Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 4500
Title: Condition and gatewell retention time of yearling and subyearling chinook salmon guided from modified turbine intakes at Bonneville Dam Second Powerhouse, 2008-2009
Author/Editor: Lyle G. Gilbreath, Benjamin P. Sandford, Michael H. Gessel, Dean A. Brege, D. Ballinger
Publication Year: 2012
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Portland, Oregon
Date: 2012

In 2008 and 2009, we evaluated mortality, descaling, and passage time for juvenile Chinook salmon through the bypass system at Bonneville Dam Second Powerhouse. 
Fish were fin clipped or tagged, released at specific points within the system, and recaptured at the juvenile fish monitoring facility. 
Separate test series were conducted for Spring Creek National Fish Hatchery subyearling Chinook, river run yearling Chinook, and river run subyearling Chinook salmon.
Treatment groups were released to Gatewells 12A and 14A in 2008 and to the A intake of Turbine Unit 14 in both years. 
Reference groups were released to the juvenile bypass collection channel in both years. 

We compared mortality, descaling, and passage time between treatment groups released during different turbine operating conditions. 
These conditions were the lower, lower middle, middle, middle upper, and upper 1% of peak turbine efficiency. 
Target turbine unit flows (kcfs) ranged from 11.7 for lower 1%, 13.5 for lower middle 1%, 14.7 for middle-1%, 16.3 for middle upper 1%, and 17.8 for upper 1% operations. 
Release group sizes were planned to allow us to detect a minimum additive difference of 3% in mortality and descaling between treatments (alpha = 0.05, beta = 0.2).

Theme: Recovery, Rebuilding and Sustainability of Marine and Anadromous Species
Foci: Describe the relationship among human activities and species stock status, recovery, rebuilding and sustainability.
Maximize effectiveness and minimize impacts of artificial propagation in recovery, rebuilding and stock sustainability