294 
Fishery Bulletin 96(2), 1 998 
Inside water (IRI) 
(partitioned into inlets and passages) 
Outside waters and 
outer coast inlets (IRI) 
80 60 
40 
20 
0 20 
40 60 80 
i i 
INLET 
AUGUST 1983 
1 " " 
ll 
NO DATA 
I 
NO DATA 
— 1 1 | 
INLET 
AUGUST 1983 
AUGUST 1983 
AUGUST 1983 
■ r 
n = 9 
n = 44 
tS».'U:'v 
...Tl 
t 
INLET 
JULY 1984 
\T. 
NO DATA 
INLET 
JULY 1984 
n= 12 
■ 
N. BRITISH COLUMBIA 
n = 55 
l nOOnuL 
JULY 1984 
JULY 1984 
n = 9 
1 
J 
u - 
n = 83 
INLET 
AUGUST 1984 
NO DATA 
INLET 
AUGUST 1984 
n« 10 
i 
1 
PASSAGE 
■ 
AUGUST 1984 
AUGUST 1984 1 
1 
n-80 
n= 5 
C 
0-37 KM 
POOLED HABITATS 
r 
AUGUST 1984 
AND YEARS 
frTTTT 
1 
n- 52 
n = 361 
1 ...... 
t: ''T :T:V 
1f ‘ ” ' " 1 
EM 
■■ Calanoid copepods HTTP 
i 1 Decapod larvae ► — J 
Euphausiids 
Fishes 
L—J Hyperiid amphipods 
E3 Tunicates 
Figure 6 
Index of relative importance (IRI) of principal prey of juvenile sockeye salmon in inside and outside waters and 
outer coast inlets of southeastern Alaska in 1983 and 1984 and outside waters and outer coast inlets of northern 
British Columbia in 1984. 
from outside waters; the reverse was observed for 
sockeye salmon. 
Salmon diet and the prey assemblages 
Neuston samples from the outside waters of British 
Columbia and southeastern Alaska included 13 and 
14 major taxa, respectively (Table 7). In British Co- 
lumbia, decapod larvae made up 83% of the number 
of prey, hyperiid amphipods 12%, calanoid copepods 
4%, and all other taxa <1%. Prey diversity of neus- 
ton samples was more even for southeastern Alaska 
than for British Columbia; half of the 14 taxa repre- 
sented >2% of the total abundance. In Alaska, 
calanoid copepods were the most abundant organ- 
ism (59% of the total), decapod larvae were second 
(21%), and gammarid amphipods were third (9%). 
The density of neustonic organisms was about five 
times greater in samples from British Columbia than 
in those from southeastern Alaska. 
In zooplankton samples, the number of individuals 
and dominant taxa differed with time and habitat 
(Table 7). Zooplankton abundance in outside waters was 
about twice that of inside waters of southeastern Alaska 
in July 1984. Calanoid copepods were the dominant 
organisms in the samples (90% of total abundance). 
The PSI indicated little relationship between prey 
consumed by salmon and prey available in the envi- 
ronment (Table 8). Neuston samples were generally 
more similar to salmon diet than were zooplankton 
samples. Similarity for the neuston samples ranged 
from 0% to 37.8% and averaged from 9.1% for sock- 
eye salmon to 16.7% for coho salmon (Table 8). The 
PSI values for the plankton samples ranged from 
0.2% to 24.9% and averaged from 2.2% for chum 
salmon to 9.3% for sockeye salmon. 
