There are two reports here, first from California Department of Fish and Wildlife and California Department of Water Resources:
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.
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
The Golden State Salmon Association also released a statement:
GSSA Supports Additional Hatchery Salmon Production at Feather River Hatchery
Response to drought and other stressors
San Francisco — The Feather River hatchery will release millions of extra young salmon in early 2023 to help offset salmon losses caused by drought. The hatchery fertilized millions more eggs than it needed this year on the assumption the eggs might be needed by other Central Valley hatcheries due to low returns of adult fish in 2022. The other hatcheries, including Nimbus on the American River, the Mokelumne on the Mokelumne River and Coleman hatchery on Battle Creek, all ended up getting enough eggs in their own watersheds. The question immediately arose of what to do with the extra eggs. The California Dept. of Fish and Wildlife (CDFW), which runs the Feather River hatchery, recognized the value of hatching the eggs in light of drought losses.
Different ideas were discussed about how long to rear the salmon, with consideration to the limited space at the Feather River hatchery and other factors.
“The Golden State Salmon Association told CDFW it strongly supports allowing the eggs to hatch and adding them to the fishery,” said GSSA president John McManus. “The drought has decimated salmon runs in the Central Valley and we’re very grateful to CDFW for taking the initiative and helping keep the salmon industry afloat. These fish will help many people throughout California that rely on salmon to make a living or to help feed their family.”
“Salmon stocks are extremely precarious now due to both drought and the thiamine deficiency (vitamin B1) in adult salmon, which is leading to weak offspring,” said GSSA’s McManus. “Naturally spawning salmon are not doing well which means we’re relying on hatchery salmon to reboot stocks. Making more hatchery salmon costs money and we appreciate state agencies covering these costs and adding these salmon. These additional salmon will help keep the species going at levels that support a fishery, while contributing to the rebuilding of the runs in the Central Valley. GSSA appreciates the work of all the agencies involved, especially CDFW, in giving these fish a chance, and the people that rely on them some hope.”
An estimated 1.5 to 1.7 million of these fish will be released directly into the Feather River. Others will be reared a little longer and then trucked to release sites in San Pablo or San Francisco Bay in order to avoid hostile conditions expected in the river if drought persists into the spring.