|Document Type:||Contract Report|
|Title:||Evaluation of juvenile fall chinook salmon passage through the McNary Dam juvenile fish bypass system to identify areas of delay|
|Author/Editor:||Gordon A. Axel, Richard W. Zabel, Benjamin P. Sandford, Douglas B. Dey|
|Publisher:||National Marine Fisheries Service|
|Contracting Agency:||U.S. Army Corps of Engineers. Walla Walla, Washington|
In 2001, we completed the second year of a study to evaluate travel times of juvenile subyearling chinook salmon Oncorynchus tshawytscha in the bypass system at McNary Dam. The first year of study indicated a delay associated with passage through the juvenile fish bypass system: median residence time within the Unit 8A gatewell was 2.8 h. During 2001, 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. A total of 262 tagged fish were released into the gatewells of three turbine units and monitored as they traversed the bypass system.
All 261 radio-tagged fish were detected as they passed through the bypass system and exited the separator. Median residence time was 8.6 h in gatewell 8A, 2.6 h in gatewell 10A, and 3.7 h in gatewell 13A. Gatewell residence accounted for 90-98% of total travel time through the juvenile bypass system.