Work Package 2 - Department of the Environment

STRANGFORD LOUGH ECOLOGICAL CHANGE INVESTIGATION
QUEEN’S UNIVERSITY BELFAST
Work Package 2 – The current status of
Strangford Modiolus. KA 2.1: Diving Survey
2003
Dr D Roberts, School of Biology and Biochemistry, Queen’s University,
Belfast (Principal Investigator, SLECI)
Queen’s University Belfast
INTERIM REPORT: DECEMBER 2003

Executive Summary
Strangford Lough is currently on the UK list for designation as a Special Area
of Conservation (SAC) under the EC Habitats Directive (92/43/EEC). A major
feature for this candidacy is the sublittoral Modiolus modiolus biogenic reefs.
Government Departments/Agencies and non-government organisations
(NGOs) have expressed concern about the state of these reefs (EHS, 2002).
The Strangford Lough Ecological Change Investigation (SLECI),
commissioned by Environment & Heritage Service, aims to identify the current
conservation status of the Lough and any factors which may have contributed
to change. This investigation involves assessing possible current/historical
impacts of fishing or aquaculture, boating, change in climate, pollution,
dredging and shore works, algal blooms, diseases and parasites, and alien
species on the ecology of the Lough.
All biological field-work as planned in the original tender has been completed.
A total of 86 dive sites have been surveyed, some with repeat dives. Eighteen
intertidal sites have been surveyed. In both sets of surveys differences have
been noted between the present and earlier surveys. Analysis of biological
samples is nearly complete and data analysis, including analysis of over 30
hours of video records, has started.
The investigation is scheduled to be completed by December 2003 and will
report in full at the end of February 2004. However, the terms of the contract
allow for publication of parts of the investigation as they are completed. This is
a position report from work package 2 which is to investigate the current
extent and condition of the Modiolus communities in the Lough. This involved
a comprehensive diving survey undertaken in July and August and additional
dive surveys in October this year.
Detailed analysis of the underwater video footage and quadrat samples is not
yet complete, but the important issue is that this part of the study already
provides evidence of the extent of change in the Modiolus communities which
supports earlier studies. The Biogenic Modiolus reef feature in Strangford
Lough is no longer in ‘Favourable Conservation Status’ as compared to the
mid 1980’s and urgent management action to protect the few remaining
Modiolus beds within Strangford Lough should be considered by the
competent authorities.
SLECI INTERIM REPORT: DECEMBER 2003 2

Conclusions
1. The present study demonstrates that Modiolus reefs are no longer in
‘Favorable Conservation Status’ (The condition in which the habitat or
species is capable of sustaining itself on a long-term basis [Anon,
1997]) in Strangford Lough.
2. There was a 3.7km 2 reduction in clumped Modiolus communities
between 1993 and 2000.
3. Comparison of the current with earlier diving surveys confirms this
decline in Modiolus communities and suggests it is continuing.
4. There is no evidence to suggest recovery of Modiolus communities in
Strangford Lough has been taking place since the conservation
measures, involving legislation to manage fishing activity, were
introduced in 1993 to protect them.
5. There is therefore an urgency to protect remaining Modiolus
communities in Strangford Lough.
6. More detailed mapping, to determine the precise extent and condition
of the Modiolus communities using techniques developed by SLECI
and elsewhere are needed after the final SLECI report is completed.
7. The use of mobile bottom fishing gear poses the most immediate threat
to the few remaining clumped Modiolus communities within the
confines of Strangford Lough cSAC. Notwithstanding that Modiolus
recruitment is still occurring in Strangford Lough, the continued use of
mobile bottom fishing gear is likely to hinder natural recovery.
Fishermen trying to develop alternative, sustainable practices should
therefore be encouraged.
8. To build on the facts that Modiolus populations are similar in structure
to samples taken in the 1970s and recruitment appears to be still
occurring, a programme for the restoration of Modiolus biogenic reefs
in Strangford Lough should be considered; this should be underpinned
using state-of-the-art techniques to monitor physiological and shell
indicators of stress in Modiolus to ensure success.
SLECI INTERIM REPORT: DECEMBER 2003 3

Introduction
Modiolus modiolus communities form biogenic (i.e. produced by the actions
of living organisms) reefs that are a major selection feature of interest for the
Strangford Lough SAC (SAC Annex 1 selection feature ‘Reefs’). These beds
have been documented in the Lough since the mid 1800’s (Dickie,1857). In
the 1970s the Modiolus beds were known to be extensive (Erwin, 1978) and ‘
the bed situated amongst the numerous small islands off Killyleagh at depths
of 6 to 9 fathoms which were sampled regularly during this investigation,
appears to be well over one square mile in extent’ (Seed & Brown, 1977).
The full extent of the beds was not reported in detail until the early 1990s by
which time certain areas, particularly those occupied by the M. modiolus/
Chlamys varia community [JNCC biotope classification SCR.ModCvar.], were
heavily impacted by trawling for queen scallops, (Service & Magorrian, 1997).
It is now well established that trawling and dredging can damage biogenic
reefs, seabed communities and emergent epifauna (see for example: Watling
& Norse, 1998; Cranfield et al., 2003). As a result of recommendations by the
then Department of Agriculture for Northern Ireland (DANI now Department of
Agriculture and Rural Development [DARD]), a number of legislative
measures were introduced in 1993 to manage fishing activity (Service &
Magorrian, 1997).
The most recent broadscale acoustic survey, prior to SLECI, reported a
3.7km 2 reduction in area of clumped Modiolus between 1993 and 2000
(Mitchell et al. 2002). A repeat acoustic survey was conducted in 2003 and
will, following analysis and ground-truthing, be reported at a later date as part
of the present investigation.
One of the main aims of the current survey is to ascertain the current extent
and condition of Modiolus reefs as compared to diving surveys conducted by
the Ulster Museum during the 1970’s and 80’s.
Strangford Lough can be divided into two main basins north and south of Long
Sheelah (Appendix 1). The water in the southern basin mixes quite freely with
the Irish Sea, whilst the water in the northern basin is retained within the lough
for longer periods (Boyd, 1973).
Modiolus beds in the North Basin are characterised by Modiolus modiolus
co-dominant with Chlamys varia with abundant Queen scallops (Aequipecten
opercularis) and occur between 10m and 35m depth. This community was
described as a distinct biotope in the 1996 JNCC biotope classification with
coding SCR.ModCvar. The biotope is only known within Strangford Lough
and possibly Loch Creran in SW Scotland. It may represent a fine balance of
climatic conditions between suitability for Modiolus modiolus which has a
predominantly cold-water distribution and Chlamys varia which has a
SLECI INTERIM REPORT: DECEMBER 2003 4

predominantly temperate-water distribution. The large numbers of queen
scallops (queenies), were formerly the basis of a commercial fishery in
Strangford Lough.
Modiolus beds in the South Basin have few Chlamys or Aequipecten but
more hydroids and brittlestars (biotope code: SCR.ModHAs) and are less
diverse than the Modiolus/Chlamys biotope. They have few Chlamys or
Aequipecten and so have not been subjected to trawling for queenies,
although they are in the dredging zone for King scallops. Beds like these are
also found on the coast of the Ards peninsula and other places outside
Strangford Lough.
Both types of reefs are a major feature of the Lough justifying its status as a
candidate Special Area of Conservation (cSAC) and as a Marine Nature
Reserve.
In their 1997 paper, Service and Magorrian indicated that management of
fishing activity in the Lough, together with the establishment of Strangford
Lough as a Marine nature reserve, would allow future assessment of recovery
of areas formerly impacted by mobile bottom gear.
This preliminary report provides the most recent information on the current
extent and condition of the Modiolus communities in the Lough based on a
comprehensive diving survey undertaken in July and August and additional
dive surveys in October this year. The findings presented here will be
integrated in the final report with detailed RoxAnn surveys of the Lough
undertaken this year and with other surveys carried out since the mid 1990s
by DARD.
Methods
Dive Survey
Divers working in pairs carried out direct observations and sampling of the
seabed. A total of 86 dive sites (Appendix 2) were visited during July August
and October 2003. Some of these were chosen to be as close as possible to
the Modiolus dominated sites found in the earlier Northern Ireland Sublittoral
Survey/Ulster Museum between 1975 and 1985. Other dive sites were in
different habitats and were chosen to investigate possible changes in these
other habitats.
Modiolus habitat condition was assessed at a number of sites using 100m
transect lines marked at 1m intervals using the method reported by Brown
(1989). In the present study, observations were supported by underwater
video footage shot on 3-chip digital video cameras in underwater housings.
Processing of samples and video is still in progress.
Population and community studies
Modiolus modiolus was collected from three areas identified as having
relatively dense areas of Modiolus biotopes:
SLECI INTERIM REPORT: DECEMBER 2003 5

1. North of the Long Sheelah,
2. The raised area to the west of Round Island
3. The area known as the Black Rock beds.
In these areas, 0.25m 2 quadrats were taken at random points along a 100m
transect laid on the seabed. The samples were transferred into mesh onion
bags, attached to a lifting bag and raised to the surface boat where they were
placed in buckets of seawater. In the laboratory the samples were washed
through a 1mm sieve and live Modiolus were removed from the sample. Shell
length, height and width were measured to the nearest 0.1mm using callipers.
The Modiolus were then placed in holding tanks for subsequent experiments.
The remainder of the quadrat samples were preserved in 70% alcohol for
further community analysis.
SLECI INTERIM REPORT: DECEMBER 2003 6

Results
Dive survey
Modiolus beds in Strangford Lough as reported by Ulster Museum divers
between 1975 and 1985 are shown in Appendix 1. The beds were
widespread below the 10 m contour and largely undisturbed during this
period; beds were characterised by biotope SCR.ModCvar. (Figures 1a,b) in
the north basin, where the majority of dive sites had Modiolus, and biotope
SCR.ModHAs. (Figutre 1c,d) in the south basin.
Current situation
In the present study (2003) intact, clumped Modiolus beds were located at
only six out of a total of 44 field-sampling sites in a small area in the North
Basin and eight out of a total of 41 sites in four widely spaced areas in the
South Basin (Appendix 2).
North Basin [SCR.ModCvar]
In the North Basin the Modiolus beds appear to be very much reduced in
extent. Only six field-sampling sites in a small area in the North Basin are the
classic Modiolus with Chlamys community or biotope (SCR.ModCvar)
(Figures 1a,b). These are located at the side of this basin and these may no
longer be in pristine condition (dive sites 11, 36, 37 48, 63 and 77 in Appendix
2) as indicated by the decline in some key species of sponges and
echinoderms. By contrast, the majority of sites in the north basin surveyed by
divers between 1975 and 1985, had clumped Modiolus communities.
At the centre of the North Basin, which was formerly the main area for the
classic Modiolus with Chlamys biotope but was also zoned for trawling of
queenies, no clumped Modiolus remain at any site visited; this area now
has extensive areas of dead shell with occasional live Modiolus individuals.
(Figures 1e,f). Very few queen scallops were observed at any site within the
North Basin.
South Basin [SCR.ModHAs]
Modiolus beds (biotope SCR.ModHAs) were historically present in several
areas in the south basin, East of Black Rock, East of Taggart Island and at
various places between the Limestone Rock and the Long Sheelah. Three of
these areas were surveyed during the present study.
Black Rock beds
They are currently mostly intact, though areas adjacent to them are in poor
condition, with many Modiolus almost completely buried in muddy sediment
which appears to be recently accumulated.
Area to west of Round Island
This area had not been surveyed previously by diving. It was found to have
clumped Modiolus beds from 10m to 30m depth. The beds were more
disrupted in deeper water but otherwise showed little sign of disturbance.
SLECI INTERIM REPORT: DECEMBER 2003 7

Channel East of Selk Rock, Taggart Island
The bottom here was reported to have a dense bed of Modiolus modiolus in
1976 by Ulster Museum divers. It now consists of mostly dead shells, with a
scattering of live Modiolus. At this site areas of dense dead shell alternated
with bare mud.
SLECI INTERIM REPORT: DECEMBER 2003 8

a) Modiolus clump in intact bed -
Modiolus/Chlamys biotope, Ophiothrix
brittlestars
c) Modiolus clump from south basin,
with hydroids and Antedon
e) Area of dead Modiolus shell - main channel,
North basin
Figure 1. Stills images from video footage
b) Modiolus/Chlamys clump, Chlamys varia
feeding and showing mantles
d) Modiolus showing “clean” appearance of
south basin mussels
f) Area of mud with shell, adjacent to Fig. 2e.
SLECI INTERIM REPORT: DECEMBER 2003 9

Preliminary Population studies
Data from the current population census were grouped by area and sorted
into 5mm size classes. Size frequency histograms were constructed for these
three areas and compared to data taken by Brown between 1973 and 1976
(Brown, 1976) (Figure 2).
20 . 0
18 . 0
16 . 0
14 . 0 n = 1006
25.0
20.0
n = 54
%
12 . 0
10 . 0
8.0
15.0 %
%
6.0
4.0
2.0
0.0
30 .0
25 .0
20 .0
15 .0
10 .0
5.0
0.0
0 to 5
0-4.9
5 to 10
5.0-9.9
a) South Basin (Brown 1974)
10 to 15
15 to 20
20 to 25
25 to 30
30 to 35
35 to 40
40 to 45
45 to 50
50 to 55
55 to 60
60 to 65
Size Class (mm)
c) Area B South Basin
(Present study 2003)
n = 136
10.0-14.9
15.0-19.9
20.0-24.9
25.0-29.9
30.0-34.9
35.0-39.9
40.0-44.9
45.0-49.9
50.0-54.9
55.0-59.9
65 to 70
60.0-64.9
70 to 75
65.0-69.9
Size Category (mm)
75 to 80
70.0-74.9
80 to 85
75.0-79.9
85 to 90
80.0-84.9
90 to 95
85.0-89.9
95 to 100
90.0-94.9
100 to 105
95.0-99.9
105 to 110
100.0-1 04.9
110 to 115
105.0-1 09.9
110.0-1 14.9
115.0-1 19.9
SLECI INTERIM REPORT: DECEMBER 2003 10
30.0
10.0
5.0
0.0
30.0
25.0
20.0
15.0
10.0
0-4.9
5. 0
0. 0
0-4.9
5.0-9.9
5. 0- 9. 9
10.0-1 4.9
10.0-14.9
15.0-1 9.9
15.0-19.9
20.0-2 4.9
20.0-24.9
25.0-2 9.9
25.0-29.9
30.0-3 4.9
30.0-34.9
35.0-3 9.9
35.0-39.9
40.0-4 4.9
40.0-44.9
45.0-4 9.9
45.0-49.9
50.0-5 4.9
55.0-5 9.9
60.0-6 4.9
65.0-6 9.9
Size Category (mm)
50.0-54.9
55.0-59.9
60.0-64.9
65.0-69.9
Size Category (mm)
Figure 2. Comparison of the population profiles of Modiolus modiolus
(% size frequencies) in Strangford Lough for 1974,and 2003 (Areas A, B
& C).
Earlier samples (Figure 2a) showed a skewed population modality
characteristic of populations dominated by older individuals and typical of
many Modiolus populations (see e.g. Brown & Seed, 1978; Rees et al., 2001).
Population samples taken during the present study (Figure 2b-d) were similar
in structure to samples taken in the 1970s and showed little evidence of
change with the possible exception of the sample from Area A which showed
an absence of individuals from the size classes from 15.0mm to 44.9mm.
However, the sample from this site was small; in addition at this site and the
other sites there are individuals as small as 5mm which suggests that
recruitment is still occurring.
%
b) Area A, South Basin
(Present Study 2003)
d) Area C North Basin
(Present study 2003)
n = 218
70.0-7 4.9
70.0-74.9
75.0-7 9.9
75.0-79.9
80.0-8 4.9
80.0-84.9
85.0-8 9.9
85.0-89.9
90.0-94.9
90.0-9 4.9
95.0-99.9
95.0-9 9.9
100.0-104.9
100.0-1 04.9
105.0-109.9
105.0-1 09.9
110.0-114.9
110.0-1 14.9
115.0-119.9
115.0-1 19.9

Summary of findings
A full discussion of the findings will be provided in the final report at the end of
the investigation scheduled for the end of February 2004. The intention of this
interim report is to alert EHS to the current status of the Modiolus reefs based
on findings of the dive survey.
1. In the 1970s & 80s Modiolus beds were known to be extensive in
Strangford Lough (Seed & Brown, 1977; Erwin, 1978, Erwin et al,
1990).
2. The full extent of the beds was not reported in detail until the early
1990s by which time certain areas, particularly those occupied by the
M. modiolus/ Chlamys varia community, were heavily impacted by
mobile fishing gear (Service & Magorrian, 1997).
3. Trawling and dredging are known to damage biogenic reefs and
seabed communities (Watling & Norse, 1998; Cranfield et al. 2003).
Within Strangford Lough trawling has been reported as removing
emergent epifauna (Service & Magorrian, 1997).
4. As a result of recommendations by the then Department of Agriculture
for Northern Ireland (DANI now Department of Agriculture and Rural
Development [DARD]), a number of legislative measures were
introduced in 1993 to manage fishing activity.
5. The most recent survey, prior to SLECI, reported a 3.7km 2 reduction in
area of clumped Modiolus between 1993 and 2000 (Mitchell et al.
2002).
6. Comparison of the current with earlier diving surveys confirms the
decline in:
• North basin Modiolus communities (SCR.ModCvar.) which are now
very much reduced in extent and may no longer be in pristine condition
• South basin Modiolus communities (SCR.ModHAs.).Although these
are more widely distributed than communities in the North basin and
several beds remain, a number of these, show greater or lesser signs
of disruption.
7. In sites where it was possible to collect population samples, population
structure showed little differences from samples taken in the 1970s as
a wide range of sizes were present and, there were individuals as small
as 5mm which suggests that recruitment is still occurring.
SLECI INTERIM REPORT: DECEMBER 2003 11

Conclusions
1. The present study demonstrates that Modiolus reefs are no longer in
‘Favorable Conservation Status’ (The condition in which the habitat or
species is capable of sustaining itself on a long-term basis [Anon,
1997]) in Strangford Lough.
2. There was a 3.7km 2 reduction in clumped Modiolus communities
between 1993 and 2000.
3. Comparison of the current with earlier diving surveys confirms this
decline in Modiolus communities and suggests it is continuing.
4. There is no evidence to suggest recovery of Modiolus communities in
Strangford Lough has been taking place since the conservation
measures, involving legislation to manage fishing activity, were
introduced in 1993 to protect them.
5. There is therefore an urgency to protect remaining Modiolus
communities in Strangford Lough.
6. More detailed mapping, to determine the precise extent and condition
of the Modiolus communities using techniques developed by SLECI
and elsewhere are needed after the final SLECI report is completed.
7. The use of mobile bottom fishing gear poses the most immediate threat
to the few remaining clumped Modiolus communities within the
confines of Strangford Lough cSAC Notwithstanding that Modiolus
recruitment is still occurring in Strangford Lough, the continued use of
mobile bottom fishing gear is likely to hinder natural recovery.
Fishermen trying to develop sustainable practices should therefore be
encouraged.
8. To build on the facts that Modiolus populations are similar in structure
to samples taken in the 1970s and recruitment appears to be still
occurring, a programme for the restoration of Modiolus biogenic reefs
in Strangford Lough should be considered; this should be underpinned
using state-of-the-art techniques to monitor physiological and shell
indicators of stress in Modiolus to ensure success.
SLECI INTERIM REPORT: DECEMBER 2003 12

References
Anon 1997. Natura 2000: European marine sites, an introduction to management.
SNH, EN, EHS (DOE(NI)), JNCC, CCW. Perth, SNH,17pp.
Boyd, R.J. 1973. The relation of the plankton to the physical, chemical and biological
features of Strangford Lough, Co. Down. Proceedings of the Royal Irish Academy,
73B, 317-353.
Brown, R. A. 1976. The Ecology of Modiolus modiolus (L) and Cerastoderma
(=Cardium) edule (L) in Strangford Lough, N. Ireland. PhD Thesis, Queen’s
University of Belfast
Brown, R.A., 1989. Bottom trawling in Strangford Lough: Problems and policies.
North Sea Conference, Rotterdam.
Brown, R.A. & Seed, R., 1978. Modiolus modiolus (L.) – an autecological study. In:
Biology of Benthic Organisms. B.F. Keegan et al. eds. Pergammon Press, Oxford. pp
93-100.
Cranfield H.J., Manighetti, B., Mitchell K.P. & Hill A. 2003. Effects of oyster dredging
on the distribution of bryozoan biogenic reefs and associated sediments in Foveaux
Strait, southern New Zealand. Continental Shelf Research 23, 1337-1357.
Dickie, G., 1857. Report on the Marine Zoology of Strangford Lough. Report British.
Association, 1857.
EHS, 2002. Report on the Modiolus community in Strangford Lough: formal advice to
the minister for the environment from Environment and Heritage Service. 9pp.
Erwin, D. G. 1978. A diving survey of Strangford Lough: the benthic communities and
their relation to substrate – a preliminary account. In: Biology of Benthic Organisms.
B.F. Keegan et al. eds. Pergammon Press, Oxford. pp 215-224.
Erwin, D.G., Picton. B.E., Connor, D.W., Howson, C.W., Gilleece, P. and Bogues,
M.J. 1990. Inshore Marine Life of Northern Ireland. A Report for the Department Of
Environment- Northern Ireland. Ulster Museum, HMSO, 148 pp.
Mitchell, A., Wall, C & Service, M. 2002. Strangford Lough Broadscale subtidal
habitat mapping project: Interim report. EHS. 22pp.
Rees, E.I.S. 2001. Section 3.3. Introduction and history of work on the Pen Llyn
Modiolus reef . In: The establishment of a programme of surveillance and monitoring
for judging the condition and features of Pen Llyn a’r sarnau cSAC: 1. Progress to
March 2001. W.G. Sanderson et al. eds. Bangor, CCW Contract Science Report No
380 (U.K Marine SACs Project), 400pp.
Seed, R. & Brown, R.A. 1977. A comparison of the reproductive cycles of Modiolus
modiolus (L.) Cerastoderma (=Cardium) edule (L.) and Mytilus edulis L. in Strangford
Lough, Northern Ireland. Oecologia (Berl.) 30,173-188.
SLECI INTERIM REPORT: DECEMBER 2003 13

Service, M & Magorrian, B.H. 1997. The extent and temporal variation of disturbance
to epibenthic communities in strangford Lough, Northern Ireland. Journal of the
Marine Biological Association, U.K. 77, 1151-1164.
Watling, L. & Norse, A.E. 1998. Disturbance of the seabed by mobile fishing gear: A
comparison with forest clear-cutting. Conservation Biology 12, 1180-1197.
SLECI INTERIM REPORT: DECEMBER 2003 14

Appendix 1. Ulster Museum sites. Line illustrates approximate division of
north and south basins
NISS & Ulster Museum divesite positions1975-85
Legend
1975-85 sites
Other communities
Modiolus beds
Sparse Modiolus
Nephrops ground
Coastline
Islands
10mContour
SLECI INTERIM REPORT: DECEMBER 2003 15

Appendix 2 – SLECI dive-site details. Sites marked green have intact
Modiolus/Chamys ,[SCR.ModCvar.], those marked blue have intact
Modiolus/hydroids[SCR.ModHAs.]. N – North basin; S – South basin
Field
Site No
DiveNo Description
1 030702/03 S Bare muddy seabed with scattered shells
2 030702/04 S Scattered dead Modiolus shell, some live Modiolus clumps partially buried in mud
3 030703/01 N Scattered dead Modiolus shell
4 030703/02 N Mud with dead shell, some Modiolus/Chlamys clumps
5 030703/03 N Mud with dead shell, occasional boulder with lots of hydroids
6 030703/04 N Fine mud, Sagartiogeton laceratus
7 030704/01 S Boulders on gravel & sand, vast quantities of Ciona intestinalis
8 030704/02 S Gravelly mud dead shell, cobbles
9 030704/03 S Virgularia
10 030704/04 S Gravelly mud dead shell, cobbles, Cerianthus, Virgularia
11 030707/01 N Continuous live Modiolus modiolus
12 030707/02 N Dead shell with Hydrallmania
13 030707/03 N Mud with broken shell, large no's of Pandalus montagui
14 030707/04 N Mud with dead shell, frequent Suberites carnosus
15 030708/01 N Featureless mud very few Nephrops, Hydrallmania
16 030708/02 S Scattered live Modiolus modiolus and broken dead shell
17 030708/03 S Muddy Sand/ Amphiura
18 030708/04 S Cobbles and coarse gravel Neopentadactyla
19 030709/01 S Mud w. shell/Gravel becoming boulders covered with Ascidiella
20 030709/02 S Gravel & cobbles with Ophiocomina and lots of hydriods
21 030709/03 S Virgularia/ firm mud
22 030709/04 S Virgularia
23 030721/01 S Modiolus modiolus clumps covered with sediment
24 030721/03 S Mud with Scattered broken shell & Alcyonium/Sagartia elegans
25 030721/04 S Dense dead Modiolus shell
26 030722/01 N Scattered dead Modiolus shell
27 030722/02 N Scattered dead Modiolus shell
28 030722/03 N Few live Modiolus/Chlamys becoming scattered dead Modiolus shell
29 030722/04 N Scattered dead Modiolus shell then Nephrops
30 030722/05 N Cobbles, shell, lots of Ophiocomina
31 030724/01 N Mud with dead shell
32 030724/02 N Scattered Sagartia, lots of Epizoanthus, Mud with scattered broken shell
33 030724/03 N Mud with dead shell
34 030724/04 N Mud with dead shell, lots of Asterias in feeding clumps
35 030725/01 N Shelly mud, large no's of Ostrea edulis and Pandulus montagui
36 030725/02 & 3 N Continuous live Modiolus modiolus
37 030728/01 & 02 N Continuous live Modiolus modiolus
38 030728/03 N Oyster bed
39 030729/01 N Scattered live then dead Modiolus modiolus shell
40 030729/02 N Scattered dead Modiolus shell
41 030729/03 & 04 N Scattered dead Modiolus shell
42 030730/01 S Nephrops bed/Sagartiogeton laceratus
43 030730/02 S Nephrops bed
44 030730/03 N Mud with dead shell
45 030730/04 N Nephrops bed
46 030731/01 N Featureless mud
47 030731/02 N Mud with dead shell
SLECI INTERIM REPORT: DECEMBER 2003 16

48 030731/03 N Continuous live Modiolus modiolus
49 030731/04 S Modiolus modiolus clumps covered with sediment
50 & 51 030801/01 & 02 S Modiolus modiolus clumps
52 030801/03 S Ascidiella on boulders
53 030801/04 S Nephrops bed/Sagartiogeton laceratus
54 030811/01 S Soft mud w dead Modiolus shell
55 030811/02 S Fine Sand/Mud w well mixed small fragments of shell. Clusters of large unbroken shell.
56 030811/03 N Soft mud w anoxic layer 1" below surface
57 030811/04 S Nephrops/Sagartiogeton laceratus
58 030812/01 N Fine soft mud littered w Modiolus, Venerupis & Chlamys shells
59 030812/02 N Mud with dead shell
60 030812/03 N Fine mud w well mixed small shell, some areas of intact shell, some mud w Goneplax
burrows, In shallower water boulders on muddy substrate
61 030812/04 N Dead shell, mud, Antedon, Hydrallmania, Thyone roscovita
62 030812/05 N Fine mud, burrows
63 030813/01,02,03,0
4 N
Continuous live Modiolus modiolus/ Some clumps
64 030813/05 S Dead Maerl gravel w Laminarians in shallow water, Then covered w whole dead
Modiolus shell
65 030813/06 S Scattered dead Modiolus shell, scattered large living Modiolus
66 030814/01 N Scattered dead modiolus shell
67 030814/02 N Scattered dead modiolus shell, occasional boulders in deepest part of dive
68 030814/03 N Nephrops bed
69 030814/04,05,06 S Modiolus modiolus clumps
70 030815/01 S Cobbles with Ophiocomina, Hydroids, Boulders and gravel
71 030815/02 S Muddy substrate
72 030815/03 S Scattered Modiolus modiolus clumps becoming mud with cobbles in deeper water
73 030815/04 S Gravel, Urticina felina
74 030815/05 S Boulders /cobbles/pebbles on gravelly sand covered w red algae
75 031016/01 S M. modiolus clumps
76 031016/02 S Thick dead Modiolus shell
77 031016/03 N Continuous live M. modiolus
78 031016/04 N Some clumped M. modiolus, much dead shell
79 031016/05 S Dead M. modiolus shell, small boulders in shallow water
80 031016/06 S Cobbles, pebbles, boulders covered in red algae, hydroids and sponges
81 031017/01 S Boulders covered in hydroids and ascidians
82 031017/02 S Medium density M. modiolus clumps
83 031017/03 S NA
84 031017/04 N Fine mud with lots of dead oyster shell, some dead M. modiolus
85 031017/05 N Muddy sand
86 031017/06 S NA
SLECI INTERIM REPORT: DECEMBER 2003 17