Project to Aid in Reintroduction of Chinooks to Historic Habitat

California Department of Fish and Wildlife
Recent droughts have decimated winter-run Chinook populations in the Sacramento River below Shasta Dam. Image via California Department of Fish and Wildlife.

A pilot project to reintroduce endangered winter-run Chinook salmon and other salmon runs to their historical habitat in the McCloud Arm of the Shasta reservoir has been funded by the California Department of Fish and Wildlife (CDFW).

The project in California’s Central Valley is designed to solve what may be the biggest challenge in reintroducing the salmon to the cold McCloud River. The $1.5 million grant for this first year of testing the collection system, leveraged by CDFW from the Wildlife Conservation Board, is going to the state’s Department of Water Resources (DWR).

The collection system consists of a debris broom, guidance net, fish trap and temperature curtain, which will be tested in the McCloud Arm of the reservoir from mid-September to mid-November after recreational activities wind down for the season. Biologists and engineers from DWR, CDFW and NOAA Fisheries are to test the system, but not release winter-run Chinook salmon into the Shasta reservoir until the collector is fully tested.

“We have a window of time to recover California’s most endangered salmon, but that time is running out,” said Barry Thom, regional administrator of NOAA Fisheries’ West Coast Region. “Saving these native fish will take science, ingenuity and lots of collaboration by all of us who want to see winter-run Chinook swim in their original habitat once again.”

CDFW Director Charlton Bonham said recent droughts have decimated winter-run Chinook populations in the Sacramento River below Shasta Dam. Climate change is expected to repeat this situation with increasing regularity. “With our state, federal and tribal partners, we can help this iconic run of Chinook salmon and increase the flexibility of California’s limited water supplies,” Bonham said.

“We acknowledge and thank DWR for their initiative on this project,” he said. “It would not have been possible without DWR’s leadership.”

The plan is for biologists and engineers to collect juvenile salmon once they hatch in the river, but before they swim into the Shasta reservoir, where the young salmon are at risk of predators and other threats. The collection system just downstream from where the river enters the reservoir would funnel colder water and the juvenile fish to a collection point. From there the fish would be transported around Shasta Dam and released into the Sacramento River to continue their migration to the ocean.

The pilot project “is just one of many efforts being implemented to address these challenges head on as we navigate unprecedented dry conditions,” said Karla Nemeth, DWR director.

The endangered salmon runs to the area date back to the 1940s, when construction of the Shasta and Keswick dams blocked winter-run Chinook salmon from reaching their original spawning grounds in the McCloud River. The salmon then began spawning in the Sacramento River below the dams, where they are exposed to summer heat. Water managers release water from the reservoir to lower river temperatures and improve survival of the eggs of this single remaining population. Drought and climate change are expected to make that increasingly difficult and ultimately impossible.

CDFW officials said the project will further the goals of California’s Water Resilience Portfolio and CDFW’s State Wildlife Action Plan, as well as addressing limiting factors specified in state and federal recovery plans.