Sockeye Salmon Return to Idaho

Sockeye salmon have returned to the Sawtooth Valley but numbers have biologists concerned. Fisheries Research Biologist Catherine Willard reported that at least 110 adult sockeye salmon had been counted passing Lower Granite Dam, the last dam in the sockeyes' 1,800 mile round-trip journey back to Idaho. To date, six sockeye salmon have been trapped at fish weirs operated by the Idaho Department of Fish and Game in the Sawtooth Valley near Stanley. An additional 16 adults are holding below the Sawtooth Fish Hatchery weir but have not yet entered the trap. Last year 3 adult sockeye salmon returned to the Sawtooth Valley. The fish returning to the Sawtooth Valley were produced by the Redfish Lake captive broodstock program, initiated in 1991 just before Redfish Lake sockeye salmon were placed on the federal endangered species list. Captive propagation is used to protect at-risk populations. Rearing fish in the hatchery from the egg stage to adulthood maximizes survival and reproduction. This is a cooperative effort with Fish and Game, the Shoshone-Bannock Tribes, the University of Idaho, and the National Oceanic and Atmospheric Administration-Fisheries. The program is funded by Bonneville Power Administration as mitigation for the federal Columbia River Power System. In 2002, an estimated 75,092 hatchery and naturally produced sockeye salmon smolts left the Sawtooth Valley en route to the ocean. Adults returning this year are most likely from that group. Each year returning adults are taken into the captive broodstock breeding program or are released to spawn naturally in Sawtooth Valley lakes. Willard said the percentage of adults passing Lower Granite Dam that reach the Sawtooth Valley is lower than in previous years. Biologists refer to this as the "conversion" of adults from one point to the next in their journey. Typically, 50 percent of sockeye salmon adults that pass Lower Granite Dam make it to the Sawtooth Valley. Willard said the low conversion of adults from Lower Granite Dam is a concern for the program's cooperators. "We need to examine as many sockeye salmon adults as we can this year to try to better understand what is causing the low conversion," she said. If the sockeye salmon holding below the weir do not swim into the Sawtooth Fish Hatchery weir by mid-September, Fish and Game and program cooperators are planning to capture the adult sockeye salmon by seining or hooking so they can determine if factors such as disease might be affecting the adults' migration.