Return of Columbia River coho cheers biologists

YAKIMA — Fisheries biologists in the Pacific Northwest are cheering a record return of coho salmon this year to the upper and middle Columbia River basin, where the fish were virtually wiped out 20 years ago.

Biologists began working in the 1990s to restore coho by introducing hatchery fish from the lower Columbia River, and improving dam passage and habitat in tributaries where the fish would spawn. Prospects were uncertain, largely because the lower-river fish would basically have to be trained to swim to upriver tributaries.

Those efforts, combined with improved ocean conditions, are credited with higher returns this year.

Only 12 adult coho returned past Rock Island Dam near Wenatchee 10 years ago. This year, 19,805 returned past the dam.

Though most of the returning fish are hatchery fish, returns exceeded all expectations, said Tom Scribner, project leader for the Yakama Nation Indian tribe. An increasing number of returns came from natural spawning, Scribner said, which biologists hope will resurrect self-sustaining wild coho stocks in the future.

Coho in the lower Columbia River are a threatened species, but upriver coho never received protection under the Endangered Species Act because there were no fish left to protect.

In the 1990s, the Yakama Nation, with support from other tribes, Washington state, Bonneville Power Administration and other groups, decided to try to resurrect the fish runs that were devastated by overfishing, habitat degradation due to development and sprawl, dams and agricultural diversions from rivers and streams.

About $2 million has been spent specifically on coho restoration each year since 2005. Before then, coho restoration was part of a larger hatchery program that included many species.

In central Washington’s Yakima River basin, coho were extinct by 1985.

In 2002, only about 800 adult coho returned to the Yakima River. This year, roughly 10,000 adult coho returned, with 1,800 of them wild fish, said Todd Newsome, biologist for the Yakima-Klickitat Fisheries Project, a joint project of the Yakama Nation and the Washington state Department of Fish and Wildlife.

The goal, obviously, is to get a lot more wild fish in the future, he said, but the higher numbers definitely mean a successful year.

“The test will come when the ocean conditions go down, whether we can maintain good runs,” Newsome said. “If our run goes up and down drastically like the ocean, then we’re not doing a good job.”