LEWISTON — It's been another tough year for anadromous fish runs in the Snake and Columbia rivers, but coho are providing a glimmer of good news.
As of Thursday, 18,360 adult coho had been counted passing Lower Granite Dam on the Snake River. That is a modern-day record for the dam, surpassing the previous high posted in 2014. It's also pretty good for a run that was declared functionally extinct in 1985.
"I think what we are seeing now is the accumulation of about 25 years of work by the tribe," said Samuel Penney, chairman of the Nez Perce Tribe.
Coho were hit hard by overfishing and habitat destruction in the late 19th and early 20th centuries, but the big blow was the construction of the Lewiston Dam, which blocked access to spawning grounds on the Clearwater River from 1927-72.
In 1996, about a decade after coho were declared extirpated, the tribe began an effort to restore the run using hatchery stock taken from the lower Columbia River. Progress was slow but in 2014, the run surged with a return of 18,098, enough for the first tribal and nontribal fishing season in many decades.
Since then, the run — subject to conditions in the Pacific Ocean — has bounced up and down. When up, the run provides a small harvestable surplus.
Penney noted juvenile coho face the same perils en route to the ocean as chinook, steelhead and sockeye. That includes predation from non-native species like smallmouth bass and walleye, injury and stress from passing through turbines or fish bypass systems at eight federal dams, and delay caused by slackwater reservoirs. Wild runs of chinook, sockeye and steelhead are listed as threatened or endangered under the Endangered Species Act.
While proud of this year's record and the harvest opportunity it is providing for tribal and nontribal anglers, Penney sought to also provide perspective. Coho once thrived in the Snake River basin with an estimated annual return of about 200,000 fish.
"Overall, the run, compared to the historic runs, is extremely low," he said.
The tribe releases about 1.5 million coho smolts in places like Lapwai and Clear creeks on the Clearwater River and more recently in northeastern Oregon's Lostine River. If this year's run hits 20,000 adult returners, that will work out to a smolt-to-adult return rate of just 1.3%.
"We estimate we lose 50 to 70% of these juvenile fish as they migrate downstream to the ocean. That is a 500-mile journey over eight dams," Penney said. "We are happy we are having a record run but it's just a small portion of the overall historic run."
The tribe supports breaching the four lower Snake River dams as the best tool available to boost fish survival and ultimately recover the wild runs. The presence of coho and fall chinook is giving anglers alternative targets in the face of another poor return of steelhead that has seen bag limits cut throughout the Snake River basin. Tribal anglers, using a combination of gill nets and hook-and-line have harvested about 600 coho this fall, said Jack Yearout, deputy director of the harvest for the tribe's Department of Fisheries Resources Management.
"I think that would probably be one of our highest (coho) harvests, if not the highest harvest," he said. "We anticipate seeing some more harvest for a few more weeks."
As of last week, sport anglers had harvested about 360 coho in the Clearwater River and 70 on the Snake River, according to surveys conducted by the Idaho Department of Fish and Game. Anglers fishing the Grande Ronde River from the Oregon/Washington state line to the Wildcat Bridge upstream of Troy, Oregon, have caught a small number of cohos bound for the Lostine.
"Most of the people fishing down there are looking for steelhead and they are mostly catching coho, incidentally," said Kyle Bratcher, a biologist for the Oregon Department of Fish and Wildlife.
Some of the returning adults are being trapped for spawning at hatcheries. Others are being allowed to spawn in the wild.
"If you go to Lapwai Creek right now, you can see the fish chasing each other and splashing," said Becky Johnson, production director of the Nez Perce Tribe's Department of Fisheries Resources Management.
