00000nam 2200000zi 4500 9.949999 CaOODSP 20250410113725 m o d f cr mn||||||||| 250410e199011##bccab ob f000 0 eng d CaOODSP eng rda CaOODSP eng eng fre n-cn-bc pn----- x8x9 Fs97-6/1769E-PDF Fs97-6/1769E Bigg, Michael A. (Michael Andrew), 1939- author. Predation by harbour seals and sea lions on adult salmon in Comox Harbour and Cowichan Bay, British Columbia / by M.A. Bigg, G.M. Ellis, P. Cottrell and L. Milette. Nanaimo, British Columbia, Canada : Department of Fisheries and Oceans, Biological Sciences Branch, Pacific Biological Station, November 1990. ©1990 1 online resource (iv, 31 pages) : illustrations, maps. text txt rdacontent computer c rdamedia online resource cr rdacarrier Canadian technical report of fisheries and aquatic sciences, 0706-6457 ; no. 1769 Digitized edition from print [produced by Department of Fisheries and Oceans]. Includes bibliographical references (pages 15-16). "The movements, feeding behaviour and predation rate on prespawning salmon by harbour seals (Phoca vitulina) at Comox Harbour and Cowichan Bay and by sea lions (Zalophus californianus, Eumetopias jubatus) at Cowichan Bay were examined during 1989-90. Tidal variation largely governs the daily movement of harbour seals over the estuaries. Sea lions tended to remain in slightly deeper water than harbour seals and their movements were affected less by tides. Peak harbour seal abundances of 750 and 175 were recorded in Comox Harbour and Cowichan Bay respectively. A maximum of 30 sea lions were counted at Cowichan Bay. The seasonal movement of these pinnipeds into the estuaries coincided with the migration of prespawning salmon into nearby rivers. Harbour seals and sea lions fed on salmon mainly along the outer edge of the estuaries, although harbour seals also commonly fed in the lower reaches of the Puntledge River which drains into Comox Harbour. Two to four harbour seals usually preyed together upon a single salmon. A combination of cooperation and opportunism seems involved in group predation. Sea lions tended to feed individually. Based on the number of salmon seen eaten hr⁻¹ in 1989, an estimated 46% of the fall run of chinook, 4% of pinks, 8% coho and 7% chum salmon were taken by harbour seals at Comox Harbour. In Cowichan Bay an estimated 1% of coho and 1% of chum were eaten by harbour seals and 3% of coho and 3% of chum were eaten by sea lions during 1989. The fall run of chinook salmon at Comox Harbour were particularly vulnerable to predation by harbour seals due the low number of fish and their availability for predation in both the Comox Harbour estuary and the slow moving Puntledge River"--Abstract, page iii. Includes abstracts in English and French. Harbor seal Food Georgia, Strait of (B.C. and Wash.) California sea lion Food Georgia, Strait of (B.C. and Wash.) Steller's sea lion Food Georgia, Strait of (B.C. and Wash.) Pacific salmon Predators of Georgia, Strait of (B.C. and Wash.) Phoque veau-marin Alimentation Géorgie, Détroit de (C.-B. et Wash.) Otarie de Californie Alimentation Géorgie, Détroit de (C.-B. et Wash.) Otarie de Steller Alimentation Géorgie, Détroit de (C.-B. et Wash.) Saumons du Pacifique Prédateurs Géorgie, Détroit de (C.-B. et Wash.) Canada. Department of Fisheries and Oceans, issuing body. Pacific Biological Station (1972- ), issuing body. Canadian technical report of fisheries and aquatic sciences ; no. 1769. (CaOODSP)9.504449 PDF 512 KB https://publications.gc.ca/collections/collection_2025/mpo-dfo/fs97-6/Fs97-6-1769-eng.pdf