|Document Type:||Contract Report|
|Title:||Survival of subyearling Chinook salmon which have passed through the turbines, bypass system, and tailrace basin of Bonneville Dam Second Powerhouse, 1988|
|Author/Editor:||Earl M. Dawley, Lyle G. Gilbreath, Richard D. Ledgerwood, Paul J. Bentley, Benjamin P. Sandford, Michael H. Schiewe|
|Publisher:||National Marine Fisheries Service|
|Contracting Agency:||U.S. Army Corps of Engineers. Portland, Oregon|
In 1987, the National Marine Fisheries Service, in cooperation with the U.S. Army Corps of Engineers, began a multi-year study to evaluate relative survival of subyearling fall chinook salmon which have passed through the Bonneville Second Powerhouse turbines and bypass, and through the spillway. Estimates of long- and short-term survival of marked chinook salmon using various passage routes were compared to similar estimates for control groups released in the tailrace and in the river 2.5 km downstream. Long-term relative survival will be based on returns of tagged and branded adult fish to ocean fisheries, Columbia River fisheries, the Bonneville Dam Second Powerhouse fish trap, and Columbia River hatcheries.  Short-term relative survival esimates are based on recoveries of branded fish 157 km downstream from the dam at the head of the estuary at rkm 75.