Table 10.— Food of for seals in the eastern Bering Sea, June-October 1958-74. 



Months 



Food items 



June 1 



July 



Aug. 



Sept. 



Oct. 



Fish: 













Entosphenus tridentatus 



- 



- 



X 



- 



- 



Clupea harengus pallasi 



- 



X 



4 



X 



- 



Salmonidae 



- 



X 



X 



- 



- 



Oncorhynchus spp. 



X 



- 



X 



X 



- 



O. gorbuscha 



- 



X 



- 



- 



- 



O. keta 



- 



X 



X 



- 



- 



O. nerka 



- 



X 



X 



- 



- 



Osmeridae 



X 



X 



X 



X 



- 



Mallows villosus 



1 



2 



3 



3 



1 



Thaleichthys paciflcus 



- 



X 



X 



X 



X 



Bathylagidae 



- 



X 



X 



X 



- 



Myctophidae 



- 



- 



X 



- 



- 



Lampanyctus sp. 



- 



- 



X 



- 



- 



Gadidae 



- 



X 



X 



2 



- 



Gadus macrocephalus 



- 



X 



X 



- 



- 



Theragra chalcogramma 



3 



1 



1 



1 



- 



Sebastes spp. 



- 



X 



- 



- 



- 



Anoplopoma fimbria 



- 



X 



X 



X 



- 



Hexagrammidae 



- 



X 



X 



- 



- 



Pleurogrammus monopterygius 



2 



X 



X 



X 



2 



Cottidae 



- 



X 



X 



- 



- 



Cyclopteridae 



- 



X 



X 



- 



- 



Aptocyclus ventricosus 



- 



- 



X 



- 



- 



Trichodontidae 



- 



- 



X 



- 



- 



Trichodon trichodon 



- 



- 



X 



- 



- 



Ammodytes hexapterus 



X 



X 



X 



X 



X 



Bathymasteridae 



- 



X 



X 



- 



- 



Anarchadidae 



- 



- 



X 



- 



- 



Anarhichas orienlalis 



- 



- 



X 



X 



- 



Pleuronectidae 



- 



X 



X 



X 



- 



Hippoglossoides stenolepis 



- 



- 



X 



- 



- 



Reinhardtius hippoglossoides 



- 



X 



X 



X 



- 



Unidentified 



X 



X 



X 



X 



X 



Cephalopods: 













Gonatidae 



X 



X 



X 



X 



3 



Gonatus sp. 



- 



X 



X 



X 



X 



Berryteuthis magister 



4 



4 



2 



X 



3 



Gonaiopsis borealis 



X 



3 



X 



4 



- 



Unidentified squid 



X 



X 



X 



X 



3 



Stomachs with food 



69 



924 



1,441 



375 



29 



Stomachs with trace 



17 



364 



560 



145 



3 



Stomachs without food 



74 



651 



929 



144 



14 



91% of the stations fished); second, Greenland turbot (oc- 

 curred in 78% of the stations fished); eleventh, Pacific herring 

 (occurred in 37% of the stations fished); and capelin at seven- 

 teenth place occurred in 22% of the stations fished (Pereyra et 

 al. 1976' 3 ). Principal forage species of fur seals not among the 

 trawl catches include Atka mackerel, Pacific sand lance, deep- 

 sea smelt, salmon, and sauids. 



Although we know that trawls are selective (due to the in- 

 ability to sample all substrates and incomplete sampling of the 

 water column) and that estimates of standing stocks are repre- 

 sentative only for those species which are accessible to the 

 trawl, the total fish biomass for the Bering Sea was estimated 

 at 4.4 million tons (Pereyra et al. footnote 13). Fishes of fami- 

 lies Gadidae and Pleuronectidae accounted for over 90% of 

 the Bering Sea fish catch. Based on trawl surveys, the highest 

 biomass of fish was reported at the outer shelf region, subareas 

 2 and 3 (Fig. 27), which represented 63% of the fish biomass 

 of the entire survey area. The average fish catch rate was high- 

 est in subarea 2. 



Ichthyoplankton surveys conducted in the eastern Bering 

 Sea are not as extensive as those conducted by CalCOFI off 

 California. Waldron (1981), in summarizing ichthyoplankton 

 studies conducted in the Bering Sea since 1955 by Japan, the 

 U.S.S.R., and the United States, reported that the larvae of 

 over one-third of the genera, over one-half of the families, and 

 only about one-fifth of the species of fish present as adults in 

 the Bering Sea have been collected and identified. Much of the 

 ichthyoplankton surveys in the past have centered on walleye 

 pollock. These surveys also show pollock (larvae and eggs) to 

 be the most abundant taxa accounting for more than 95% of 

 the catch (Waldron and Vinter 1978 14 ). 



In the Bering Sea, as for the waters off California, the loca- 

 tion of fur seal collection influences the importance of differ- 

 ent prey species as the principal forage food. If fur seals are 



'Numerals indicate the ranking of principal prey species based on percentage of 

 total stomach content volume. 



"Pereyra, W. T., J. E. Reeves, and R. G. Bakkala. 1976. Demersal fish and 

 shellfish resources of the eastern Bering Sea in the baseline year 1975. Processed 

 rep., 619 p. Northwest and Alaska Fish. Cent., Natl. Mar. Fish. Serv., NOAA, 

 2725 Montlake Blvd. E., Seattle, WA 98112. 



"Waldron, K. D.,andB. M. Vinter. 1978. Ichthyoplankton of the eastern Ber- 

 ing Sea. Processed rep., 88 p. Northwest and Alaska Fish. Cent., Natl. Mar. Fish. 

 Serv., NOAA, 2725 Montlake Blvd. E., Seattle, WA 98112. 



Other species of pelagic cephalopods known to inhabit the 

 Bering Sea are deepwater species and therefore are probably 

 not available to fur seals. 



Three families of fish — Salmonidae, Gadidae, and Pleuro- 

 nectidae — support the major commercial fisheries for finfish 

 in the eastern Bering Sea. Pacific salmon, of course, are im- 

 portant in the Bristol Bay salmon fishery and northward into 

 the Kuskokwim- Yukon area. The other two families make up 

 the commercially important trawl fishery resource in the east- 

 ern Bering Sea. The relative abundance of the commercially 

 important trawl or bottom fish resources in the Bering Sea is 

 relatively well-known based on commercial fish catches and 

 from U.S. research vessel surveys. The noncommercial species 

 are not as well documented. 



The rank order by frequency of occurrence (%) of the 20 

 most common fish species in the eastern Bering Sea (based on 

 trawl catches) includes four of the principal forage species of 

 fur seals. In order these are: First, walleye pollock (occurred in 



Figure 27.— Stations successfully trawled during the 1975 eastern Bering Sea base- 

 line survey (from Pereyra et al. text footnote 13). 



21 



