Diet of Pacific Sleeper Shark, a Potential Steller Sea Lion Predator, in the North-East Pacific Ocean

Authors

M. F. Sigler, National Oceanic and Atmospheric Administration
L. B. Hulbert, National Oceanic and Atmospheric Administration
C. R. Lunsford, National Oceanic and Atmospheric Administration
N. H. Thompson, Bartlett Regional Hospital - Alaska
K. Burek, Alaska Veterinary Pathology Services
G. O'Corry-Crowe, National Oceanic and Atmospheric Administration
Amy Hirons, University of Alaska - FairbanksFollow

Document Type

Article

Publication Title

Journal of Fish Biology

ISSN

0022-1112

Publication Date

8-2006

Keywords

Diet, Predation, Sea lion, Sleeper shark

Abstract

Pacific sleeper sharks Somniosus pacificus were captured near Steller sea lion Eumetopias jubatus rookeries during the period when Steller sea lion pups are most vulnerable to Pacific sleeper shark predation (first water entrance and weaning). Analysis of stomach contents revealed that teleosts were the dominant prey in August and cephalopods were the dominant prey in May (n = 198). Marine mammals were found in 15% of stomachs regardless of season, but no Steller sea lion tissues were detected. Molecular genetic analysis identified grey whale Eschrichtius robustus and harbour seal Phoca vitulina remains in some Pacific sleeper shark stomachs. Most mammals were cetacean and at least 70% of the cetaceans were probably scavenged. Although Pacific sleeper shark and Steller sea lion ranges overlapped, so predation could potentially occur, the diet study suggested that predation on Steller sea lions is unlikely, at least when pups first enter the water or during weaning. Harbour seals were infrequent prey and may have been consumed alive. Pacific sleeper sharks consume fast-swimming prey like Pacific salmon Oncorhynchus sp., most likely live animals rather than scavenged animals. Pacific sleeper sharks appeared to be opportunistic consumers of the available prey and carrion, feeding both on the bottom and in the water column, and their diet shifted to teleosts and cetacean carrion as the fish grew larger.

DOI

10.1111/j.1095-8649.2006.01096.x

Volume

69

Issue

2

First Page

392

Last Page

405

Comments

©2006 The Fisheries Society of the British Isles (No claim to original US government works)

NSUWorks Citation

M. F. Sigler, L. B. Hulbert, C. R. Lunsford, N. H. Thompson, K. Burek, G. O'Corry-Crowe, and Amy Hirons. 2006. Diet of Pacific Sleeper Shark, a Potential Steller Sea Lion Predator, in the North-East Pacific Ocean .Journal of Fish Biology , (2) : 392 -405. https://nsuworks.nova.edu/occ_facarticles/701.