Table 11. — Summary of average calch per unil fishing effort of major laxonomic groups in the Bering Sea, 1976 spring trawl survey.' 





Mean CPUE 



























for total 



Proportion 





Mean CPUE by subarea (kg/km) ! 







Proportion of total catch by subarea 



> 





survey area 

 (kg/km) 



of total 























Taxa 



catch 



1 



2 



3 



4 



Slope 



1 



2 



3 



4 



Slope 



Gadidae 



(39.16) 



0.137 



3.0 



(136.7) 



(41.1) 



1.3 



(99.4) 



0.007 



0.305 



0.277 



0.006 



0.445 



Pleuronectidae 



(141.41) 



0.493 



(283.7) 



(205.2) 



34.2 



(79.6) 



68.0 



0.687 



0.458 



0.230 



0.396 



0.3O4 



Cottidae 



18.12 



0.063 



27.4 



22.3 



6.2 



18.8 



4.0 



0.066 



0.050 



0.042 



0.094 



0.018 



Zoarcidae 



1.90 



0.007 



0.1 



3.3 



4.7 



0.4 



1.2 



< 0.001 



0.007 



0.032 



0.002 



0.005 



Rajidae 



1.31 



0.005 



— 



2.5 



1.8 



lr 



13.6 



— 



0.006 



0.012 



< 0.001 



0.061 



Agonidae 



3.01 



0.011 



5.5 



2.6 



0.4 



3.6 



0.1 



0.013 



0.006 



0.003 



0.018 



< 0.001 



Other fish 



3.57 



0.012 



4.3 



2.0 



4.6 



2.7 



8.4 



0.010 



0.0O4 



0.031 



0.013 



0.038 



Total fish 



(208.48) 



0.727 



(324.0) 



(374.6) 



(93.0) 



(106.4) 



(194.7) 



0.784 



0.836 



0.626 



0.530 



0.871 



Porifera 



1.94 



0.007 



6.1 



1.4 



0.1 



0.6 



0.1 



0.015 



0.003 



< 0.001 



0.003 



< 0.001 



Coelenterata 



2.45 



0.009 



3.8 



2.7 



2.1 



1.5 



1.6 



0.009 



0.006 



0.014 



0.007 



0.007 



Mollusca 



4.48 



0.016 



2.6 



2.8 



5.9 



5.9 



4.8 



0.006 



0.006 



0.040 



0.029 



0.021 



Gastropoda 



4.14 



0.0i4 



2.4 



2.2 



5.7 



5.7 



1.5 



0.006 



0.005 



0.038 



0.028 



0.007 



Pelecypoda 



0.07 



< 0.001 



0.1 



tr 



tr 



0.1 



tr 



< 0.001 



< 0.001 



< 0.001 



< 0.001 



< 0.001 



Cephalopoda 



0.27 



< 0.001 



tr 



0.6 



0.2 



tr 



3.3 



< 0.001 



0.001 



0.001 



< 0.001 



0.015 



Crustacea 



48.66 



0.170 



45.4 



61.3 



38.8 



54.8 



13.2 



0.110 



0.137 



0.261 



0.273 



0.059 



Total crabs 



48.51 



0.169 



45.3 



61.1 



38.5 



54.7 



12.5 



0.110 



0.136 



0.259 



0.272 



0.056 



Chionoecetes spp. 



38.78 



0.135 



24.4 



50.7 



32.4 



50.6 



11.8 



0.059 



0.113 



0.218 



0.252 



0.053 



Paralithodes spp. 



6.62 



0.023 



17.4 



9.0 



2.4 



0.5 



0.1 



0.042 



0.020 



0.016 



0.002 



< 0.001 



Total shrimp 



0.11 



< 0.001 



tr 



0.1 



0.3 



tr 



0.7 



<0.0Ol 



< 0.001 



0.002 



< 0.001 



0.003 



Other Crustacea 



0.04 



< 0.001 



0.1 



0.1 



tr 



0.1 



tr 



< 0.001 



< 0.00 1 



< 0.001 



< 0.001 



< 0.001 



Echinodermata 



16.60 



0.058 



25.7 



4.9 



8.2 



23.6 



9.1 



0.062 



0.011 



0.055 



0.117 



0.041 



Asteroidea 



13.14 



0.046 



23.0 



0.9 



2.4 



22.1 



2.3 



0.056 



0.002 



0.016 



0.110 



0.010 



Echinoidea 



0.28 



< 0.001 



0.9 



0.2 



tr 



tr 



0.2 



0.002 



< 0.00 1 



< 0.001 



< 0.001 



0.001 



Ophiuroidea 



2.68 



0.009 



0.6 



3.8 



5.8 



1.5 



0.6 



0.001 



0.008 



0.039 



0.007 



0.003 



Holothuroidea 



0.51 



0.002 



1.3 



tr 



tr 



0.1 



5.9 



0.003 



< 0.001 



< 0.001 



< 0.001 



0.026 



Ascidiacea 



3.00 



0.010 



5.2 



tr 



tr 



5.7 



tr 



0.013 



< 0.001 



< 0.001 



0.028 



< 0.001 



Other invertebrates 



1.00 



0.003 



0.4 



0.2 



0.5 



2.4 



tr 



0.001 



< 0.001 



0.003 



0.012 



< 0.001 



Total invertebrates 



78.13 



0.273 



89.2 



73.3 



55.6 



94.5 



28.8 



0.216 



0.164 



0.374 



0.470 



0.129 



Total catch 



(286.61) 



1.000 



(413.2) 



(447.9) 



(148.6) 



(200.9) 



(223.5) 



1.000 



1.000 



1.000 



1.000 



1.000 



1 Parentheses indicate estimates of questionable accuracy due to potential sampling problems. 

 1 tr = CPUE <0.05 kg/km. 

 1 See Figure 3. 



tatively identified. In general, sculpins were ubiquitous through- 

 out the entire survey area, at moderate levels of abundance (Table 

 1 1 , Fig. 16). Catches of sculpins were highest in central regions of 

 the continental shelf, ranging up to 450 kg/km trawled. 



Zoarcidae feelpouts). — Zoarcids were relatively rare, with six 

 tentatively identified species representing only 0.7% of the overall 

 mean total catch (Table 11). The distribution of eelpouts was 

 essentially restricted to the outer continental shelf (depths >75 

 m), with regions of high apparent density northwest and southeast 

 of the Pribilof Islands (Fig. 17). 



Rajidae (skates). — Five species of skates were tentatively iden- 

 tified during the survey, although the reliability of identifications 

 was questionable due to the poor taxonomic descriptions available 

 for Bering Sea rajids. The distribution of skates was restricted to 

 the outer continental shelf and slope, with occurrences primarily 

 at bottom depths > 100 m (Fig. 18). Abundances were highest in 

 the slope subarea with catch rates ranging up to 156 kg/km, 

 although relatively low throughout most of the observed range 

 (Table 11). 



Agonidae (poachers). — Agonids occurred throughout most of 

 the study area (Fig. 19), with highest apparent abundance in 

 subareas 1, 2, and 4N and S (Table 11). Five species were ten- 

 tatively identified, with the sturgeon poacher, Agonus 

 acipenserinus, accounting for 77% of the overall total agonid 



catch. Although the overall average abundance of poachers was 

 relatively low, individual catches ranged up to 201 kg/km trawled. 



Invertebrate catches. — Invertebrates accounted for 27% of the 



weight of the overall mean total catch, with highest abundance 

 being observed in subareas 1, 2, and 4N and S (Table 11). In 

 general, invertebrate abundance was highest directly east of the 

 Pribilof Islands, and north of Unimak Island (Fig. 20). A total of 

 169 invertebrate taxa were recorded during the survey. Five prin- 

 cipal invertebrate groups accounted for 74.9% of the overall total 

 invertebrate catch (by weight): Chionoecetes opilio (snow crab, 

 36.5%); asteroids (starfish, 16.8%); C. bairdi (snow crab, 9.3%); 

 Paralithodes camtschatica (red king crab, 7.2%); and gastropods 

 (snails, 5.1%). 



Twenty-seven species of snails were identified during the 

 survey. Highest abundance was observed in subareas 3 and 4 

 along the central shelf (Table 11, Fig. 21). 



Relative Importance of Individual Species 



Frequency of occurrence. — Occurrences of the 20 most com- 

 mon fish taxa are summarized in Table 13. Only 14 fish taxa oc- 

 curred in more than 130 (30%) of the 435 grid station trawls; 19 

 fish taxa occurred only once. The percentage of occurrences of 

 individual species varied considerably between geographical sub- 

 divisions of the study area, reflecting differences in distributional 

 range and density distribution. 



21 



