Analysis of Fish Response to Flows in the 1991 Pasco Flume Experiments
attraction, avoidance behavior, behavior, bypass, Columbia River, fish attraction, fish avoidance, fish diversion, fish guidance, fish response, guidance, guidance efficiency, juvenile, salmonids, screens, sounding at barriers, swimming speeds, water velocity
This report analyzes data collected to evaluate factors affecting juvenile salmonid guidance efficiencies. The study is being conducted by Williams, Gessel, and Stanford of NMFS. The hypothesis of the study is that low fish guidance efficiency at Columbia River dams may, in part, be due to fish diving when they encounter changes in water velocities. This behavior would cause fish to move deeper in the water column allowing them to pass below the bypass screens. It is not clear though what flow conditions would produce such zones of avoidance or how fish might respond in them.