Table 12. — Summary of apparent biomasses of major taxonomic groups in the Bering Sea, 1976 spring trawl survey.' 





Estimated 



biomass for 



total survey 



area (t) 



Proportic 

 of total 

 biomass 



in 



Estimated biomass by i 



iubarea (t) I,J 







Proportion of total estimated 

 biomass by taxa 





Taxa 



1 



2 



3 



4 



Slope 



1 



2 



3 



4 



Slope 



Gadidae 



(778,386) 



0.137 



14,488 



(502,974) 



(192,348) 



7,899 



(60,813) 



0.019 



0.646 



0.247 



0.010 



0.078 



Pleuronectidae 



(2,810,815) 



0.493 



(1,370,101) 



(755,013) 



169,056 



(483,689) 



41,602 



0.488 



0.269 



0.057 



0.172 



0.015 



Cottidae 



360,172 



0.063 



132,326 



82,051 



29,016 



114,238 



2,447 



0.367 



0.228 



0.081 



0.317 



0.007 



Zoarcidae 



37,766 



0.007 



483 



12,142 



21,9% 



2,431 



734 



0.013 



0.321 



0.582 



0.064 



0.019 



Rajidae 



26,039 



0.005 



— 



9,198 



8,424 



122 



8,320 



— 



0.353 



0.323 



0.005 



0.319 



Agonidae 



59,830 



0.011 



26,562 



9,566 



1,872 



21,875 



61 



0.443 



0.160 



0.031 



0.365 



0.001 



Other fish 



70,961 



0.012 



20,766 



7,359 



21,528 



16,407 



5,139 



0.292 



0.103 



0.302 



0.230 



0.072 



Total fish 



(4,143,969) 



0.727 



(1,564,726) 



(1,378,303) 



(435,240) 



(646,540) 



(119,117) 



0.378 



0.333 



0.105 



0.156 



0.029 



Porifera 



38,561 



0.007 



29,459 



5,151 



468 



3,646 



61 



0.760 



0.133 



0.012 



0.094 



0.002 



Coelenterata 



48,699 



0.009 



18,352 



9,934 



9,828 



9,115 



979 



0.381 



0.206 



0.204 



0.189 



0.020 



Mollusca 



89,049 



0.016 



12,556 



10,302 



27,612 



35,851 



2,937 



0.141 



0.115 



0.309 



0.402 



0.033 



Gastropoda 



82,291 



0.014 



11,591 



8,095 



26,676 



34,636 



918 



0.141 



0.099 



0.326 



0.423 



0.011 



Pelecypoda 



1,391 



<0.001 



483 



37 



47 



608 



1 



0.411 



0.031 



0.040 



0.517 



<0.001 



Cephalopoda 



5,367 



<0.001 



2 



2,208 



936 



18 



2,019 



< 0.001 



0.426 



0.181 



0.003 



0.390 



Crustacea 



967,218 



0.170 



219,255 



225,547 



181,584 



332,992 



8,076 



0.227 



0.233 



0.188 



0.344 



0.008 



Total crabs 



964,236 



0.169 



218,772 



224,811 



180,180 



332,385 



7,648 



0.227 



0.233 



0.187 



0.345 



0.008 



Chionoeceres spp. 



770,832 



0.135 



117,837 



186,546 



151,632 



307,471 



7,219 



0.153 



0.242 



0.197 



0.399 



0.009 



Paralilhodes spp. 



131,586 



0.023 



84,032 



33,115 



11,232 



3,038 



61 



0.639 



0.252 



0.085 



0.023 



<0.001 



Total shrimp 



2,186 



< 0.001 



89 



368 



1,404 



36 



428 



0.038 



0.158 



0.604 



0.015 



0.184 



Other Crustacea 



795 



<0.001 



483 



368 



— 



608 



— 



0.331 



0.252 



— 



0.417 



— 



Echinodermata 



329,959 



0.058 



124,116 



18,029 



38,376 



143,405 



5,567 



0.377 



0.055 



0.116 



0.435 



0.017 



Asteroidea 



261,185 



0.046 



111,076 



3,311 



11,232 



134,291 



1,407 



0.425 



0.013 



0.043 



0.514 



0.005 



Echinoidea 



5,566 



< 0.001 



4,346 



736 



187 



— 



122 



0.806 



0.137 



0.035 



— 



0.023 



Ophiuroidea 



53,271 



0.009 



2,898 



13,982 



27,144 



9,115 



367 



0.054 



0.261 



0.507 



0.170 



0.007 



Holothuroidea 



10,137 



0.002 



6,278 



11 



9 



608 



3,610 



0.597 



0.001 



<0.001 



0.058 



0.343 



Ascidiacea 



59,631 



0.010 



25,113 



11 



140 



34,636 



1 



0.419 



<0.001 



0.002 



0.578 



<0.001 



Other invertebrates 



19,877 



0.003 



1,932 



736 



2,340 



14,584 



- 



0.099 



0.038 



0.119 



0.744 



— 



Total invertebrates 



1,552,995 



0.273 



430,782 



269,-00 



260,208 



574,229 



17,620 



0.277 



0.174 



0.168 



0.370 



0.011 



Total catch 



(5,696,964) 



1.000 



(1,995,508) 



(1.648,003) 



(695,448) 



(1,220,769) 



(136,737) 



0.350 



0.289 



0.122 



0.214 



0.024 



Geographical area 



























(km 1 ) 



337,930 



— 



82,100 



62,550 



-4.5-n 



103.310 



10,400 



— 



— 



— 



— 



— 



'Parentheses indicate estimates of questionable accuracy due to potential sampling biases. 

 'Biomass = (CPUE/trawl width) x (geographical area) x (10"' t/kg), where trawl width 

 'See Figure 3. 



0.017 km. Metric tons 



The most frequently occurring fish taxa among all areas were 

 walleye pollock 01%), yellowfin sole (71%), Pacific cod (63%), 

 Alaska plaice (60%), and Greenland turbot (59%). 



Most frequently occurring invertebrate taxa overall were snow 

 crab, C. opilio (77%) and C. bairdi (72%), unidentified snails 

 (68%), unidentified hermit crabs (55%), and unidentified starfish 

 (48%). 



Relative abundance. — Apparent abundance observed during 

 the spring 1976 survey is summarized in Tables 14-19. With the 

 exception of the estimates of questionable accuracy obtained for 

 walleye pollock, yellowfin sole, and Alaska plaice, Tables 14-19 

 provide comparisons of relative apparent densities and relative 

 species composition (on a weight basis) between geographical 

 regions of the study area. 



Table 14 summarizes the observed overall mean abundance. 

 Yellowfin sole and walleye pollock showed the highest apparent 

 mean abundance, accounting for 48.2% of the overall mean total 

 catch. The 20 most abundant fish taxa (7.6% of 264 total fish and 

 invertebrate taxa recorded during the survey) accounted for 

 71.9% of the overall total catch. 



In general, fauna! similarity (as measured by the number of 

 common taxa and the relative proportion of the total CPUE's) 

 between subareas followed similarity in physical environment. 

 Faunal composition was most similar between inner shelf 



subareas 1 (Table 15), and 4N and 4S (Table 18), with 19 common 

 taxa among the 20 most abundant in each subarea. Yellowfin sole 

 ranked highest in abundance in both subareas, followed by 

 Alaska plaice, sculpins, and rock sole. Of the 19 common taxa 

 between subareas, most were more abundant in subarea 1 . 



Based on the above criteria, outer shelf subareas 2, 3N, and 3S 

 were also similar in faunal composition, with 13 taxa in common 

 among their most abundant 20 (Tables 16, 18). In subarea 2, 

 yellowfin sole was most abundant, followed by walleye pollock. 

 In subareas 3N and 3S, walleye pollock ranked first, followed by 

 yellowfin sole. Rock sole, flathead sole, Alaska plaice, and Pacific 

 halibut were relatively abundant in subarea 2, but not in subareas 

 3N and 3S. Relatively abundant taxa in subareas 3N and 3S, but 

 not in subarea 2, were Greenland turbot, eelpouts, and Pacific 

 herring, Clupea harengus pallasi. 



The slope subareas showed a relatively different faunal com- 

 position from all shelf subareas (Table 19). Dissimilarities were 

 most marked between the slope subarea and inner shelf subareas 

 1, 4N, and 4S, with only 8 or 9 common taxa among the 20 most 

 abundant in each area. There were 1 1 or 12 common taxa between 

 the slope subarea and outer shelf subareas 2, 3N, and 3S. Walleye 

 pollock was the most abundant species on the slope, with large 

 flounders (arrowtooth flounder, Greenland turbot, and Pacific 

 halibut), Pacific cod, and skates also showing relatively high den- 

 sities. Deepwater taxa that were taken in abundance only in the 



22 



