Characterizing migration and survival for juvenile Snake River sockeye salmon between the upper Salmon River basin and Lower Granite Dam

This project estimates survival and characterizes the migration of juvenile sockeye salmon between the upper Salmon River basin in central Idaho and Lower Granite Dam on the Snake River in Washington State using PIT tags and radio telemetry to determine the magnitude and locations of mortality.

Snake River sockeye salmon were listed as endangered under the Endangered Species Act (ESA) in 1991 due to extremely low adult returns. Part of the recovery strategy includes a safety-net hatchery program utilizing captive broodstock to aid in rebuilding the population. Over the previous 16-years, hatchery production of Snake River sockeye salmon has increased steadily with current production levels between 200,000 and 300,000 juveniles annually.

Estimated survival between releases into the upper Salmon River basin and Lower Granite Dam for PIT tagged juvenile Snake River sockeye salmon in the spring has been highly variable between release locations, rearing strategies, origin, and years (0.114 to 0.776). Determining where and why mortality is occurring is a critical element towards successful rebuilding and recovery of endangered Snake River sockeye salmon. We propose to utilize PIT tags and radio telemetry to characterize the migration and estimate survival for juvenile sockeye salmon between the upper Salmon River basin in central Idaho and Lower Granite Dam on the Snake River in Washington State. This projected is anticipated to be conducted each year from 2011 through 2014 in order to capture the annual variability between environmental conditions and brood years. Information gained from this study will directly contribute to actions that will play an important part in recovery of ESA-listed Snake River sockeye salmon by examining key uncertainties and filling data gaps.  Determining the causes of mortality will provide important direction to inform management actions to optimize survival for sockeye salmon.