Conservation Hatchery Program

Coho salmon young of the year in Willow Creek.
Coho salmon young of the year in Willow Creek.

Pacific salmon across the west coast have faced tremendous adversity. Since the 1800s, salmon populations have been steadily declining, primarily due to severe habitat degradation. Coho salmon are currently estimated to be no more than 15% of their 1940's abundance throughout California.

The Central California Evolutionarily Significant Unit of coho is listed as endangered by the State and Federal governments. The only remaining viable wild population in this ESU is in Lagunitas Creek, in western Marin County, which supports a small fraction of historic runs. In the Russian River watershed, which historically had the largest population of coho within this ESU, coho were on the brink of extirpation by the late 1990s and restoration efforts were expanded to include a Conservation Hatchery Program, also known as a broodstock program. 

The Russian River Coho Salmon Captive Broodstock Program is a collaborative, conservation hatchery effort that is working to build a self-sustaining coho population within the watershed. Partners include the US Army Corps of Engineers, the National Oceanic and Atmospheric Administration Fisheries Service, the California Department of Fish and WildlifeSonoma Water and CA Sea Grant. Since 2001, the Broodstock Program has been breeding coho salmon from local genetic stock at the Don Clausen Fish Hatchery at Lake Sonoma and releasing them as juveniles into historic coho streams in the lower Russian River watershed.

A group of coho salmon alevin, with intact egg sacks still visible.
A group of coho salmon alevin, with intact egg sacks still visible.

Program coho salmon are carefully spawned based on a genetic matrix and reared using restoration hatchery techniques by US Army Corps of Engineers partners at the Don Clausen Fish Hatchery at Warm Springs Dam. They are then released into select tributaries to the lower Russian River as juveniles (young-of-year and smolts).

For questions about fish rearing and releases, please email Rory Taylor at

Annual coho releases from Don Clausen Fish Hatchery at Warm Springs from 2004 to 2021
Total annual releases of Conservation Hatchery Program juvenile coho salmon into Russian River streams, 2004 to 2021. Seasonal releases are ongoing.
Sarah Nossaman Pierce releasing young-of-the-year coho into Porter Creek.
CA Sea Grant biologist Sarah Nossaman Pierce releasing young-of-year coho into Porter Creek.
Since 2004, CA Sea Grant monitored wild and broodstock coho salmon in the stream environment to evaluate the efficacy of the Conservation Hatchery program and inform program strategies based on scientific findings of fish success and limiting factors. In 2023, thise field work transitioned to Sonoma Water, who continues to use techniques such as downstream migrant smolt trapping, snorkeling surveys and winter spawner surveys to monitor salmon in select lower Russian River streams at all life stages. Biologists also use Passively Integrated Transponder (PIT) tag technology to track tagged fish at channel-spanning antenna sites on the lower mainstem and several tributaries. CA Sea Grant Specialist Mariska Obedzinski continues to advise Conservation Hatchery Program partners on effective adaptive management strategies.