Landingham et a I.: Feeding habits of juvenile Pacific salmon 
287 
Table 1 
Number of purse-seine sets by time period and habitat and subsample size by species of juvenile salmon used in diet analyses. 
BC = British Columbia; AK = Alaska. 
Number of sets 
catching Number of fish 
Habitat 
Number 
of sets 
juvenile 
salmon 
Pink 
Chum 
Sockeye 
Coho 
Chinook 
August 1983 
Inside inlet 
15 
3 
21 
23 
2 
14 
1 
Inside passage 
39 
23 
142 
112 
44 
88 
2 
Outer coast inlet 
27 
8 
60 
47 
0 
21 
0 
Outside waters 
8 
4 
15 
2 
9 
26 
0 
Total 
89 
38 
238 
184 
55 
149 
3 
July 1984 
Inside inlet 
13 
5 
14 
17 
12 
63 
10 
Inside passage 
5 
2 
20 
3 
9 
44 
0 
Outer coast inlet 
14 
5 
8 
3 
0 
28 
0 
Outside waters (BC) 
21 
11 
69 
30 
55 
7 
3 
Outside waters (AK) 
33 
15 
94 
40 
83 
27 
1 
Total 
86 
38 
205 
93 
159 
169 
14 
August 1984 
Inside inlet 
18 
6 
35 
16 
10 
82 
6 
Inside passage 
19 
7 
61 
10 
5 
73 
10 
Outer coast inlet 
4 
1 
0 
12 
0 
3 
0 
Outside nearshore 
26 
20 
183 
97 
80 
55 
5 
Outside offshore 
11 
10 
93 
41 
52 
12 
0 
Total 
78 
44 
372 
176 
147 
225 
21 
All periods combined 
Inside inlet 
46 
14 
70 
56 
24 
159 
17 
Inside passage 
63 
32 
223 
125 
58 
205 
12 
Outer coast inlet 
45 
14 
68 
62 
0 
52 
0 
Outside waters 
99 
60 
454 
210 
279 
127 
9 
Total 
253 
120 
815 
453 
361 
543 
38 
Stomach analysis 
Each fish was weighed to the nearest milligram and 
measured to the nearest millimeter fork length (FL) 
in the laboratory. Stomachs were excised and placed 
in 70% isopropyl alcohol. During analysis, stomach 
fullness on a scale of 0-6 (0=empty, 6=distended) and 
digestion on a scale of 1-4 (l=fresh prey items, 
4=completely digested) were visually estimated. 
Stomach contents were weighed, and prey items were 
separated, identified to the lowest convenient taxon, 
and counted. Up to 100 individuals of each prey cat- 
egory that had been removed in good condition from 
the stomach were used to measure initial wet weights. 
Prey fish in an advanced state of digestion were as- 
signed to discrete weight categories based on the most 
complete specimens encountered: small (estimated 
6.0 mg), medium (184.4 mg), and large (580.5 mg). Dry 
weights were obtained by drying the samples in an oven 
at 60°C until constant weights were obtained. 
Sampling and analysis of prey assemblages 
Prey assemblages were sampled with neuston and 
plankton nets in the areas fished in 1984. Neuston 
collections were made with a rectangular 100 x 35- 
cm-opening neuston-net frame containing a conical 
505-pm-mesh net; tows were made at 45 of 54 out- 
side-water locations, 7 of 14 outer-coast-inlet loca- 
tions, and 5 of 18 inside-water locations. The neus- 
ton net was towed horizontally, half-submerged, so 
that it sampled the water column from the surface 
to approximately 17 cm depth (Brodeur, 1989; 
Brodeur 2 ). The plankton collections were made with 
a 70-cm diameter conical plankton net of 303-pm 
mesh; tows were made along purse-seine transects 
at four 4-km locations and six 16-km locations in 
2 Brodeur, R. D., W. G. Pearcy, B. C. Mundy, and R. W. Wisseman. 
1987. The neustonic fauna in coastal waters of the northeast 
Pacific: abundance, distribution, and utilization by juvenile 
salmonids. Oregon State Univ. Publ. ORESU-T-87-001, 61 p. 
