California Department of Fish and Wildlife officials say that the drought having a significant impact on the state’s water supply is also putting the state’s salmon at serious risk. To that end, California’s Water Resources and Fish and Wildlife departments are collaborating through shared projects, funding and research efforts to identify challenges facing salmon and to promote salmon health and survival.
These projects include restoring critical habitat for salmon and other fish species, improving salmon migration corridors to and from the ocean, and increasing monitoring efforts to better track fish populations and devise new strategies to improve their status.
In April, DWR and CDFW staff began work to remove vegetation from a key migratory path for adult spring-run Chinook salmon in the Sutter Bypass that runs parallel to the Sacramento River southwest of the Sutter Buttes. Waters are warmer in the bypass because of the severe drought and changing climate, and that has resulted in extensive overgrowth of aquatic vegetation that impedes adult salmon migration.
Further up the Sacramento River, returning salmon will find a new side channel with gravel suitable for spawning and riverbank vegetation to help reduce water temperatures. The warming climate and dry conditions are leading to increased river temperatures that can have fatal consequences for salmon.
Also underway along two tributaries of the Sacramento River in Tehama County is an enhanced research and monitoring project for spring-run juvenile salmon in Mill and Deer creeks by CDFW biologists under funding by DWR.
A major multi-agency effort is underway to assist migration of winter- and spring-run adults and juveniles around dams on the Upper Sacramento River and tributaries so they can access historical spawning and rearing habitat that has been inaccessible for decades since dam construction.
State, federal, and university scientists are working to uncover new information and develop new actions to support and protect California’s salmon. For the last two years, scientists observed that many baby salmon are dying before they hatch, or shortly thereafter, and discovered the cause was a thiamine deficiency in their parents resulting from a shift in the ocean food web, a phenomenon recently observed in a number of fish populations around the globe.
More about collaborative projects protecting salmon populations is available at water.ca.gov, which is highlighting these efforts and more. Additional projects are expected to be featured this summer.