The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . easternberingsea00hood Year: 1981 Northern fur seals 857 to November and 97,000 from December to May, Sanger (1974) calculated the total annual food con- sumption of fur seals in the eastern Bering Sea as 357,300 mt. Using a higher daily consumption rate and assum- ing a June-November feeding population of 551,000 and a December-May population of 69,000 animals, McAlister and Perez (1977) estimated that 387,000 mt of food were consumed by fur seals in the eastern Bering Sea. Both studies
The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . easternberingsea00hood Year: 1981 Northern fur seals 857 to November and 97,000 from December to May, Sanger (1974) calculated the total annual food con- sumption of fur seals in the eastern Bering Sea as 357,300 mt. Using a higher daily consumption rate and assum- ing a June-November feeding population of 551,000 and a December-May population of 69,000 animals, McAlister and Perez (1977) estimated that 387,000 mt of food were consumed by fur seals in the eastern Bering Sea. Both studies cite an estimate of between 318,000 and 340,000 mt attributed to A. Johnson ( Fish and Wildlife Service, personal communica- tion). The northern fur seal is a third-degree carnivore within the schematic food chain shown in Fig. 52-10 and is second only to the northern sea lion (Eume- topias jubatus) in the consumption of fish in the eastern Bering Sea (McAlister and Perez 1977). Fur seals feed almost exclusively on fish and squid. The most important prey in the Bering Sea are fishes of the families Gadidae (primarily walleye pollock) and Osmeridae (primarily capelin, Mallotus villosus), and squids of the family Gonatidae. Table 52-1 presents results of the analysis of stomach contents of seals collected pelagically in the Bering Sea by Canada and the United States from 1958 to 1974 from May through November (Kajimura et al. 1979). In this analysis an index of relative importance (IRI = percent frequency X (percent volume + percent specimens)) is calculated in an attempt to account for 171-OOW 170-OOW 169-OOW 57-50N 57-30N 57-OON k 56-30N 56-OON 55-50N \^^ 155 ib4 153 152 151 150 149 148 147 146 145 I I I I I ''~T I ] t I I I I I I 1 1 I 1 I I I I I I I I I I I I i^ SEPTEMBER SEALS PER HOUR Do f^ â 57-30N 10 or more ⢠Unit occupied for less than hour â 57-OON 326 325 324 323 322 321 320 319 318 317 £ 316 315 314 313 I ' â 312 311 310 I
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