PNNL

Abstract

Electromyogram (EMG) radiotelemetry was used to examine the amount of energy expended by spring Chinook salmon Oncorhynchus tshawytscha migrating upstream past a Columbia River dam. Electrodes from EMG transmitters were surgically implanted in the red muscle of fish captured at Bonneville Dam and output from the tags was calibrated to defined swim speeds for each fish in a tunnel respirometer. The fish were then released below Bonneville Dam and radio-tracked as they migrated through the tailraces, fishways, and forebays of the dam. On average, the rate of aerobic energy used by spring Chinook salmon was significantly higher when they were moving through tailraces (1.27 kcal•kg-1•h-1) than when they were moving through other parts of the dam. Specifically, the rate of aerobic energy use for fish in tailraces was 14% higher than that used by fish in fishways (1.11 kcal•kg-1•h-1) and 27% higher than the rate used by fish in forebays (1.00 kcal•kg-1•h-1). Most (80%) of the aerobic energy used by fish to pass this dam was expended in the tailrace (25.5 kcal/kg), while only 18% (5.6 kcal/kg) and 2% (0.6 kcal/kg) were used in the fishways and forebays.