Sockeye Lose Ground
by Staff & Associated Press
STANLEY -- The number of sockeye salmon that made it back to their central Idaho spawning area this summer is just half of the amount that usually survive once the fish pass Lower Granite Dam in eastern Washington.
Fisheries biologists want to know why.
Typically at least 50 percent of the fish that make it past Lower Granite -- the final dam in their 900-mile journey from the Pacific Ocean -- reach the Stanley Basin. The rate was as high as 80 percent four years ago.
This year 110 adult sockeye were counted crossing Lower Granite, but only 22 made it back to the headwaters of the Salmon River. That's just 25 percent.
It compounds the already monumental losses. In 2002, 75,000 young sockeye were released from central Idaho and sent downstream to the ocean. The 22 that made it back this year are considered to be from that group, because sockeye have two-year migration cycles.
Fisheries Research Biologist Catherine Willard with the Idaho Department of Fish and Game said as many adult fish as possible will be evaluated to find out why the rate from Lower Granite has plunged.
"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.
A parasite is being considered as a possibility, but so are other factors.
Dan Baker, who manages the department's Eagle hatchery, said there are a number of theories about what is happening to the fish, ranging from disease to warming water temperatures or predators, but no solid information has been accumulated.
"It's just a long ways for them to come," Baker said. "Maybe they're dropping off because they get too tired."
The fish returning to the Sawtooth Valley were produced by the Redfish captive broodstock program, which was initiated in 1991 just before Redfish Lake sockeye salmon were placed on the endangered species list. Captive propagation is used to protect at-risk populations.
The broodstock program is a cooperative effort of the department, the Shoshone-Bannock Tribes, the University of Idaho and the National Oceanic and Atmospheric Administration-Fisheries, financed with $800,000 from the Bonneville Power Administration.
The long-range goal is to restore the return to the point that it numbers 2,000 each year.
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