Anadromous fish returning to the Upper Columbia before Grand Coulee Dam’s construction: Steelhead, sockeye, spring chinook and summer/fall chinook.
June hogs: 40- to 60-pound spring chinook that migrated into Canada. They passed through U.S. territory during June, helping feed indigenous people whose food stores were depleted after winter. Some of the spring chinook spawned in the Columbia River’s headwaters at Columbia Lake, about 1,200 miles from the ocean. The spring chinook’s high fat reserves allowed the fish to make the long journey.
Dams in the way of salmon: Besides Grand Coulee, three large Canadian dams block fish passage to the Columbia River’s headwaters at Columbia Lake, including two high dams: the 574-foot Revelstoke Dam and 800-foot Mica Dam. But there’s promising habitat below those high dams, where restoration work could begin. That includes Arrow Lakes, which had a flourishing sockeye run in the past.
Donor stocks to re-establish Canadian runs could come from several sources.
Rainbow trout populations above Grand Coulee are probably descendants of steelhead that lost their ability to migrate to the ocean when the dam was built. With restored passage, some of those trout would revert to sea-run trout, or steelhead.
For sockeye, the likely donor stock is an Okanagan River sockeye run that already crosses the international border, spawning in British Columbia.
Finding donor stock for chinook salmon would be trickier. Spring chinook runs to the Columbia River tributaries of the Wenatchee, Entiat and Methow rivers are protected by the U.S. Endangered Species Act. Any efforts to reintroduce spring chinook runs to the Upper Columbia would be closely scrutinized to ensure that those fish didn’t breed with the wild chinook and dilute their gene pool.
Reintroducing a summer/fall chinook run would be easier. The Hanford Reach of the Columbia River has a robust summer/fall chinook run, and those fish are not federally protected as endangered.
Source: Canadian Columbia River
Inter-Tribal Fisheries Commission