Dear Colleagues, I would like to share with you a new publication on Steller and California sea lion consumption of Pacific salmon in northwest Washington. The study reports on the frequency and overall consumption estimates by species and size class of salmon by sea lions based on analysis of prey remains from scat samples. The manuscript is freely available at (PDF) Consumption of Pacific salmon (Oncorhynchus spp.) by California sea lions (Zalophus californianus) and Steller sea lions (Eumetopias jubatus) in northwest Washington during 2010–2013 (researchgate.net) <https://www.researchgate.net/publication/360739376_Consumption_of_Pacific_salmon_Oncorhynchus_spp_by_California_sea_lions_Zalophus_californianus_and_Steller_sea_lions_Eumetopias_jubatus_in_northwest_Washington_during_2010-2013> .
Abstract: Pacific salmon (Oncorhynchus spp.) are important to the ecology, economy, and cultures of the Pacific Northwest. Many populations of Pacific salmon in the Pacific Northwest are declining because of poor marine survival. We evaluated the role of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions as predators of Pacific salmon. Roughly, half of the 1330 metric tons (t) of Pacific salmon eaten by Steller sea lions per year and of the 1220 t of Pacific salmon eaten by California sea lions per year in northwest Washington during 2010–2013 were coho salmon (O. kisutch). The response of Steller and California sea lions to the large run of pink salmon (O. gorbuscha) in 2011 was less than expected. Sea lions of these species rarely ate large (roughly ≥50 cm in total length) Chinook salmon (O. tshawytscha), indicating that they have limited direct competition for prey with the southern resident distinct population segment of killer whales (Orcinus orca). Combined, California and Steller sea lions in northwest Washington consumed a mass of coho salmon similar to that landed by commercial fisheries in Washington State. More work on modeling the effect of the predation by California and Steller sea lions on salmon populations, particularly for coho salmon, is needed to better evaluate the conservation and productivity of Pacific salmon. -- Respectfully, Jonathan Scordino Marine Mammal Biologist Makah Fisheries Management (360) 645-3176
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