Barber et a I,: Demersal fish assemblages of the northeastern Chukchi Sea 
205 
gravel accounted for 37.1% of the variance among 
stations, that epifaunal and infaunal abundances and 
gravel accounted for 27.8% of the variation, and that 
gravel and sand accounted for an additional 15.6% 
of the variation. 
Discussion 
The northeastern Chukchi Sea lies between the Arc- 
tic Ocean and the Bering Sea and serves as a con- 
duit for water flowing between these two bodies of 
water. In terms of oceanographic flow, this is a dy- 
namic region, with a net water transport from the 
Bering Sea into the Arctic Ocean. Flow reversals oc- 
cur in response to regional storm events (primarily 
during the seasonal ice-forming period). Therefore, 
oceanographic information used in this study repre- 
sents but a short-term snapshot of environmental 
conditions within the region. Information on sedi- 
ment distribution and associated invertebrate fauna 
was considered to provide a long-term integration of 
oceanographic conditions within the region. Even 
though invertebrate fauna may be influenced by hy- 
drographic conditions in much the same way as ich- 
thyofauna are influenced by these conditions, in this 
study they were used as independent variables. This 
designation was made in part because invertebrates 
tend to be less mobile than fishes and because, in eco- 
logical terms, invertebrates provide habitat and food 
for many fish species. 
During this study, 66 species representing 14 fami- 
lies were collected, 56 in 1990 and an additional 10 
in 1991. This number is similar to the number of 
species (52) collected in the Chukchi Sea by A1 verson 
and Wilimovsky (1966) and is greater than the 29 
species taken in the nearshore Chukchi Sea by 
Fechelm et al. 1 and the 19 species captured west of 
Point Barrow by Frost and Lowry (1983). As in our 
study, Boreogadus saida was the dominant species 
captured during each of these surveys. Other impor- 
tant species reported by these authors that were im- 
portant in our study included Mallotus villosus, 
Liopsetta glacialis, Lycodes polaris, and Icelus bicornus. 
The number, diversity, and biomass of fish species 
documented during our study are comparable to those 
in more southerly areas of the North Pacific Ocean. 
Day and Pearcy (1968) found 67 species represent- 
Table 3 
Estimated mean abundance (fish/km 2 ), number of species, Shannon Wiener diversity, and evenness found in the six assemblages 
for the 21 most abundant demersal fish species determined from the cluster analysis with the Bray-Curtis dissimilarity index. 
Assemblage 
Species 
1 
2 
3 
4 
5 
6 
Boreogadus saida 
43,733 
16,419 
5,280 
8,172 
16,096 
6,100 
Eleginus gracilis 
684 
2 
170 
19 
10,956 
0 
Myoxocephalus sp. 
3,391 
49 
44 
2 
4,492 
0 
Gymnocanthus tricuspis 
1,005 
87 
889 
156 
2,618 
7 
Hippoglossoides robustus 
1,599 
72 
0 
61 
15 
3 
Myoxocephalus verrucosus 
178 
0 
429 
177 
773 
9 
Artediellus scaber 
20 
0 
0 
11 
1,061 
4 
Theragra chalcogramma 
69 
0 
0 
26 
861 
0 
Triglops pingeli 
70 
3 
120 
59 
722 
0 
Mallotus villosus 
437 
0 
0 
40 
0 
0 
Lycodes palearis 
453 
0 
0 
7 
0 
0 
Clupea harengus pallasi 
195 
0 
0 
139 
323 
0 
Lumpenus fabricii 
235 
18 
2 
14 
141 
0 
Lycodes polaris 
260 
64 
2 
0 
6 
0 
L. raridens 
76 
7 
4 
284 
13 
5 
Podothecus acipenserinus 
60 
0 
18 
5 
280 
0 
Gadus macrocephalus 
21 
0 
1 
6 
273 
0 
Liparis gibbus 
129 
2 
0 
15 
29 
0 
Osmerus mordax 
0 
0 
0 
0 
258 
0 
Hemilepidotus papilio 
89 
0 
0 
13 
0 
0 
Artediellus sp. 
80 
0 
0 
0 
20 
0 
Number of species 
20 
10 
11 
18 
18 
6 
Shannon Wiener diversity 
0.35 
0.05 
0.37 
0.25 
0.72 
0.02 
Evenness 
0.27 
0.05 
0.35 
0.20 
0.57 
0.02 
