Synopsis of Biological Data on the Chum Salmon, Oncorhynchus keta

Table 41.--Relation <strong>of</strong> other fish to chum salmon fry as competitors for
food in Khor River, U.S.S.R. (Levanidov, 1959)
Species Felati ve Equivalent Compet it i ve
abundance <strong>of</strong> feeding value 2
compet i tion 1
Percent Percent
Lenok 5. 0 26 .1 55 .7
Grayling 2. 0 4. 8 h.l
Amur ide 7.0 1.1 3.3
Common eudgeon 28 . 0 1.2 14.0
Lagovsky's minnow 36 . 0 1.4 20.9
Common minnow 12.0 0.2 1.2
Stone loach 0 . 3 0.8 o.?
Ninespine stickleback 8. 0 0.1 0.4
Bullhead 1.5 0.1 0.1
Burbot 0 . 2 1. 0 0.1
1 Equivalent <strong>of</strong> feeding competition is best defined by an example. For the
lenok it means that one lenok ate the same quantity <strong>of</strong> food organisms as
26.1 chum salmon fry.
2 The figures in this column are the product <strong>of</strong> the first two columns expressed
in percentage.
'Figure 13.--Relation <strong>of</strong> food organisms in Memu River,
Japan (Hikita and Nagasawa, 1960).
century (Shepard et al., 1967). Their efficiency
has been improved by the development <strong>of</strong>
power drums and blocks for handling the nets
and by the use <strong>of</strong> nylon for the webbing (International
North Pacific Fisheries Commission,
1962a). Before 1959 (when almost all traps
were abolished by regulation), an extensive
trap-net fishery existed in Alaska. Traps were
also widely used in Washington and Oregon
61
before 1934 and to a much lesser extent in
British Columbia before 1958 (Shepard et al.,
1967).
At present, gill nets, purse seines, and
beach seines are the principal types <strong>of</strong> gear
(table 43). Some chum salmon are also taken
by reef nets, holling, traps, and fish wheels
(International North Pacific Fisheries Commission,
1962a; 1962b). The percentage <strong>of</strong>
catches taken by types <strong>of</strong> gear in 1966 (data
from INPFC Statistical Yearbook, 1966) was
as follows:
Catches
Thousands <strong>of</strong> Seines Gill nets Other gear
fish Percent Percent Percent
Alaska 6,456 73.5 26.3 0.2
British
Columbia 1,311 44.2 55.5 0.3
Washington 425 48.2 41.1 10.7
Oregon 1 0 100.0 0
Along the North American coast, regulations
establish the length and sometimes the mesh
size and depth <strong>of</strong> gill nets. Gill nets us ed for
chum and other species <strong>of</strong> salmon are generally
made with multifilament nylon and have mesh