California salmon are moved to a cool creek for the first time in a century, in hopes of saving it

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For 100 years, no salmon have reached the cool waters of a tributary of the Sacramento River due to dams on its lower reaches.

Now, as the river’s chinook population plummets to critical levels due to worsening drought, wildlife managers are taking unprecedented action to save them.

Last week, they began trucking adult fish, two or three at a time, to the upper reaches of Battle Creek on the border of Tehama and Shasta counties, which was part of the historic habitat of the population before the flow is dammed.

The plan is to release 300 fish to spawn there this summer when it is expected to be too hot in their usual habitat in the Central Valley.

While adults are unable to ascend the creek due to obstacles from hydroelectric facilities, baby fish spawned this summer will be able to descend the creek and its waterfalls when they are ready to migrate to the ocean, a said Peter Tira. , information officer for the California Department of Fish and Wildlife.

“It’s very high quality habitat: spring-fed streams, lots of tree cover, cold, rushing waters,” Tira said. “When we get them out of the heat, it’s much more conducive to egg laying and hatching.”

So far, state and federal wildlife officials have moved about 10 fish, which are caught in a trap at Keswick Dam at the foot of Shasta Lake.

“We are in the third year of a drought. Salmon usually only have a three-year life cycle,” Tira said. “We are about to lose an entire population of fish.”

Sacramento’s winter chinook salmon, named after the time of year the fish migrate from Golden Gate to their breeding grounds, are considered one of the nation’s most endangered species by the National Oceanic and Atmospheric Administration. . Other Chinook salmon populations that pass through at different times of the year include the fall run, which is part of the local commercial salmon fishery.

An estimated 75% of the eggs that winter wild fish laid in the Sacramento River last year were destroyed when temperatures soared in the part of the river where they spawn below Shasta Dam. That prompted the US Fish and Wildlife Service to release 525,000 baby fish from a hatchery into the river last month.

This year, the Bureau of Reclamation estimates that high river temperatures due to extremely dry conditions could kill 70% of winter run salmon eggs that spawn over the coming summer.

Wildlife managers have been trying to restore an endangered Chinook salmon population in Battle Creek for 25 years, as droughts made more frequent and severe by climate change often make their habitat too hot in the Sacramento River. In 2018, they released 200,000 baby salmon into the lower creek, fish that have since returned there as adults. But they never moved adult salmon over Eagle Canyon Dam to the North Fork of the creek.

Tara Duggan is a staff writer for the San Francisco Chronicle. Email: [email protected]: @taraduggan

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