Salmon seen in Northern California river for first time in a century

Researchers with the U.S. Forest Service and California’s Department of Fish and Wildlife take part in a pilot study to return salmon runs to the North Yuba River. Tim Walton, CDFW

Several months after the start of a pilot program aiming to restore salmon runs in California’s Sierra County, Chinook salmon can be found in the North Yuba River “for the first time in close to a century,” the California Department of Fish and Wildlife announced on Thursday.

The salmon are a result of a project studying the return of spring-run Chinook salmon to their native spawning habitat in the Sierra Nevada, the department said. The eggs that the fish hatched from were deposited in October along a 12-mile stretch of gravel riverbed in the North Yuba River east of Downieville in an effort to mimic the spawning behaviors of wild salmon.

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Young fish were first seen on Feb. 11 in a rotary screw trap installed several miles downstream from where the eggs were implanted, according to CDFW. The fish are being trucked downstream to the lower Yuba River, where they will then continue their migration to the ocean.

“This is habitat that salmon haven’t been into for a long time so we have very little data to understand how salmon will respond,” Colin Purdy, fisheries environmental program manager for the Fish and Wildlife Department’s North Central Region, said in the agency’s news release. “By injecting these eggs into multiple locations in the North Yuba River, we’re going to be able to look at how long it [takes] for eggs to hatch and turn into yolk sac fry, how do they rear, how fast do they grow, when and where do they rear as juvenile salmon in this new habitat. So there are a number of different things that we’re going to be able to learn from this.”

Chinook salmon have historically spawned in the North Yuba River, but haven’t been seen in its waters since the construction of the Englebright Dam east of Yuba City in 1941. The project aimed at returning them to the river is one of several salmon restoration initiatives taking place in California, including the historic dam removal project that recently took place along the Klamath River.

Spring-run Chinook salmon are vulnerable to “scorching” temperatures present in the Central Valley, according to the department. Since there are now dams present along many of the rivers and tributaries where the fish traditionally return after growing to adulthood in the ocean, they often become “trapped” on the hot valley floor, unable to reach colder waters upstream.

There are no plans for any dam removals along the Yuba River, according to the department, meaning any salmon that spawn in the North Yuba River need to be trucked downstream past the dams to continue their migration to the Pacific. A similar process is being used to reintroduce winter-run salmon on the McCloud River in Shasta and Siskiyou counties.