegweit saries infer that the circulation of the surface waters
in the central sector is from the mainland to P.E.I. and also
toward the southern end of the Strait.
The two series of drift bottle releases and recoveries
indicate that the two "stocks" separated by as little as 50 miles
do not "intermingle". There seems to be between them an area or
little water movement to and from. This area is one of very
little tidal amplitude (a near minimum for the Strait). The
inferred movements of water described here are those induced by
late spring, summer and autumn conditions only.
e) Cabot Strait
The three stations in Cabot Strait serve to monitor
the non-tidal drift in the main opening of the Gulf of St.
Lawrence to the ocean. The rate of recovery of the drift bottles
released daily is very low. A total of 14 bottles have been
recovered from 894 releases. Most of the recoveries come from
the east coast of Cape Breton and along the outer coast of Nova
Scotia. The longest trip by a bottle released from Kllliam
Carson so far started off Sydney, C.B., and ended just south of
Yarmouth, N.s., after a maximum of 61 days. Tw~ recoveries
south and west of Newfoundland have been recorded.
No. 84
EUROPEAN RECOVERIES OF DRIFT BOTTLES 1960-61
L. M. Lauzier
J. G. Clark
Drift bottles released along the Canadian Atlantic
Coast in 1960 have been recovered on the shores of Ireland
Scotland and Norway. The minimum travel time as computed from
the date of release in the northeastern sector of the Gulf of
St. Lawrence and the date of recovery on the north coast of
Ireland was 340 days •. This particular bottle travelled at an
average minimum speed ~r 5.9 miles a day. However, a faster

Fisheries oceanography - 196 -
trip was accomplished by a bottle released off Cape Sable, N.S.,
and was recovered 350 days after, along the east coast of
Scotland travelling at an average minimum speed of 7.1 miles a
day.
The European recoveries came from four particular
areas of release, the southwestern Gulf of St. Lawrence, the
northeastern Gulf of St. Lawrence, the Halifax area and Cape
Sable-Yarmouth area.
By comparison of recoveries of "sister" bottles,
those released at the same point, and at the same time as the
bottle which crosses the Atlantic, it seems that 3 out of the 7
bottles recovered along the European coasts escaped out of the
Gulf of St. Lawrence via the Strait of Belle Isle.
Two of the recovered bottles released 110 miles off
Cape Sable had their point of release 10 miles apart on the same
day. Both bottles were recovered within 8 days of each other,
with their locations being 250 miles apart on the shores of
Scotland and Ireland, respectively.
A true estimate of the proportion of bottles that
cross the Atlantic is difficult to make. From the Gulf of St.
Lawrence releases, t.he percentage of European recover~es was
of the order of 0.6%, from Cape Sable area it was 0.5%. These
percentages are relatively low as compared with the 1.3%
reported by Trites and Banks for the Scotian Shelf releases in
19?4. From earlier releases, in 1922 and 1923, made in
similarly located areas, 2.3% and 1.7% recoveries had been
reported along the European shores. It is believed that the
type of bottles used in earlier releases were different from
those released recently. These earlier releases including those
made in 1954 were fitted with drags at the point of release.
A detailed study of European recoveries from driftbottle
releases along the Canadian Atlantic coast is in
preparation.
No. 85
L. M. Lauzier
SCOTIAN SHELF DRIFT-BOTTLE RELEASES IN MARCH 1959
In the course of two A.T. Cameron cruises in March
19,9, 430 drift bottles were released in a grid pattern between
the Nova Scotia coast and Emerald-Sable Island Banks. These
releases were carried out in support of a groundfish egg and
larvae distribution study.
It is imperative to ana~yse the distribution of
recoveries from these releases before commencing the proposed

groundfish eg~and
- 197 - Fisheries oceanography
larvae-circulation project.
. From March 1959 until February 1960, only 5.1% of
the bottles have been recovered. Out of the 22 recoveries, 6
were made on Sable Island and one at sea. All but two of the
bottles recovered along the Nova Scotian coast, were released
at stations within 40 miles from the coast. Of the 6 bottles
recovered on Sable Island, 5 came from stations at least 70
miles from the coast. The recoveries stiggest a westerly movement
of the coastal waters and an easterly movement for the waters
over Emerald Bank and Sable Island Bank.
This phase o£ drift-bottle experiments in 1959 were
carried out in co-operation with the Atlantic Oceanographic
Group (R.W. Trites) and Woods Hole Oceanographic Institution
(D. F. Bumpus).
No. 86
SEA-BED DRIFTEH EXPERIMENT
L. M. Lauzier
Four series of sea-bed drifters have been released
during 1961 over the Magdalen Shallows and the entrance to the
Bay of Chaleur. The "Woodhead" sea-bed drifters, developed at
Lowestoft, England, have been used.
Number Recovered
Within 5
No. miles of pt. On
Cruise Date released Total
o'
-A._ of release beacn
GRF-33 May 24-26 168 26 15.5 5 1
GRF-34 May 30-Jun. 7 88 16 18.2 1 3
S-56 July 27 180 4 2.2
S-60 Nov. 12 120 0
These drifters are recovered by fishermen while
dragging for groundfish and it is presumed that very few of
the fishing vessels have positioning equipment. The accuracy
of the recovery position depends upon the ability of the
fisherman to fix his position upon recovery of a sea-bed
drifter. The rate of recovery is also a reflection of the rate
of fishing. The releases of Sackville cruises S-56 and S-60 .
were in areas where presumably little fishing was done at the
time. It is suspected that few recoveries will be made before
spring, 1962.
The accompanying figure is a composite picture of
all the recoveries and the points of release from the first
three cruises. Recoveries made within 5 miles of the release
point are not included.

Fisheries oceanography
- 198 -
QUE.8£C
I ,,,..... ~.,.,.~
,.,, .... p .. ~·~~·t;
........... , •• :f•"•,.J .....
_ ..... -ITo
N. a.
Recoveries or sea-bed drifters released between Mar 24
and July 29, 1961.

- 199 - Fisheries oceanography
. / There are indications from this figure that along the
Gaspe side of the entrance to the Bay of Chaleur, the bottom
waters are drifting in a southwesterly direction as part of an
eddy with a return current along Orphan Bank. The computed
bottom drift is very variable, between 0.08 and 2.8 miles per day.
The most frequent minimum drifts were of the order 0.14 and 0.28
miles per day.
1. M. Lauzier
No. 87
BOTTOM CURRENT MEASUREMENTS, PISA TUBES
From May 17 to 27 and from May 30 to June 7 bottom
current measurements with Plsa tubes were carried out from MV
Harengus in the Gulf of St. Lawrence. During the first cruise,
GRF-33, the measurements were made at two anchored stations,
one for a period of 24 hours on Orphan Bank and the other for a
period of 15 hours S.E. of Magdalen Islands at a depth of 34
fathoms. The latter station had been planned as a 24-hour
station, but ice conditions forced the vessel to move away from
the area. Bottom current measurements were also taken in the
warm deep layer of the Laurentian Channel in Cabot Strait.
During the second cruise, GRF-34, a groundfish survey cruise,
current measurements were carried out but at each fi&hi:ng ~station.
The results from the anchor station on Orphan Bank
showed fairly strong currents for a couple of hours at the
beginning of the series of observations and, for the next 21 hours,
current speeds were about one-third to one-half of the preceding
values. A storm surge just previous to the period of these
measurements has been suspected of this anomaly considering the
weather conditions at the time. According to data supplied by
the Canadian Hydrographic Service, the mean (24-hour) sea level
had shown some unusual oscillations between May 19 and 26. There
is an association between a change in sea level and unusual current.
Harmonic analysis of the above-mentioned measurement
was conducted by Commander W.I. Farquharson of the Canadian
Hydrographic Service and the results of these measurements
compared with those obtained subsequently by the Servive from 15
days of continuous observations in Gaspe Passage during June.
Observations taken within the warm deep layer of
Laurentian Channel and during the groundfish survey cruise were
carried out for the purpose of finding the order of magnitude of
the speed at various depths. The magnitude of the speed as an
environmental factor is just as important as the resultant current.
At 250 fathoms, in the Laurentian Channel, currents of 0.11 knots
have been observed. At the entrance of the Bay of Chaleur, the
observed bottom currents varied between 0.13 and 0.34 knots.
Messrs J. Clark and P. Powles were in charge of Harengus
cruises GRF-33 and GRF-34 respectively. Mr. V. Kennedy made all
the computations of the Pisa tube current measurements.
L. M. Lauzier

Fisheries oceanography - 200 -
No. 88
DEEP WATER CIRCULATION IN CABOT STRAIT
. Previous calculations of volume transport in Cabot
Strait by dynamic methods, for a large number of sections during
all seasons, have shown a fairly consistent pattern of circulation
within the deep layer, on inflow into the Gulf. The
shortcomings of the method and the limitations of the
assumptions are fully realized.
Defant's treatment of the problem of currents in a
sea strait brings additional insight to the study of the
circulation in Cabot Strait. Defant considers the circulation
in a sea strait connecting an inland sea and the open ocean as
a two-layer system. In a general way, the interchange of water
between the two bodies of water occurs at two different levels.
There are always two currents in the strait, one above the other
or, if the strait is wide enough and the current strong enough,
they might be side by side at certain levels. Defant considers
the currents in a sea strait as resulting from the difference in
the vertical thermohaline structure of the waters of the open
,ocean and the waters connected to it by the strait. The density
differences are the source of the energy which maintains motion
in the strait.
An almost constant inflow of deep waters into the
Gulf through Cabot Strait has been suggested by Lauzier and
Trites as resulting from the density distribution in the
Laurentian Channel.
Defant has developed a model applicable to the
conditions observed in Cabot Strait with certain reservations.
He arrives at a mean velocity of the two currents expressedl·.in
terms of the mean density of the two vertical columns at ·each
end of the strait, the dimensions of the strait and a frictional
resistance term.
The data available for testing this model are very
scanty. However, data from 3 cruises have been used by considering
the water columns in the center of the channel, away from "side
effects" (Coriolis effect) such as accumulation of low salinity
waters along Cape Breton. The mean velocities were of the
order 8 em/sec, a value which seems to be too high for a mean
velocity of the bottom layer, but not so for all of the
inflowing current which in many cases may occupy half of Cabot
Strait even at the surface.
Under such conditions, the mean densities of the water
columns in each body of water should probably be interpreted as
the mean densities of the cross sections. A modified model, for

- 201 - Fisheries oceanography
a wide strait .based on the principles defined by Defant, could
be developed. Such a model used for assessing the average
contributions of each layer or current would be most valuable
in energy budget of the waters of the Gulf.
No. 89
a) Ascending drift pole
DESIGN OF E~UIPMENT
D. G. MacGregor
L. M. Lauzier
The purpose of the ascending drift pole is to measure
the integrated drift of various layers of a body of water.
Such a drift pole was designed and trials have been conducted.
The pole is an empirically balanced system that maintains a
rate of ascent of about 5 em per second. It is constructed like
our usual radar drift pole with attachments underneath the twoplane
drag: a small sea anchor and a one-metre plankton net.
During the trials in Passamaquoddy and the Bay of
Fundy the forced descent and free ascent were monitored with an
echo-sounder. The deepest cast at 66 metres was carried in the
Bay of Fundy. It is the intention to use this type of drift pole
in the Laurentian Channel. Further trials are necessary to
determine the limits of accuracy of this method of drift
measurements.
b) Multiple drifters
The idea of using a double drift bottle is not new.
The double drift bottle operates on the principle that one
bottle is detached after a predetermined period of surface drift.
This single bottle goes to the bottom of the sea waiting for
recovery by draggers. It is used to make a point on the
trajectory of the other bottle which continue~ to drift at the
surface. It is proposed that magnesium wire be used as timerelease
device and plastic sea-bed markers be used instead of
bottles. Design of sea-bed markers has been made and magnesium
links are being tested.
No. 90
COASTAL TEMPERATURES IN 1961
1. M. Lauzier
J. G. Clark
Twice daily monitoring of surface water temperatures
at six shore or coastal stations along the Canadian Atlantic
coast continued during 1961. A supplementary series of bottom

Fisheries oceanography - 202 -
temperature observations, taken once a day were also continued
at Lurcher Lightship. This series was started in 1950. Only
a partially complete series of observations were available in
19ol from both Lurcher and Sambro Lightships due to annual
refits and necessary repairs. The longest continuous series of
observations along the Canadian Atlantic coast is that taken at
St. Andrews, N.B., commencing in 1921. These continued
observations are necessary to follow the year-to-year trend of
temperatures and to establish the basis for the study of the
marine climate of the area.
Observations of surface temperatures at all stations
during the year revealed a general decrease from the 1960
values. This decrease being maximum during the first 6 months.
During the latter half of the year three stations, Halifax
Harbour, Entry Island and Port Borden,recorded an increase over
the corresponding values for the previous year, with Halifax
Harbour showing the greatest variation. All six stations, with
the exception of Halifax Harbou~ showed a marked decrease in
temperatures when compared to the 10-year period 1950-59.
In the Bay of Fundy area the temperatures at St.
Andrews, N.B., were generally below both the long-term (1921-
1959) average and the average of the last decade (1950-1959).
This variation was most pronounced in comparison with the
10-year average when all months, with the exception of December,
showed a decrease notably during the first-8 months of the year.
Surface temperatures at Lurcher Lightship also showed a
generally marked decrease throughout the year from both the
long-term and the 10-year average. However, the long-term
average at Lurcher Lightship is based on 17 years of observations
as compared to 40 years at St. Andrews.
Temperatures along the outer coast of Nova Scotia
were monitored in Halifax Harbour and at Sambro Lightship. For
the first 6 months of the year the surface temperatures in
Halifax Harbour were without exception below the long-term
averages. The latter half of the year provided a marked increase
in temperatures, raising them above both the long-term and
10-year averages for this time of the year. Sambro Lightship
temperatures varied in much the same way as those of Halifax
Harbour for the first 7 months of the year~ August temperatures
were much below average because a prolonged period of upwelling
took place during the second half of the month, reducing the
surface temperatures by as much as 5° below average. Complete
records for the last 4 months of the year are not available.
Temperatures at Entry Island, ~uebec, and Port Borden,
P.E.I., showed that the temperature of the surface waters in the
southwestern Gulf of Sto Lawrence tended to be below normal
during the first half of the year. Late summer and autumn
temperatures, however, showed an increase over long-term averages.
May temperatures at Entry Island and Port Borden were respectively

- 203 - Fisheries oceanography
2.5°C and 6.0°C below the long-term averages. At Port Borden in
June the surface temperature increased steadily from 5.5°C to
13.0°C over a period of 25 days.
Table I shows the monthly mean surface temperatures
at the six coastal stations, their average variations from the
previous year and their deviations from the 1950-1959 average.
During 1961 bottom temperatures at Lurcher Lightship,
listed in Table II, indicate below normal temperatures throughout
the year. Although a slight increase in temperature over the
previous year's readings took place in the autumn, monthly
averages were consistently below the 1950-59 average. The forecast
of St. Andrews annual temperature for 1961 was 7.0°C and
the observed value 6.8°C. The forecast for 1962: St. Andrews
temperature will be near average, with an annual temperature
between 6.8 and 7.0°C.
Table I. Monthly water temperatures along the Canadian Atlantic
coast, 1961
St. Lurcher Sambro Port
Andrews Light- Halifax Light- Entry Is. Borden
N.B. shiQ Harbour shiQ Que. P.E.I.
Jan. 1.5 (4.3) 2.4 1.7 -1.0
Feb. 0.3 1.7 0.5 -0.9 -1.2
Mar. 0.8 1.3 -0.9 -0.7
April 2.6 1.8 2.1 -0.1 -0.2
May 6.0 3.7 5.6 3.6 2.4 1.3
June 9.3 9.2 6.2 7.5 9.2
July 10.9 8.6 13.2 13.0 14.2 --
Aug. 12 0 4 9.4 15.6 14. 7 17.5 17.6
Sept. 12.9 10.0 16.7 17.5* 15.8 17.0
Oct. 10.9 10.5 13.2 11.8 13.7
Nov. 8.3 10.6 7.0 7.9
Dec. 5.1 7.1 7.7 2.1
Average monthly temperature variation from 1960-61
Jan.
to June -1.1 -1.0 -2.2 -2.0 -4.9(2 mo.) -2.4
July
to Dec. -0.2 -0. 7(3 mo.) +1.4
+0.2 +0.3
Jan.
to Dec. -0.7 -0.9(8 mo.) -0.2 -1.2 -1.2
Average monthly temperature deviation from 1950-59 mean
Jan.
to Dec. -0.9 -1.3 +o.4 -1.7 -0.2 -0.7
( ) interpolated
*
20-day period only

Fisheries oceanography - 204 -
Table II. Bottom temperatures at Lurcher Lightship, 1961
Jan. (5.3) July 6.6
Feb. 2.5 Aug. 7.8
Mar. 1.7 Sept. 8.5
Apr. 1.8 Oct. 8.8
May 2.8 Nov. --
June Dec. 7.4
Average monthly bottom temperature variation from 1960-61
Jan. to June
July to Dec.
Jan. to Dec.
-0.6
-0.4 (3 months only)
-0.5
Average monthly bottom temperature deviation from 1950-59
( ) interpolated
* 20-day period only
No. 91
MONITORING OCEANOGRAPHIC CONDITIONS ON THE
SCOTIAN SHELF, HALIFAX SECTION, 1961
L. M. Lauzier
J. H. Hull
Four seasonal crossings of the Halifax section were
carried out in 1961 by Atlantic Oceanographic Group or in
co-operation with their field program. In general, the
conditions in 1961 were very similar to those observed in 1959.
The effect of intense winter cooling has been felt all year,
at least in the intermediate cold-water layer.
The conditions of the surface layer in February were
similar to those of 1959 as most of the temperatures in the
upper 50 metres were below 2.0°C and as low as -l.4°C. However,
in 1961, the extent of -l.0°C water was greater than in 1959.
These conditions were in contrast with those of 1960, when the
temperatures in the same layer varied between 0.5 and 5.0°C.
The horizontal salinity gradient in the surface layer was
steeper in 1960 than in 1961, suggesting a stronger southwesterly
movement during that year. On, and to the south of Emerald
Bank, the February bottom temperatures were slightly lower than
during the previous two years. In the Scotian Gulf, the ·
temperatures were somewhat higher than in 1960 but lower than
average. Along the edge of the Continental Shelf an intrusion
of warm water brought about a steep temperature gradient along
the bottom.

- 205 - Fisheries oceanography
From spring to autumn, a well-developed cold-water
layer, with minimum temperatures sometimes as low as 2 - 3°C
was the main feature of the waters over the Shelf in 1961. This
is the third year in succession that such conditions have
existed. In the early fifties, the intermediate cold-water
layer had a minimum temperature higher than usualo It was not
as well developed as it had been in the thirtieso Conditions
observed in the last few years are undoubtedly similar to those
observed during the thirties. The maximum temperature observed
in the deep waters of the Scotian Gulf from spring to autumn was
7.1°C, a temperature lower than averageo
During the summer cruise, in the middle of August, the
low temperatures and relatively high salinities near the coast
suggest upwelling along the coast., Unseasonably low temperatures
had been observed at Sambro Lightship in Augusto
The surface layer was much warmer in November 1961 than
at the same time in 1960.
No. 92
Lo Mo
BOTTOM TEMPEHATURES, SCOTIAN SHELF
AND BAY OF FUNDY AREA IN 1961
Lauzier
With temperatures in the Scotian Gulf being lower than
average, and a well-developed cold water layer dominating the
central sector of the Scotian Shelf, below-average temperatures
resulted on Emerald Bank all year. The temperatures were
generally lower in 1961 than in 1960. In the coastal area,
observations at Sambro Lightship by Naval Research Establishment
show that the 1961 bottom temperatures were generally lower than
those of the previous year by 0.7°C. The estimated 12-month
average temperature was at an all-time (since 1949) low of 1.7°C.
For the Bay of Fundy area, the Lurcher Lightship
temperatures have been reported in another summary as being
lower than in 1960o The maximum deviation (-2.4°C) from average
was observed in May. The estimated 12-month average temperature
at Lurcher was also at an all-time low (since 1951) of 5.5°C.
On the New Brunswick side of the Bay of Fundy, observations at
Prince 5 Station show that the bottom layer temperatures had·
generally decreased from 1960 to 1961 and that, during 9 months
of the year, they were lower than the long-term average. The
average deviation within the bottom layer was -o.44°C as compared
to -o.65°C in the surface layer. The lowest recorded
temperatures since 1950 at Station 5 occurred in 1959.
L. M. Lauzier

Fisheries oceanography - 206 ..
No. 93
WATERS ALONG THE SLOPES OF THE LAURENTIAN CHANNEL
During the early winter of 1960 and 1961, temperature
observations have been carried out from A.T. Cameron cruises in
the Gulf of Sto Lawrence and special emphasis was given to the
temperature structure along the slopes of the Laurentian Channel
north and east of the Magdalen Islands. The results are
presented in the accompanying figure.
These observations were made during a period of rapid
surface cooling. At the time of observations, the bottom
waters of the shallow parts of the sections had cooled to -l.0°C
north of the Magdalen Islands but not, however, to the east of
the Islands. The zone 0.0 - 2.0°C, in both years, seemed to be
shallower to the north of the Islands than to the east. The
thickness of the zone 2.0 - 4.0°C also seemed to vary along the
slopes, being reduced to the southeast. It is expected that the
features of the zone 0.0 - 2.0°C would change in time because of
the deepening of the 0.0°C isotherm with further cooling (until
the end of February, at least). However, the features of the
zone 2.0 - 4o0°C as shown at the time of observations were not
expected to change much in the course of the following few months
because they largely depend upon the behaviour of the warm deep
layer which has not yet shown any rapid changes.
Scanty observations were taken in the area north of
Magdalen Islands during the winters of 1956 and 1957. At that
time, the zone OoO - 2.0°C showed much variability (in depth and
thickness) as compared to the zone 2.0 - 4.0°C, which seemed to
be thinner and somewhat shallower than in later years. In
comparing the data from the Cabot Strait section and the section
just north of the Magdalen Islands, it would seem that the zone
2.0 - 4.0°C has a tendency to be thicker north of the Magdalen
Islands than in Cabot Strait. The assessment of the thickness
and depth of the two zones in 1961 was impaired by the great
depth variations of the isotherms along the slopes. It is
important to study the "micro-structure" of the temperature
distribution along the slopes of the Laurentian Channel, as the
observations were carried out on A.T. Cameron, in order to understand
the effect of environmental factors on the distribution of
marine animalso

- 207 -
Fisheries oceanography
AT C-16
A T C-32
AT C-17
A T C-32
JAN.23-24 1960
21 22 27
0,-~----~----~~~~
)•1.4
.
2
JAN.I7-18 1961
FEB.2 1960
II II II 22
)-0.9
JAN. 16-17 1961
f. ~0 , . ·~·
-1.0
50
100
150
200
,.5-
{
250
(4.8

Fisheries oceanography - 208 =
TEMPERATURE AND SALINITY CONDITIONS OF THE WATERS
IN THE NORTHERN SECTOR OF NORTHUMBERLAND STRAIT
During the last 14 years, weekly observations of
temperature and salinity were carried out off Richibucto, N.B.,
in the northern sector of Northumberland Strait from late
spring to early autumn. The purpose of this study, made in
conjunction with the lobster larvae investigation in the area,
was to monitor the seasonal and year-to-year variations of
oceanographic conditions of these waters, as well as the waters
in the southern Gulf of St. Lawrence during the summer. The
observations were made at three different levels, surface, 10
and 20 metreso
a) Average condition2_1248-1261
In a previous summary (A90.GQ Annual Report 1957-58)
10-year averages of temperature and salinity have been listed.
The accumulation of data since then warrants the presentation of
new long-term averagesu The 14-year averages are listed in the
accompanying table for every 2-week period from May to October
for the three levels of observation. In general, the 1958-1961
temperature averages from May to the middle of August were
slightly lower (-0.5°C) than those of 1948-1957, and slightly
higher (+0.3°C) from the middle of August to the end of October.
With the exception of one 15-day period, the 1958-1961 salinity
averages were slightly higher than those of 1948-1957.
Twice monthly averages of temperature
and salinity off Richibucto, N,B.
No. of
1948-1961 observa- Temperature Salinity%.
Month Date tions 0 m 10 m 20 m 0 m lQ_m 20 m
May 7 - 15 10 5.9 3c9 3·3 28.21 28.94 29.32
16 - 31 14 7.2 5.0 3o8 27.28 28.60 29.lt7
June 1 - 15 14- 10.1 7.9 6.6 27.88 28.4-8 28.85
16 - 30 26 13.1 9.4- 7.9 27o 52 28.29 28.60
July 1 - 15 28 15.2 12.1 8.3 27.30 27.84 28.47
16 - 31 32 17.5 13.3 8.9 27.37 27.86 28.56
Aug. 1 - 15 32 17.4 13.3 9.6 27. 35* 27.88* 28.59*
16 - 31 26 17.0 14-.9 10.7 2 7. 58* 2 7. 90* 28.67*
Sept. 1 - 15 25 16.1 15.3 12.7 27.73* 27.85* 28.30*
16 - 30 17 14.1 13.8 12.2 28.18* 28.27* 28.69*
Oct. 1 - 15 15 11.8 l1o7 10.9 28.5~* 28.55* 28. 76*
16 - 31 18 9.8 10.0 9.8 28.8 * 28.88* 28.91*
*Salinities August-October 1961 not included

) Conditions in 1961
- 209 - Fisheries oceanography
The surface temperatures, as observed from the
Pandalus II were lower than normal from the beginning of 1961
observations (May 24) until the second week of July. The
largest deviation at the surface occurred in May when the
temperatures were approximately 2.5°C lower than average.
During most of July and August, the surface temperatures were
oscillating around the average and during September and
October they were always higher than average. At 10 metres, the
temperatures were below average from May until the middle of
August, and above average until the end of October. Near the
bottom, at 20 metres, the observed temperatures were always
below average from May until the middle of October except on two
occasions in August. The vernal and aestival warming of the
intermediate and bottom waters was extremely slow in 1961 with
the result that by the middle of July 1961~ the temperatures
were as low as those of the beginning of June in average years.
Port Borden surface temperatures for May and June 1961 were also
abno,rmally lowo
The salinity data for 1961 are available for only the
first 11 weeks of operation. The surface salinities in May and
June were much below average, presumably resulting from late
thawing and clearing of ice and 'also late local freshets. This
low surface salinity resulted in a strong stratification. During
July the salinities were slightly below average at the surface
and above average on the bottom.
No. 95
L. M. Lauzier
J. H. Hull
LONG-TERM VARIATION OF WATER TEMPERATURES
The long-term variations of water temperatures in the
Bay of Fundy area and on the Scotian Shelf are best represented
by a combination of the three up-to-date curves shown in the
accompanying figure. These curves are 10-year moving averages
of surface water temperatures at St. Andrews, N.B., and of air
temperatures at Sable Island and Halifax, N.S. The forecast
value for 1953-1962 is represented in brackets. It shows a
continuation of the cooling trend.
At the present time, the cooling trend is of great
concern to the fisheries scientist and to the fishing industry
because of the environmental changes to which the fisheries are
subjected. Such changes are monitored and followed closely. The
waters of the Bay of Fundy area and of the Scotian Shelf vary at
unison. The waters of the Gulf of St. Lawrence seem to show some
local long-term variations. It is expected that, by this time
next year, a better knowledge of the Gulf of St. Lawrence longterm
variations will be presented, since analysis of Grande
Rivi~re temperature data, in comparison with Entry Island data
and others, is already underway.

OF
8.0
7.5
St. Andrews, NB
(water)
~
47
(.) I
oc
8.0
7.5
t:l:j
......
en
::r
(I)
li
......
(I)
en
0
Q
(I)
~
::s
0
O'Q
li
~
't:1
::r
c.::
46
45
Halifax,NS
(air)
Sable Island
(air)
7.0
46
45
7.0
I
1\)
j-J
0
t-'
•
:s:
•
t-'
~
,::::
t-1
1-'•
(l)
li
44
43
1880 1890 1900 1910 1920 1930 1940 1950 1960
Years
Water- temperatures at St. Andrews, N.B. (Centigrade) and air temperatures at Sable
Island, N.S., and Halifax, N.S. (Fahrenheit): 10-year· moving averages credited to the
middle of each period.
44

No. 96
- 211 - Fisheries oceanography
LONG-TERM WATER TEMPERATURE VARIATIONS
AND THE RESULTANT WIND ANOMALIES
The water temperature variations are compared with the
anomalies of resultant winds along the Canadian Atlantic coast
for the period 1945-1960 in order to correlate the long-term
temperature variations with the changes in atmospheric circulation
as measured by wind anomalies. Analysis of resultant
winds and their anomalies will be used in the interpretation
of drift-bottle recoveries.
Various arrangements of wind components and anomalies
are being tested for correlation.
No. 97
L. M. Lauzier
J. L. Leigh
LONG-TERM TEMPERATURE VArliATIONS
AND THE COD-HADDOCK RATIO IN COMMERCIAL CATCHES
The statistics show that cod and haddock are landed
from a very large portion of ICNAF Subarea 4 in variable
quantities. The optimum temperatures for cod and haddock are
known to be somewhat different, that for haddock temperature
being higher than that for cod. It is most probable that a
change in the physical environment, such as the average
temperature over a fishing bank~would have an influence on the
relative distribution of cod and haddock over this area. Such
variations would be reflected in the commercial catches if the
area considered is large enough and also if the economic factors
and the changes in the methods of fishing are relatively noninfluential.
The relationship between the long-term variations of
temperatures over the Scotian Shelf and the variations of the
ratio of cod catches to haddock catches has been used previously
on data up to 1955 (McLellan and Lauzier) in an attempt to
forecast the conditions for the next 20 years. At the time, a
10-year moving average of Sable Island air temperature was taken
as an index of water temperature variations. The Canadian and
United States landings in the whole of Subarea 4 were used to
measure the relative landings of cod and haddock.
Since then the relationship has been followed closely
from year to year and other arrangements of moving average
temperatures have been related to the cod-haddock ratio. A
7-year moving average has been chosen because of the closer
similarity between this new index and the actual trend of bottom

7-year moving average
air temperature: Sable Island
46
- 212 -
log C/H
0.1
0.2
0.3
o.4
0.5
0.6
0.7
0.8
0.9
1940 1950 1960
Years
Cod-haddock ratio in commercial catches, ICNAF Subarea 4 (~--~-x)
and index of t.emperature variations on· Scotian Shelf ~---~
log C/H
• 1917 - 1930
X 1931 1950
• 1951 - 1960
0.1~------~--------------~----------------T----------------.--
44.0 46.0 47.0
(7-year moving average
(air temperature: Sable Island
rielationship between cod-haddock ratio and index of temperature variations.

- 213 - Fisheries oceanography
water temperatures in the central Scotian Shelf during the
last 11 years.
The relationship between the cod-haddock ratio and the
temperature variations are shown in the accompanying figure, as
time series and also as a temperature--cod-haddock ratio
relationship. The similarities in highs and lows of the time
series are rather remarkable. The temperature--cod-haddock
ratio graph presents an unexpected picture. One curve would
represent the relationship between the two parameters but a
series of curves would be more appropriate showing a breakdown
in the relationship. This would indicate maybe that one or more
of the assumptions made previously are valid only for certain
periods such as between 1917 and 1930, 1931 and 1950, and
between 1951 and 1960.
Thi~ type of relationship might be useful for the
statistician and the biologist to study the catchability of the
two species and the effect of fishing on the stocks, under
different environments,
Before becoming the intended tool fo;:- forecasting future
trends of relative catches as based on the changes of the
environment, this relationship will have to be tested on more
discrete areas than the ICNAF Subarea 4 and on individual trawl
catches in a large variety of environmental and fishing conditions.
No. 98
EVAPORATION IN THl£ GULLi, OF ST. L.tiWRENCE
L. M. Lauzier
One of the important factors in the energy budget of
a body of water is evaporation. It could be determined directly,
computed from heat budget studies or, in an enclosed sea or a
lake, from water budget studies. During a study of the heat
budget of the waters of the Gulf of St. Lawrence, the heat lost
due to evaporation has been computed for a 24-month period.
From these values, the amount of evaporation of the waters of
the Gulf of St. Lawrence has been calculated. The meteorological
data used for the computations were representative of the coastal
areas. The amount of ice coverage during the winter months was
taken into consideration. The Gulf has been divided into two
sectors, a northern and a southern sector with the dividing line
being approximately 49° latitude. To the best of our knowledge,
no value of evaporation has been calculated as yet.
The amount of precipitation has been estimated for the
same period from the monthly weather maps supplied by the
Meteorological Service. The difference, Precipitation-Evaporation
has been calculated.

Fisheries oceanography - 214 -
The following table gives the average quarterly values
of precipitation and evaporation for two sectors of the Gulf of
St. Lawrence during the period June 1955 to June 1956.
Table evaporation and precipitation
in the Gulf of St. Lawrence
Northern Sector
Southern Sector
Period P(inches~ E(inches) P-E P~inches) E~inches) P-E
Jan.-Mar. Sol 6c4 1.7 10.4 3.1 7.1
April-June 7.1 1.4 5.7 8.5 2.6 5.9
July-Sept. 9.8 7.0 2.8 10.7 17.3 -6.6
Oct.-Dec. 8.8 12.9 -4.1 9.0 17.2 -8.2
Jan.-Dec. 33.8 27.7 +6.1 38.6 40.2 -1.5
These average values of 27.7 and 40o2 inches of
evaporation, 70.5 and 102 em respectively, are comparable to the
mean evaporation rate of approximately 75 em per year from the
Atlantic Ocean in the vicinity of latitude 48°N as reported by
MacGregor from WUst. Our results show that the northern sector
of the Gulf has some similarities with the high latitude regions
of the oceans where the precipitation exceeds the evaporation.
The southern sector has similarities with subtropical regions as
far as the relation, Precipitation-Evaporation is concerned.
The seasonal variations of P-E is also noticeable.
No. 99
L. M. Lauzier
PARTICIPATION TO ICNAF ENVIRONMENTAL WORKING PARTY
Following a preliminary meeting of the Working Party
in Moscow, USSh, in September 1960, the members were convened
to the formal meeting in Aberdeen, Scotland, on March 14, 1961,
under the chairmanship of Dr. C.E. Lucas of the Marine Laboratory,
Aberdeen, Scotland. The other members of the Working Party,
appointed by ICNAF, were: H. Graham, U.S.A.; F. Hermann,
Denmark; Gc Krefft, Germany; L.M. Lauzier, Canada; A.J. Lee,
U.K. ; J. J. Marty, USSR.
The Working Party had the responsibility of (1)
reviewing th2 various aspects of the environment, physical as
well as biological, as they affect the groundfish fisheries in
the ICNAF area from Greenland to Georges Bank, (2) making
proposals for an environmental research program to ICNAF, (3)
making proposal for an ICNAF "Environmental Symposium" in 1963.
A final meeting was held at Woods Hole in June 1961
when the report of the Environmental Working Party was presented

to ICNAF.
- 215 - Fisheries oceanography
The "Environmental Symposium" will be held in Halifax,
N.S., prior to the annual meeting of the Commission. The
symposium will be divided into eight topics and two Canadians
have been appointed conveners of a subject: Dr. W. Templeman
for "Effect of the biological environment on the distribution
of adult fish" and L.M. Lauzier for "Effect of long-term trends."
No. 100
LIBB.A.HY OF OCEANOGRAPHIC DATA
L. M. Lauzier
This investigation is the custodian of the library of
oceanographic data started in 1945. The library contains most
of the Canadian data gathered along the east coast and in the
eastern Arctic. A very large proportion of published foreign
data collected along our coasts is also on file~
The data cards, both hydrographic and BT, are filed
under a cruise file and a key file (degree latitude and
longitude). This investigation continues to maintain the
library of data. Every effort is made to keep it up to date
with data from both the Fisheries Research Board and that supplied
by other Canadian agencies. A stepped-up program in environmental
research within the Fisheries Research Board is resulting in a
noticeable increase in the amount of data being made available for
filing. Continued increases will therefore result in a more
comprehensive coverage of the oceanographic aspects of both our
coastal and adjacent waterse
Use of the library is made by the various investigations
at the Biological Station and also by the Division of Oceanographic
Research of Department of Mines and Technical Surveys, the
Atlantic Oceanographic Group and the Working Party on Information
Services for Defence in Halifax, N.S. The library played a vital
role in supplying the Canadian data to the new Canadian
Oceanographic Data Centre of the Division of Oceanographic
Research. The facilities of the library are used to prepare the
annual compilation of Fisheries Research Board observations in
the ICNAF area.
J. H. Hull

SMELT SUMMARY
Number
Page
The smelt fishery of the Mira11.ichi, 1960-61 101 217 - 218

No. 101
- 217 Sae1t
THE SMELT FISHERY OF THE MIRAMICHI, 1960-61
The Miramichi smelt fishery in 1960-61 was reported
to be less than 1~ of what it was a few years ago and consequently
considered to be "practically a failure".
Table I shows that the total catch actually was less
than at any time during the last 15 seasons but so were the
numbers of nets licensedo Quite a number of fishermen experienced
a very poor season but many had good and even excellent seasons.
The average catch per net licensed in 1960-61 was 882 lb compared
to the 15~year average of 608 lbG Log-book records kept
by 10 smelt fishermen also show that though total landings were
at a very low level the catch per net"·day fished was about
average, that is, 9.~ lb compared to the 9o2 for a 10-year
average.
Table Io Statistics of the Miramichi smelt fishery, 1946-61.
Season
Total
catch
Value
per cwt
Catch
Noo nets per net
licensed per season
AVo catch
per-net-day
fished
cwt
$
No
lb
lb
1946-47
1947-48
1948-49
1949-50
1950-51
1951-52
1952-53
1953-54
1954-55
1955-56
1956-57
1957-58
1958-59
1959-60
1960-61
11,417
23,43?
20,133
11,775
21:1780
~,535
16,235
11,831
20,579
11,815
5,024
8,722
6,709
4,677
lt,569
19o0
20.3
11.0
15ol
13o7
21o6
19.6
12.8
12o0
13.0
13.5
llo7
15o9
12o0
9o0
2,1-t-32 469
3,066 ?64
3,266 616
3,085 382
2~811 775
2,218
g~
2,482
2,139 553
2,027 1,015
1,513 781
1,5~3
~~
1,3 0
1:1288 ~21
1,073 36
518 882
Average
12,482
15uO
2,054 608
··· The average price of 9 cents per pound during the
1960-61 season was the lowest paid in 15 years and was 6 cents
below the average for 1946-61o The price did nothing to either

Sllelt - 218
encourage fishing or make up for the poor catches obtained by
some of the fishermen.
Any major change in the abundance of the stock should
be detectable in the size of the spawning run, so a survey of the
1961 spawning was conducted by the Fisheries Protection Officers
of the Miramichi and by the author during two short trips to the
area. The information obtained ~bowed that the spawning stock
was not drastically reducedo However, because of the tremendous
freshet and long period of high water during the spawning
season (greater than at any time during the last 20 years) the
success of the 1961 spawning may well have been far below
average.
The fact that no drastic reduction was found in the
1961 spawning stock shows that the lack of fish in some parts
of the fishery was a m•tter of distribution rather than actual
scarcity of fish.
Many fishermen believe that the extent of ice cover
off the Miramichi influences the time of arrival and concentration
of the smelt on the fishing groundso When the ice
extends well offshore? the smelt have protection from the open
storm-tossed waters of the Gulf of Sto Lawrence shallows without
being in the ice~covered Miramichi Bay where the fishery
is located. During the winter of 1960-61 the ice in the Gulf
of St. Lawrence formed earlier than usual, was thicker, more
extensive! and lasted longer into MaYo In fact, it would have
been poss ble to cross on the ice from New Brunswick to Newfoundland
during 8 weeks of the 1960-61 wintero Because of
this unusual ice-cover the smelt may well have remained dispersed
outside the Miramichi much later than usuali entering
in quantity only in time to make the annual spawning run which
was later than usual as the spring "break-up" was later than at
any time during the last 130 years.
Ro A. McKenzie

MATHEMATICAL STATISTICS SUMMARIES
Estimation of mortality rates of fish
populations
On the analysis of lobster populations
Sampling the deck catch of a research
vessel
Sampling the commercial landings of
groundfish
Number
102
103
lo4
105'
Page
219 - 221
221 - 224
224 - 225'
225 - 22?

No. 102
- 219 - Mathematical statistics
ESTIMATION OF MORTALITY RATES OF FISH POPULATIONS
Many of the fisheries research organiza tiona studyi-ng
commercial fisheries collect catch and effort information. It
is the expectation that these data may be used to follow population
fluctuations, to estimate the total mortality rate and to
separate the total mortality rate into its component natural
and fishing mortality rates. It is perhaps the latter task ·that
has inspired biologists and international fisheries organizations
such as ICNAF and FAO to press for the collection of more and
more detailed effort data.
Concurrently with the refinements of the source data,
methods of nandling these data have been developing. In the
last Annual Report we gave an account of a new estimation
procedure which increased the accuracy of the estimation of
mortality rates by about 50~ (in terms of the variance of the
estimates). However, application of the new method w determine
offshol"e haddock population in the northwest Atlantic resulted
in estimates which still have such a large error variance as to
be practically useless.
Since the first application of the new method (linear
formula) to offshore haddock fisheries, the U.S. Fish and
Wildlife Service had made available seasonal catch per effort
figure$ for Georges Bank which were not previously available.
This has made it possible to take the seasonal variations into
account in the analysis of a haddock fishery similar tothe
Canadian fishery.
In the accompanying figure we show the total··(instantaneous)
mortality rate from 1931-1959 for Georges Bank haddock
by quarter years (2, 3i, etc. year-old fish). Due to the
regularity in time of spawning the different quarters correspond
to biological flseasons". To the observed points we·have fitted
a parabola representing the course of the average total mortality
rate through the haddock's life span in the fishery.
It is evident from the graph first of all that the
variability between seasons is rather large, hence that it must
be taken into account in the analysis. Secondly, from,the
fitted parabola representing the average mortality, we may
conclude either that the mortality increases or the catchability
decreases with age. The increase in the apparent mortality
rate may be represented by the expression:
z = .'+0 + .0476 {]. + 2(j - 3~
where j stands for age. This means, for example, that the
total apparent mortality rate at age 3 is 0.1+; but at age 6 is
0.73·

Mathematical statistics
210
190
- 220 -
Fig. 1. Georges Bank Haddock
1931-52, 1954-59. Sums
of the logarithms of the
catches per effort
plotted against age.
180
170
160
150
140
130
~
..-1
- 120
Ct-1
..._, 0
"
~ 110
r-1
~1..-t
100
90
80
70
60
3rd
yr.
5th
yr.
7th
yr.
9th lOth
yr. yr.

- 22~ - Mathematical statistics
The pertinent formulae for estimating normal catchability
coefficients and annual mortality rates together with
the calculations are given in Manuscript Report Nco 714 of the
Fisheries Res~arch Boardo Here it is enough to say that the
detailed analysis did not result in any significanf improvements
in the estimateso Indeed no correlation between tne estimated
total mortality rate and effort was evidento
While the lack of correlation may partly reflect the
error inherent in gross fisheries statistics, we suspect that
the factors underlying the variability are of more basic
importanceo In fact, the expectation of correlations between
simple measures of apparent change in abundance and effort arises
from the commonly made assumption that the theory of random search
is an appropriate way to describe the activity of fishing vessels
and the populations they are fishingo However, the regular shortterm
variations exhibited by fisheries data such as found· in
haddock and in our analysis of lobster data clearly support the
common sense conclusion that changes in catch are sensitive to
secular changes in the distributions of the fleet and the fish
as they are to overall changes in abundanceo As a first step in
determining the effects of distributions on catch, •e are currently
analysing resgarcb vessel data which give information on stock
distributions, as well as the detailed log records of catch per
unit effort of the fleets exploiting these stockso It is hoped
to arrive'ata measure of species association and distribution
which may describe the stocks and fishing more adequately and
result in useful predictions of catch changes.
No. 103
ON THE ANALYSIS OF LOBSTER POPULATIONS
J. E. Paloheiao
The lobster investigation has beenstudying Fourchu,
N.S., Gabarus, NoSo 9 Port Maitland, N.S., Mj;minegash, P.E.I.,
and Tignish, PoE.!., commercial fisheries for a number of years.
In these ports statistics have been collected on catch and ~ts
size composition, on numbers of trap hauls and on temperatures.
Each year such statistics have been collected, an independent
tagging experiment has also been made toward the beginning of
the season in each area by tagging and releasing about 1,000
lobsterso
These statistics have been used to determine the
numbers of legal-size lobsters on the ground at the beginning
and at 1 the end of the season, the rate cf exploitation, ·and
the relationship between temperatur• and catcbabil1ty (probability
of capture)o
From catch per effort figures corrected for the
accumulated removal of lobsters by the fishery, we have derived

Mathematical statistics - 222 ~
a relationship between the temperature and probability of
captures (catchability coefficient) qo This relationship
may be based on either catch statistics or on tag returnso
In Table ·I, we have shown the relationships based on catch
statistics for four study areas (the Miminegash fishery has
been omitted because of more or less constant temperature
during the season)o
Table I. Relationship between the catchability coefficient,
q~ and temperature C~o
Area
Fourchu Gabarus---- Port Maitland Tignish
In general one might expect that the relationship
between the catchability coefficient and temperature should be
the same for all areas" From Table I it is obvious that this is
not the caseo A more detailed analysis suggests that these
discrepancies are attributable to non random distributions of
gear and lobsters as well as to the effects of density which
cannot be taken into account in the form of the catch equation
used by most fisheries workers and applied hereo Ways of overcoming
this difficulty are being further studied by-generating
stochastic-models which mere closely approximate the conditions
of the fisheryo
The population sizes may be determined using either
catch statistics along with records of tagged lobsters released
and caught or catch statistics~ number of trap hauls and temperature
datao Both methods result in somewhat biassed estimates
because of the lack of randomness in the distribution of lobsters
on the bottomo ·
To summarize some of the results we have given in
Table II figures for the average catch (lb~, the average population
size-of legal-size lobsters in numbers, rate of exploitation,
and corresponding number of trap hauls as well as the approximate
size of each study areao Production in each area is indicated
by the catch per square mileo Population sizes are all based en
tag returnso
Comparison of the productivity of the study areas in
Table II suggests that the productivity is highest in these areas
(Gabarus and Port Maitland) where the fishing is lightest and
lowest (Fourchu 9 Miminegash, Tignish) where the fishing is
heaviesto When this observation is coupled with earlier studies
(cf. Summary Report Nco 3 in 1959-60 Annual Report), one is tempted

- 223 - Mathematical statistics
Table II. Summary statistics describing the fishery and lobster
pbpulation in the study areas.
Fourchu Gabarus Miminegash Port Maitl,and Tignish
Year 195'6-60 195"7-60. 1946-5'8 1947-r;'l. 23-5'6>-· 195'1-5'6, 58
Average
landings (lb)l6a,626 221,130 183,881
Average population
size
(nulllber of
lobsters) 168,840 35'5,000 306,346
Rate of
.exploitation 74% 65'% 72%*
No. of trap
hauls 144,003 255,5'9? 280,428
Size of the
area (sq. .
nautical mile) 20.8
21.4
- 341,85'8
609,016
312,672
32.5
Production (lb)
per sq. mf~e · . 7,819 10,333 7,183 10,519
* based only on the first four weeks of the season.
475,837
1,189, 714
68%
1,067, 5'69
55'.0
8,651
to conclude that the latter lobster grounds are heavily overfished
and that to correct the situation one should increa~& the minimum
legal-size limit. However, without further information on sublegll
lobs-ters ,on the react'lcn of different sized lobster-s to
traps; an:d- on the basic productivity of the grounds (availability
of food, amount of cover, etc.) such conclusion from the above
data would be premature.
Overfishing can take place in two ways; on the one hand
by catching the lobster too soon beyond the minimum legal-size
limit so that fishing harvests too little of the potential growth
and on the Qther hand by saturating the ground with gear so that
different units of gear interfere with each other. The latter
reason perhaps explains the very low catchability- -coefficient
in the Tignish area. Thus it 1;1pp1Jars- th~t- r~duct-ien---1-n- numbers
of tra~·hauls in heavily fished areas such as Tignish would not
decrease the total take by the fishery, but would increase the
economic return to those engaged in fishing.
In general we believe that the analysis of the commercial.
lobster statistics and tagging e:x}>eriments has greatly
increased our knowledge of the lobster stocks. However, further
collection of similar statistics is not likely to bring anything
new to light unless the collection is made to include additional

Mathematical statistics - 224 -
information on temperature and distribution of fishing gear and
lobsters on the bottomo
Moreover, it appears that the information on catchabilities
and on population sizes has by itself only a limited
use unless it can be contrasted with more information on lobsters
of sublegal sizes as well as on the potential productivity ·or
the study areaso
A more detailed account of these studies has been
prepared for publicationo
No. 104
SAMPLING THE DECK CATCH OF A RESEARCH VESSEL
J. E. Paloheimo
It is frequently ccnsidered advantageous to sample
the catch of large research vessels for estimates of total count
of particular species, by counting the numbers contained in a
given proportion of the samp,le units. A preliminary assessment
of the possibil1ty of' obtaintng estimates with specified accuracy
was reported last year (Summary Nco 103, 1960-61 Annual Report)
on the basis of trials carried out during a special cruise of
the A. T. Cameron. Standard ·:tatistical methods could not be
applied because the distribution of counts in the basket-sample
units varied in irregular fa:·l Lion. The further analysis
summarized here indicates tl , · unless special precautions are
taken, a high proportion of tr1e total catch must be counted to
give acceptable accuracy.
In our study the nature of the irregular statistical
distribution of the average count per basket could theoretically
be determined for any given level of sampling by complete
enumeration, since the universe of basket counts was known.
However, this is a practical impcssibility for large or even
moderate sized catcheso For ~xample there are(3~)~1.4 x 107
possible 8-basket samples in a catch of 33 basketso We had
therefore to resort to Monte Carlo methods and sample for the
statistical distribution. Setting the limits of acceptable
accuracy of the estimate of avera~e count as ± 10% of the true
average in 90% of cases at the 90% probability level, we have
classed estimates of the average which fall outside the 10%
limits as failures, and the others as successes. At any given
level of sampling the ratio of failures to total tries was
calculated and its 90% limits determined from binomial tables.
When acceptable accuracy was obtained with a few trials the
90% limits were established with 90% probability by increasing
the number of trials at that sampling level to the number
required by the tables.

- 225 - Mathematical statistics
The test ·was applied to a nwqber of catches. It was
found that when, as was usual, the length compositions of h$ddock
in the basket-sample units showed significant departure from
random assortment, estimates of total count were not likely to
be within the acceptable range unless 80% or more of the sample
units was counted. Stratification of the sampling units by
average size of fish in them seemed likely to reduce the required
count to about 55 or 60%. Procedures for randomizing the assortment
of fish sizes by mixing the basket units reduced the
required count to about 50% of the totalo ·
The manual labour of mixing added to the initial deck
handling timeQ However, it made sampling possibleo For at
least large catches this could result in appreciable savings
in total time required to make observations, thus saving valuable
ship operating time.
No. 105
SAMPLING THE COMMERCIAL LANDINGS OF GROUNDFISH
J. E. ·Paloheimo
L. M. Dickie
The data for many of the groundfish population studies
are derived from sampling of the commercial fish landings. For
these studies it is important to knew how good is the existing
sampling program and how the sampling could be improved. During
the past summer we began a study of the groundfish sampling
program to determine the accuracy of estimation of length and
age compositions of landings and of the resulting growth curve
of fish caughto The preliminary results are reported here.
A usual procedure in sampling the groundfish landings
in the Maritime Provinces is to sample about 200 haddock and
about 300 cod from landings of a vessel which has preferably
been fishing exclusively only one of the major fish stocks.
The fish are taken from market categories more or less in the
same proportion as they are represented in the total landings.
Exact proportionality factors are worked out later and the
measurements for categories are then weighted accordingly.
Each fish sampled is measured for length and from about every
fifth ~ish an otolith (ear bone) is taken to determine its age.
The age sampling is often stratified by length to obtain·a
better representation of less common length groups. On account
of the great number of partly separate fish stocks, rather ·
limited number of' samples are taken from each fish stock in each
biological season of 3-months duration, usually no more than a
half of dozeno From the limited number of samples the length
and age composition estimates of landings from major stocks are
compi1~d for each year and sometimes for ea·ch season.
To arrive at the seasonal age or length compositibn
s.amples of average weights of fish in market categories, the

Mathematical stati.stics - 226 ~
proportions of the market categories in the total as well as
the individual lengths and ages are sampled. Attempts to
construct a propagation of the error model to show the
contribution of each of these factors to the overall sampling
error have so far failed and the problem needs further study.
However, in the course of the analysis it became evident that
in using seasonal weighting factors rather than weighting
factors from the individual landings one runs a risk of
biasing the result. At present we do not know whether the
bias is important in practice since seasonal weighting factors
derived from all commercial landings from an area are likely
to constitute a more reliable sample of the stock than do the
small number of sampled landings.
In measuring the error in the present lengths and
age composition it became obvious that the within sample ·
variance~ a small component with the between sample variance
(the within sample variance was calculated using binomial
probabilities)" To equalize the between and within sample
val'iance a sample size of less than 50 fish instead of the
present 200 or 300 fish would be neededo However, the
practical difficulties of securing enough random samples with
small numbers have indicated that it may be wise to continue
with the present sample size. However it might be advantageous
to decrease the number of fish measured in each sample and to
take more than one sample from each market category of the
same catch.
In measuring the error in the estimated mean length
of haddock in samples of 200 fish each a standard deviation of
2.4 em was obtained. The standard deviation of the fraction
"p" of a haddock age group from the total measured was found
to follow the formula
•
This equation describes the relationship between the sampling
error (u) and the relative strength of the age and in Table I
has been used to calculate the dependence of the sampling error
on the number of samples.
Table I. The 95% limits for the age frequency expressed as a
fraction from the total at different levels of
sampling.
No. of samples
Age frequency (p)
200 fish each ___&2 ~ ~ .20 ~
1 :t .08 t .13 ± .17 ± .20 ± .25
5 ± .04 ± .06 t .07 ± .09 ± .10
10 ± .02 ± .04 ± .05 ± .06 ± .07

- 227 - Mathematical statistics
The impression one gets from Table I is that the error
limits are rather widee This appears to be always due to one
or two atypical samples, ieeo, samples which are quite different
from the rest of the samples for the same quarter and area. This
apparent heterogeneity has not ~bviously been eliminated by our
division of fishing areas into smaller geographical units.
Since our present area bre~kdown is perhaps as refined
as we can make it in practice, there does not seem to be any
possibility of increasing the accuracy of our sampling '
drastically. This means among other things that in order to
estimate such population parameters as the mortality rates we
must have some a priori biological information about the·form
the mortality curve might take to compensate for statistical
inaccuraciese
An important statistic derived from our sampling for
lengths and ages is the growth curveg Several methods have
been worked out to replace statistically unacceptable procedures
of fitting von Bertalanffy growth curves used currently by
fisheries scientists. The methods lead to estimates of error
limits for the parameters of the von Bertalanffy growth curve,
k (coefficient of anabolism in the body) and L~maximum length
of fish). A sample calculation.' for Western Bank haddock (1956
and 1957, I and II quarters) gave the following values: k = .88
with limits .81 to .94 and L~= 112 em with limits 98 em to 179
em.
An interesting observation emerging from the calculations
was a strong statistical correlation between the estimates
of k and L oo • This correlation has been found previously by
a number of biologists who have attached a biological meaning
to it. However, it se~ms to be only a statistical property due
to the estimation procedure used.
J. E. Paloheimo
from original manuscript by
We Knight