Fall chinook salmon survival and supplementation studies in the Snake River and Lower Snake River reservoirs, 1995. Annual report, January 1, 1995--December 31, 1995

摘要

Snake River fall chinook salmon (Oncorhynchus tshawytscha) are listed as threatened under the Endangered Species Act. At present, limited data exist on the migrational characteristics of Snake River subyearling fall chinook salmon, particularly concerning the proportion of migrants that survive passage through the Snake River dams and reservoirs, the effects of flows and temperatures on survival, and the percentage of subyearlings that are guided away from turbines into collection facilities and transported. As a result, operational strategies to maximize survival have been largely based on data from studies of subyearling chinook salmon that pass through lower Columbia River dams. In 1994, the National Marine Fisheries Service and the U.S. Fish and Wildlife Service began a cooperative study to investigate migrational characteristics of subyearling fall chinook salmon in the Snake River. The primary study objectives were to (1) determine the feasibility of estimating detection and passage survival probabilities of natural and hatchery subyearling fall chinook salmon released in the Snake River (2) investigate relationships. between detection and passage survival probabilities and travel time of subyearling fall chinook salmon and environmental influences such as flow volume and water temperature (3) monitor and evaluate dispersal of hatchery subyearling chinook salmon into nearshore rearing areas used by natural fish and (4) monitor and evaluate travel time to Lower Granite Dam, growth from release in the Snake River to recapture at Lower Granite Dam, ATPase levels of fish recaptured at Lower Granite Dam, and survival from release in the free-flowing Snake River to the tailrace of Lower Granite Dam.