Table 17.— The 20 most abundant fish taxa recorded during the spring 1976 

 Bering Sea demersal trawl survey, in order of observed abundance, subarea 3.' 



Table 19. — The 20 most abundant fish taxa recorded during the spring 1976 Bering 

 Sea demersal trawl survey, in order of observed abundance, slope subarea. 1 







CPUE 



Proportion of 



Cumulative 







CPUE 



Proportion of 



Cumulative 



Rank 



Taxon 



(kg/km) 1 



total CPUE' 



proportion 



Rank 



1 



Taxon 



Walleye pollock 



(kg/km) 1 

 (74.34) 



total CPUE' 

 0.333 



proportion 



1 



Walleye pollock 



(36.54) 



0.246 



0.246 



0.333 



2 



Yellowfin sole 



21.67 



0.146 



0.392 



2 



Arrowtooth flounder 



32.09 



0.144 



0.477 



3 



Unidentified sculpins 



5.21 



0.035 



0.427 



3 



Pacific cod 



25.09 



0.112 



0.589 



4 



Greenland turbot 



4.82 



0.032 



0.459 



4 



Greenland turbot 



16.55 



0.074 



0.663 



5 



Pacific cod 



4.59 



0.031 



0.490 



5 



Unidentified skates 



12.23 



0.055 



0.718 



6 



Pacific herring 



3.60 



0.024 



0.514 



6 



Pacific halibut 



11.74 



0.053 



0.771 



7 



Unidentified eelpouts 



2.88 



0.019 



0.533 



7 



Flathead sole 



6.06 



0.027 



0.798 



8 



Rock sole 



2.67 



0.018 



0.551 



8 



Unidentified rattails 



3.69 



0.017 



0.815 



9 



Flathead sole 



2.18 



0.015 



0.566 



9 



Unidentified sculpins 



2.93 



0.013 



0.828 



10 



Alaska plaice 



1.92 



0.013 



0.579 



10 



Pacific ocean perch 



2.05 



0.009 



0.837 



11 



Unidentified skates 



1.43 



0.010 



0.589 



11 



Rock sole 



1.25 



0.006 



0.843 



12 



Polar eelpout 



1.43 



0.010 



0.599 



12 



Big skate 



1.02 



0.005 



0.848 



13 



Arrowtooth flounder 



0.65 



0.004 



0.603 



13 



Unidentified eelpouts 



0.85 



0.0O4 



0.852 



14 



Unidentified snailfish 



0.48 



0.003 



0.606 



14 



Searcher 



0.72 



0.003 



0.855 



15 



Great sculpin 



0.46 



0.003 



0.609 



15 



Unidentified snailfish 



0.72 



0.003 



0.858 



16 



Sturgeon poacher 



0.25 



0.002 



0.611 



16 



Sablefish 



0.65 



0.003 



0.861 



17 



Black skate 



0.24 



0.002 



0.613 



17 



Bigmouth sculpin 



0.36 



0.002 



0.863 



18 



Canadian eelpout 



0.23 



0.002 



0.615 



18 



Canadian eelpout 



0.29 



0.001 



0.865 



19 



Capelin 



0.21 



0.001 



0.616 



19 



Spinyhead sculpin 



0.25 



0.001 



0.865 



20 



Myoxocephalus spp. 



0.21 



0.001 



0.617 



20 



Rex sole 



0.25 



0.001 



0.866 



'See Figure 3. 



"Overall catch per unit effort, kg/km trawled. Total effort = 359.4 km. 

 Parentheses indicate estimates of questionable accuracy due to potential sampling 

 problems. 



'Proportion of total catch per unit effort, all fish and invertebrates combined. 

 Total CPUE = 148.61 kg/km. 



'See Figure 3. 



'Overall catch per unit effort, kg/km trawled. Total effort = 142.9 km. 

 Parentheses indicate estimates of questionable accuracy due to potential sampling 

 problems. 



'Proportion of total catch per unit effort, all fish and invertebrates combined. 

 Total CPUE = 223.53 kg/km. 



Table 18.— The 20 most abundant fish taxa recorded during the spring 1976 

 Bering Sea demersal trawl survey, in order of observed abundance, subarea 4.' 







CPUE 



Proportion of 



Cumulative 



Rank 



Taxon 



(kg/km)' 



total CPUE' 



proportion 



1 



Yellowfin sole 



40.86 



0.203 



0.203 



2 



Alaska plaice 



(23.80) 



0.118 



0.321 



3 



Unidentified sculpins 



13.43 



0.067 



0.388 



4 



Rock sole 



13.03 



0.065 



0.453 



5 



Sturgeon poacher 



3.27 



0.016 



0.469 



6 



Great sculpin 



2.60 



0.013 



0.482 



7 



Myoxocephalus spp. 



2.59 



0.013 



0.495 



8 



Longhead dab 



1.37 



0.007 



0.502 



9 



Pacific herring 



1.28 



0.006 



0.508 



10 



Walleye pollock 



1.17 



0.006 



0.514 



11 



Capelin 



1.16 



0.006 



0.520 



12 



Unidentified eelpouts 



0.37 



0.002 



0.522 



13 



Unidentified poachers 



0.35 



0.002 



0.524 



14 



Greenland turbot 



0.22 



0.001 



0.525 



15 



Unidentified snailfish 



0.19 



0.001 



0.526 



16 



Gymnocanthus spp. 



0.15 



0.001 



0.527 



17 



Starry flounder 



0.10 



0.001 



0.528 



18 



Pacific cod 



0.09 



0.001 



0.529 



19 



Pacific halibut 



0.09 



0.001 



0.530 



20 



Flathead sole 



0.08 



0.001 



0.531 



Vab 2-v/F 



(25) 



'See Figure 3. 



'Overall catch per unit effort, kg/km trawled. Total effort = 222.2 km. 

 Parentheses indicate estimates of questionable accuracy due to potential sampling 

 problems. 



'Proportion of total catch per unit effort, all fish and invertebrates combined. 

 Total CPUE = 200.93 kg/km. 



ing general patterns of species associations during the 1976 spring 

 trawl survey. The procedure identifies species relationships on the 

 basis of cooccurrence within samples and a dichotomy of group- 

 ing rules. The geometric mean of the proportion of joint occur- 

 rences, corrected for sample size, is used as an index of affinity: 



where c is the number of joint occurrences, a is the number of oc- 

 currences of species A, and b is the number of occurrences of 

 species B(b>a). If the affinity indices of species pairs are greater 

 than or equal to a specific breakpoint value (usually 0.50), then 

 the species are considered to show affinity. Grouping is based on 

 rules that include: All species within a group must show affinity 

 with all other group members, the largest possible groups are 

 formed, and no species may occur in more than one group. 



After recurrent groups were defined, intergroup relationships 

 were determined as the ratio of the number of observed species- 

 pair affinities between groups to the maximum number of possi- 

 ble connections. The occurrences of groups among stations were 

 also listed and plotted. 



Catch data from the 435 grid station trawls of the 1976 survey 

 were examined. Although a total of 264 fish and invertebrate taxa 

 was recorded at these stations, the analysis was restricted to 63 

 taxa considered to have been consistently and reliably identified 

 by all field parties during all legs of the investigations (Table 20). 

 These taxa included 45 fish taxa (18 families) representing the 

 most abundant members of the demersal fish community, and 18 

 abundant invertebrate taxa. 



Results. — The recurrent grouping procedure organized 25 taxa, 

 with one or more affinity values > 0.50, into five groups. Other 

 taxa included in the analysis did not occur frequently enough to 

 show affinity at the assigned level. Group composition and inter- 

 group relationships are shown in Figure 22. 



The 25 taxa with significant relationships accounted for 78.9% 

 (by weight) of the total catch of fish and invertebrates taken dur- 



32 



