Relative Survival of Subyearling Chinook Salmon Which Have Passed Bonneville Dam via the Spillway or the Second Powerhouse Turbines or Bypass System in 1989, with Comparisons to 1987 and 1988
Bonneville Dam, bypass, chinook, fish passage, guidance, Oncorhynchus tshawytscha, salmon, salmonids, screens, spillway, survival, traveling screen, turbines
None supplied. From introduction: Research conducted since construction of the Columbia River's Bonneville Dam Second Powerhouse in 1983 has shown that subyearling chinook salmon (Oncorhynchus tshawytscha) migrating during the summer are not effectively guided into the bypass system from turbines equipped with submersible traveling screens STS) (Gessel et. al. 1990). The structural modifications resulting from these research efforts have increased guidance for yearling salmonids migrating during the spring from 19% to as high as 74%, whereas guidance for summer migrants has remained poor (25%). The adequacy of the interim operating procedure for protecting downstream migrating salmonids at Bonneville Dam was not directly tested. There were several reasons to re-assess the passage survival at Bonneville Dam. Relative survival information specific to the passage routes tested here is critically needed for management of power production in relation to fish passage.