California’s Central Valley is home to four runs of Chinook salmon: spring, fall, late-fall, and winter. Spring-run and winter-run Chinook salmon are currently listed as threatened or endangered under the Endangered Species Act. From climate change to loss of habitat, salmon are faced with a number of threats, and one of the latest to emerge in recent years is a thiamine deficiency.
Thiamine is vitamin B1, and it is a crucial vitamin for neurons and immune systems in salmon. Evidence of a thiamine deficiency in spring-run salmon started showing up in 2020. According to Brett Harvey, Department of Water Resources (DWR) environmental program manager, salmon typically get adequate levels of thiamine from their food supply in the ocean, but for the last several years that hasn’t been happening due to changes in the ocean food web.
“As new threats emerge for salmon it’s often really difficult to come up with direct actions to help those salmon,” Harvey said.
Spring-run are unique from other runs of salmon because they return to rivers in the spring and spend the summer in cold water pools before spawning early in the fall. In the Feather River, many of these fish enter the Feather River Fish Hatchery, where they are tagged for identification and released back into the river. In 2021, DWR started injecting these fish with thiamine as they passed through the hatchery in order to decrease thiamine-related mortality of their offspring.
However, that's not all that’s happening at the Hatchery. The salmon also have their lipid levels measured as part of NOAA Fisheries’ Thermal Thresholds Project which is funded by the State Water Resources Control Board.
After the salmon receive their injections and have been measured, they are released back to the river to complete their life cycle.
“The work that we are doing to help Spring-run Chinook salmon with thiamine deficiency is just one of the many ways government agencies and partners are collaborating at what I would say are unprecedented levels to help Spring-run Chinook salmon into the future,” Harvey said.
Visit our YouTube channel for a video of DWR’s collaboration to help spring-run Chinook salmon.
Check out the Protecting California’s Salmon StoryMap to learn about DWR’s efforts to support salmon.