Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 5466
Title: Evaluation of subyearling fall chinook salmon passage in the McNary Dam juvenile fish bypass facility, 2000
Author/Editor: Gordon A. Axel, Douglas B. Dey
Publication Year: 2001
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Walla Walla, Washington
Pages: 9
Date: 2001

In 2000, we completed the second year of a study to estimate post-detection bypass survival of juvenile subyearling fall chinook salmon at McNary Dam.  The first year of study indicated a delay associated with passage through the juvenile fish bypass system.  During 2000, radiotelemetry receivers were deployed to determine areas of delay within the gatewell, collection channel, and separator.

River-run subyearling chinook salmon were collected and radio tagged at the McNary Dam juvenile fish collection facility, released into a gatewell, and monitored as they passed through the bypass system.

Of the 114 radio-tagged fish released, 113 (99.1%) exited the separator.  Median residence time in the gatewell was 2.8 hours, accounting for 96% of bypass delay.  Median residence times in the collection channel and separator were 3.8 and 2.2 minutes, respectively.