Prey of Steller sea lions in the Bering Sea
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One hundred and ten Steller sea lions (<i>Eumetopias jubatus</i>) that moved to the seasonal ice edge in the Bering Sea in late winter of 1981 were collected. Stomachs were examined to determine prey. Two areas were studied, one near the Russian coast in Olyutorskiy Gulf and one in US waters in the central Bering sea. Origin of the animals was probably rookeries and haulouts in the Aleutian Islands, the Commander Islands and the east coast of Asia. Only males were present. All age classes from 1 to 16 were taken but no pups of the year. Prey were found in 92 stomachs. Walleye pollock (<i>Theragra chalcogramma</i>) dominated overall, accounting for 67% of prey by weight. The second most important prey was Pacific cod (<i>Gadus macrocephalus</i>) which accounted for 15% by weight. Other important prey were squids and octopus, cephalopods; sculpins, Cottidae; Pacific herring, <i>Clupea herengus</i>; flatfishes, Pleuronectidae; other unidentified bony fishes; and Phocid seals, Phocidae. Pollock consumed by sea lions in the Bering Sea were similar in size to those consumed in the Gulf of Alaska in the 1980s but were smaller than those consumed in the Gulf of Alaska in the 1970's. Larger sea lions ate larger pollock. Pollock were important in the diets of sea lions in numerous other studies in both the Gulf of Alaska and Bering Sea. This is in marked contrast to prey remains found in scats from adult females at rookeries and haulouts during summer from the Aleutian Islands and Gulf of Alaska in 1990-1993. This could simply reflect a real shift in diet from 1981 to the 1990s but is complicated by differences in season, location and sex. Predation on other pinnipeds appears to be common by Steller sea lions.
- Biosphere conservation : for nature, wildlife, and humans
Biosphere conservation : for nature, wildlife, and humans 1(1), 33-44, 1998
Association of Wildlife and Human Society