Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 7600
Title: Detection of PIT-tagged juvenile salmonids in the Columbia River estuary using pair-trawls, 2008
Author/Editor: Robert J. Magie, Matthew S. Morris, Richard D. Ledgerwood, Amy Cook, Benjamin P. Sandford, Gene M. Matthews
Publication Year: 2010
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Walla Walla, Washington
Contract Number: 56ABNF100030
Pages: 82
Date: August 2010
Keywords: salmon monitoring,trawl,PIT detection

 In 2008, we continued a study using a surface pair-trawl fitted with a detection system to detect juvenile Pacific salmonids <i>Oncorhynchus</i> spp. implanted with passive integrated transponder (PIT) tags. We operated the trawl in the upper Columbia River estuary between river kilometer (rkm) 61 and 83, sampling for a total of 976 h between 7 March and 20 August and for an additional 60 h between 29 September and 30 October. We detected 16,563 PIT-tagged juvenile anadromous salmonids of various species, runs, and rear types. Among the annual total detections, 16% were wild fish and 81% were hatchery-reared, with the remaining 3% composed of fish from unknown origins. Of all fish detected, 61% were Chinook salmon, 36% were steelhead, and 3% were other salmonid species or unknown species.

Theme: Recovery and rebuilding of marine and coastal species
Foci: Develop methods to use physiological, biological and behavioral information to predict population-level processes.