Storm runoff to aid salmon migration

There’s at least one immediate benefit from the most recent storms that swept through California: Wildlife officials will temporarily stop transporting hatchery salmon by truck, and instead release those fish at the hatcheries following usual practice.

The U.S. Fish and Wildlife Service announced Thursday that Coleman National Hatchery near Red Bluff will pause its trucking operation to take advantage of storm runoff in Battle Creek, which flows through the hatchery, and the Sacramento River. They will release the next batch of about 4.5 million young fall-run Chinook salmon at the hatchery instead, starting Friday.

The California Department of Fish and Wildlife will also release about 1 million endangered spring-run Chinook salmon into the Feather River from its hatchery near Oroville. It had planned to haul these fish by truck.

Releasing salmon at their hatcheries is the preferred practice because it allows the fish to “imprint” on that location so they can find their way back from the ocean in three to four years to breed as adults.

Both agencies jointly launched an unprecedented emergency program last week to haul juvenile salmon in climate-controlled tanker trucks downstream to Rio Vista, on the banks of the Sacramento River. There, the fish are held in the river in net pens for two to three hours, to acclimate to the new water chemistry, before being released to continue migrating to the ocean. About 2.5 million salmon have been hauled by truck from Coleman hatchery so far.

The goal was to protect the salmon from poor water conditions along their migratory route in the Sacramento River caused by the ongoing California drought. Storms over the past week temporarily improved flows, allowing the trucking operation to be paused. Officials said, however, that they may resume trucking if river conditions again become unfavorable.

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