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Ecology and salmon related articles

Sockeye Salmon
Move Toward Recovery

by Greg Moore
Idaho Mountain Express, November 26, 2014

Study says species is gaining 'fitness'

Endangered sockeye salmon swim over spawning grounds in Redfish Lake, Idaho. The naturally spawned offspring of the fish are returning at a high enough rate to rebuild the species, a new analysis shows. Credit: Idaho Department of Fish and Game Endangered Snake River sockeye salmon are regaining the fitness of their wild ancestors, with naturally spawned juvenile sockeye migrating to the ocean and returning as adults at a much higher rate than others released from hatcheries, according to a newly published analysis.

Biologists Paul Kline of the Idaho Department of Fish and Game and Thomas Flagg of NOAA Fisheries' Northwest Fisheries Science Center reported the results in the November issue of Fisheries, the magazine of the American Fisheries Society.

The National Oceanic and Atmospheric Administration stated in a press release that biologists believe the increased return rate of sockeye spawned naturally by hatchery-produced parents is high enough for the species to eventually sustain itself in the wild again.

"This is a real American endangered species success story," said Will Stelle, administrator of NOAA Fisheries' West Coast Region. "With only a handful of remaining fish, biologists brought the best genetic science to bear and the region lent its lasting support. Now there is real potential that this species will be self-sustaining again. The sockeye didn't give up hope and neither did we."

According to a press release from NOAA, these findings demonstrate that the program to save Snake River sockeye can indeed reverse the so-called "extinction vortex," when too few individuals remain for the species to sustain itself. Some thought that Snake River sockeye had entered that vortex in the 1990s, highlighted in 1992 when the sole returning male Redfish Lake sockeye, known as "Lonesome Larry," captured national attention.

The results suggest that hatchery-produced sockeye may regain the fitness advantages they need to sustain their species in the wild much faster than had been previously estimated, the scientists reported. Biologists caution that the current results span only three years so far, but indicate that fitness -- and, in turn, survival -- can improve in as little as only one generation in the wild.

However, Idaho Rivers United Executive Director Bill Sedivy said that as laudable as the biologists' efforts have been, the sockeye are a long way from recovery, and are likely to remain so until dams are removed on the lower Snake River. He said increased spill from the dams to aid the passage of juvenile fish to the ocean would also be helpful.

"All these incredible efforts will go for naught if we don't step up our efforts to fix the migration corridor," he said.

Sedivy said recovery can't be considered to be accomplished until at least 2,500 naturally spawned adult sockeye return every year for eight consecutive years -- the time required for two generations to return. According to NOAA, about 460 naturally spawned sockeye returned to Redfish Lake this year -- the most since the program began.

NOAA Fisheries earlier this year released a proposed recovery plan for Snake River sockeye, which calls for an average of 1,000 naturally spawned sockeye returning to Redfish Lake each year, with similar targets for other lakes in Idaho's Sawtooth Valley.

The program began with 16 remaining adult sockeye -- 11 males and five females -- taken into captivity from 1991 to 1998. Through advanced aquaculture techniques, the program has retained about 95 percent of the species' remaining genetic variability, while boosting surviving offspring about 2,000 percent beyond what could be expected in the wild.

Without such advances, the scientists wrote, "extinction would have been all but certain."


Greg Moore
Sockeye Salmon Move Toward Recovery
Idaho Mountain Express, November 26, 2014

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