Portland, Ore. – Record returns of coho salmon to the middle and upper Columbia River this year signal the comeback of fish that 20 years ago were virtually extinct in upriver tributaries.
Reintroduction programs led by the Yakama Nation and funded in part by the Bonneville Power Administration combined with restored habitat, improved dam passage and positive ocean conditions to bring unrivaled numbers of coho back to the rivers and streams, according to recently concluded annual counts.
Ten years ago, 12 adult coho returned past Rock Island Dam near Wenatchee, Wash. This year, 19,805 passed the dam. Returns past McNary Dam near Hermiston, Ore., climbed from 4,736 coho a decade ago to 33,385 this year – by far the most since counting began at the dam in 1954.
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The rise in adult coho returning past seven or more mainstem Columbia dams to spawn this winter in upriver tributaries exceeds all expectations, said Tom Scribner, the Yakama Nation’s project leader. While most of the returning fish came from hatcheries, an expanding share comes from natural spawning that biologists hope will resurrect self-sustaining wild stocks.
The return of spawning coho to the upper Columbia reflects the success of a pioneering reintroduction strategy that no one had attempted before. The program is funded by BPA, Chelan County Public Utility District, Grant County Public Utility District and NOAA-Fisheries.
Biologists began rekindling the upriver runs in the 1990s with hatchery-bred fish from the lower Columbia, since no local coho adapted to the upper Columbia were left. Some wondered whether lower river fish, after many generations in hatcheries, could rebuild runs that would have to migrate hundreds of miles farther up the Columbia, past several major dams.
“There was a question whether it was really possible to do this so far above the dams,” said Roy Beaty, BPA’s project manager for upper Columbia coho restoration. “We really didn’t know whether the fish could swim that far.”
|Coho returns past Rock Island Dam on the Columbia River near Wenatchee, Wash. |
Irrigation diversions and development wiped out some 90 percent of native coho from the middle and upper Columbia during the late 1800s. A remnant population hung on but largely vanished by about 1980. Upriver coho did not receive protection under the Endangered Species Act, since none were left to protect.
“Coho are a kind of Rodney Dangerfield of the Columbia River anadromous fish world – they don’t get much respect,” said Nancy Weintraub, a BPA project manager who works on coho. “It’s great to see them succeed.”
BPA now funds the coho restoration program through the Columbia River Fish Accords and is completing an environmental impact statement assessing the construction and long-term operation of program facilities.
BPA is a not-for-profit federal electric utility that operates a high-voltage transmission grid comprising more than 15,000 miles of lines and associated substations in Washington, Oregon, Idaho and Montana. It also markets more than a third of the electricity consumed in the Pacific Northwest. The power is produced at 31 federal dams operated by the U.S. Army Corps of Engineers and Bureau of Reclamation and one nuclear plant in the Northwest and is sold to more than 140 Northwest utilities. BPA purchases power from seven wind projects and has more than 2,300 megawatts of wind interconnected to its transmission system