The California Department of Fish and Wildlife (CDFW) and the California Department of Water Resources (DWR) have announced that the Feather River Fish Hatchery in Oroville will increase its production of fall-run Chinook salmon in 2023 to approximately 9.5 million fish to combat the impacts of drought and a thiamine deficiency affecting natural spawning and in-river production.

A view of the salmon spawning operations, where personnel harvest and fertilize eggs, at the Feather River Fish Hatchery in Oroville, California. The facility was built between 1966 and 1967 by the California Department of Water Resources and operated by the Department of Fish and Wildlife, to compensate for spawning grounds lost to returning salmon and steelhead trout with the construction of Oroville Dam. Each year, roughly 9,000 to 18,000 salmon and 2,000 steelhead are spawned and raised at the hatchery. Photo taken October 9, 2014. Kelly M. Grow / California Department of Water Resources,

It is the second consecutive year the Feather River Fish Hatchery will exceed its typical production quota of 6 million fall-run Chinook salmon to help sustain California’s commercial and recreational salmon fisheries. The hatchery raised and released 8 million fall-run Chinook salmon smolts in 2022.

The hatchery, which is owned by DWR and operated by CDFW, is seeking to produce approximately 8 million fall-run Chinook salmon smolts and 1.5 million fall-run Chinook salmon fingerlings in 2023 – a 3.5 million increase over typical production goals.

“With the combination of prolonged drought, low adult returns, and a thiamine deficiency impacting in-river production, we feel it’s extremely important to maximize the actions we have available to us in the hatcheries to help sustain this extremely important population of salmon,” said CDFW Fisheries Branch Chief Jay Rowan.

The Feather River Fish Hatchery has collected 17 million fall-run Chinook salmon eggs to help meet these elevated production goals – 2 million more eggs that the hatchery’s typical egg collection target. Approximately 11,000 adult, fall-run Chinook salmon returned to the hatchery in 2022, a significant, below-average return.

Two million of the additional salmon smolts produced will be trucked to release sites in the San Pablo and San Francisco bays to maximize survival. Another 1.5 million of these additional fish will be released into the Feather River earlier in the season and at a smaller size than typical river releases. This is an experimental effort to take advantage of more favorable weather and river conditions in early spring. Twenty-five percent of the fall-run Chinook salmon produced by the Feather River Fish Hatchery in 2023 will be marked and tagged so that scientists can monitor the success of the releases.

“Releasing additional fall-run in both the Feather River and near San Francisco Bay will provide more salmon for harvest opportunities and for research,” said DWR State Water Project Assistant Deputy Director John Yarbrough. “It’s critical that when we change strategies, even during drought, we have the tools in place to understand both the impacts and the benefits of these actions. Continuing to mark these fall-run and follow them throughout their lifecycle will give us the information necessary to inform future actions.”

In the past few years, California’s Chinook salmon populations have suffered from a thiamine deficiency, which is a lack of thiamine or Vitamin B1, which can cause death in both juvenile and adult fish. The thiamine deficiency has been linked to booming anchovy populations in the ocean and adult salmon feeding almost exclusively on anchovies compared to a more diverse diet of prey species.

CDFW and DWR have been able to successfully treat both adult salmon returning to the Feather River Fish Hatchery and the fertilized eggs produced. Until there are changes in the ocean food web, thiamine deficiency will continue to be a problem for these fish. CDFW and DWR will continue to manage the Feather River Fish Hatchery to produce salmon for harvest and conservation using the best available science and management practices.