Relationship between Steller sea lion diets and fish distribution in the eastern north Pacific

Relationship between Steller sea lion diets and fish distribution in the eastern north Pacific

E.L. Bredesen, A.P. Coombs, and A.W. Trites

Relationship between Steller sea lion diets and fish distribution in the eastern north PacificThis is part of Sea Lions of the World
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Description

Distributions of fish species were compared with diet information for Steller sea lions ( Eumetopias jubatus) to assess the level of correspondence between potential prey availability and sea lion feeding habits. Fish distributions were compiled as part of the Sea Around Us Project at the UBC Fisheries Centre, and were based on published distributions and habitat preferences (e.g., latitude, depth). Sea lion scat samples were collected during the 1990s from seven geographic regions from Oregon to the western and central Aleutian Islands. The frequencies of occurrence of four prevalent species (walleye pollock, Theragra chalcogramma; Pacific herring, Clupea pallasii; Pacific cod, Gadus macrocephalus; and North Pacific hake, Merluccius productus) in the Steller sea lion diet were compared to their distributions in the North Pacific Ocean. The data suggest that Steller sea lion diets broadly reflect the distributions of these major prey species. However, some of the fish species that were regionally predicted to be present in high abundance were not proportionally reflected in the Steller sea lion diet, suggesting that other factors in addition to fish abundance influence their diets.

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