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Fishery Bulletin 95(2), 1997 
dissolved oxygen content determined benthic fish as- 
semblages observed off the west coast of central Africa. 
Relatively few fisheries resource surveys have been 
conducted in Arctic waters off Alaska; only three have 
been conducted in the northeastern Chukchi Sea 
(A1 verson and Wilimovsky, 1966; Frost and Lowry, 
1983; Fechhelm et al. 1 ). These were limited in geo- 
graphic coverage and not designed to address ques- 
tions on environmental factors influencing fish dis- 
tribution. The studies were, however, important first 
steps in determining factors influencing the distri- 
bution and abundance of fishes in Arctic waters. 
The goal of our study was to determine the distri- 
bution and abundance of demersal fishes, the pres- 
ence of species assemblages, and the relationship of 
such assemblages to oceanographic features in the 
northeastern Chukchi Sea, Alaska. Results from in- 
vestigations of the distribution and relative abun- 
dance of infaunal and epifaunal mollusks in the east- 
ern Chukchi Sea suggest that invertebrate assem- 
blages may be associated with differences in hydro- 
graphic conditions and sediment types (Feder et al., 
1994, Feder et al. 2 ). On the basis of these findings, 
we hypothesized that there would be onshore-off- 
shore and north-south differences in demersal fish 
abundance, biomass, and assemblages, and that 
these differences would be related to hydrographic 
conditions and sediment type. 
Materials and methods 
Our study area was north of 68°N (Point Hope, 
Alaska), east of 168°58'W, and limited in northward 
extent by weather and sea ice (Fig. 1). 
The shelf of the northeastern Chukchi Sea is rela- 
tively shallow, gently sloping offshore to depths of 
30-50 m in the study area. Bottom sediments in the 
region are poorly sorted, trending to relatively coarse 
sediments on the inner shelf between Point Hope and 
Point Barrow, and shifting offshore to muds contain- 
ing various proportions of gravel and sand (Sharma, 
1979; Naidu, 1988). Sediments in the more north- 
erly offshore region contain a higher percentage of 
water and a lower percentage of gravel than sedi- 
ments found in the more southernly offshore area 
(Feder et al. 2 ). 
1 Fechelm, P, C. Craig, J. S. Baker, and B. J. Gallaway. 
1985. Fish distribution and use of near shore waters in the 
northeastern Chukchi Sea. U.S. Dep. Commer., NOAA, 
OCSEAP Final Rep. 32, p. 121-297. 
2 Feder, H. M., A. S. Naidu, M. J. Hameedi, S. C. Jewett, and W. 
R. Johnson. 1990. The Chukchi Sea continental shelf: 
benthos-environmental interactions. U.S. Dep. Commer., 
NOAA, OCSEAP Final Rep. 68:25-311. 
The Chukchi Sea consists of several water masses 
( Weingartner, in press): Alaska Coastal Water (ACW) 
and the Resident Chukchi Water (RCW) commonly 
dominate the study area. The ACW is relatively 
warm, low-salinity water lying nearshore. It is a 
mixture of Bering Shelf water and freshwater that 
comes from western Alaskan rivers, primarily the 
Yukon. The RCW is relatively cold, high-salinity 
water that lies seaward of the ACW. The RCW is ei- 
ther advected onshore from the upper layers of the 
Arctic Ocean or is remnant ACW from the previous 
winter. The ACW and RCW masses are separated by 
a hydrographic front that tends to be located between 
the 25-m and 40-m isobaths and that intersects the 
coast between Icy Cape and Point Franklin (Johnson, 
1989; Weingartner, in press; Feder et al. 2 ). 
Sampling occurred during August and September 
in 1990 and 1991. In 1990, 48 stations were occu- 
pied along 11 transects perpendicular to shore; 16 
stations were occupied in 1991, including 8 that were 
sampled in 1990 (Fig. 1; station locations, water 
depths, bottom temperatures, and bottom salinities 
are given in Smith et al., in press, b). In 1990, 
nearshore stations were established closer to one 
another than were stations farther offshore in order 
to increase the probability of having two stations in 
each transect inshore of the historical position of the 
“bottom (hydrographic) front.” Weather and ice con- 
ditions dictated the sequence of stations sampled. Sta- 
tions were numbered to reflect the sampling sequence. 
Two samples for each category (fishes and inver- 
tebrates) were collected at each station by towing a 
standard 83-112 survey otter trawl 3 for 30 minutes. 
However, because of weather condition and torn nets, 
only one haul was made at station 31 in 1990 and at 
stations 16, 91-33, 91-34, and 91-35 in 1991. The 
trawl had a 25.2-m head rope, 34.1-m footrope, tick- 
ler chain, and codend of 8.9-cm stretched mesh with 
a 3.2-cm stretched mesh liner. The area swept by the 
trawl was calculated by multiplying the length of 
each trawl haul (beginning and ending location of 
each tow was determined with “Global Positions Sys- 
tem”) by the width of the trawl during fishing (the 
trawl width at the wings and height of the headrope 
above the footrope were determined with a Scanmar™ 
electronic mensuration unit). 
Upon retrieval of the trawl, the entire catch was 
either weighed in the net with an electronic load cell 
or in baskets on a mechanical platform. Fish were 
sorted to the lowest taxa possible, counted, and 
weighed with a mechanical platform scale. Fish abun- 
dance (fish/km 2 ) and biomass (g/km 2 ) were deter- 
3 Sample, T. E. 1994. Alaska Fisheries Science Center, Natl. 
Mar. Fish. Serv., NOAA, Seattle, WA. Personal commun. 
