In June 2025, a juvenile coho salmon swam through a tributary of a Northern California river that had gone without the species for more than thirty years. Dakota Perez Gonzalez, a water specialist with the Pinoleville Pomo Nation, spotted the fish while snorkeling in an isolated pool of Ackerman Creek in Mendocino County. It was the first documented natural reproduction of coho salmon in the upper Russian River watershed since 1991. What sounds like a local footnote is evidence that a decades-long ecosystem restoration project is working.
Down to Two Places
Coho salmon (Oncorhynchus kisutch) were widespread in Northern California until the 1990s. Dams blocked migration routes to spawning grounds; clear-cutting removed the riparian vegetation that keeps water temperatures cool enough for reproduction. By 1991 the species had vanished entirely from the upper watershed. By the late 1990s, the entire Central California Coast coho population survived in only two locations: the Russian River in Sonoma and Mendocino counties, and Scott Creek near Santa Cruz. The species was close to regional extinction.
In 2001, the California Department of Fish and Wildlife launched a captive breeding program at the Don Clausen Fish Hatchery at Lake Sonoma, using locally sourced genetic stock. The immediate goal was not restoration but survival: preserve genetic diversity until the habitat could be sufficiently rehabilitated. When the Russian River Coho Water Resources Partnership program began in 2009, roughly 20 adults were returning to spawn. That was the entire wild population.
What Restoration Has Achieved
Since then, the numbers have changed dramatically. In Willow Creek, researchers counted more than 100 coho redds (nests) during the 2024/2025 season. A camera at the Mirabel Fish Ladder recorded 90 adult fish migrating upstream in a single season. From 20 animals, hundreds have returned.
Restoration efforts worked on several levels simultaneously. The Mill Creek Fish Passage Project reopened 11.2 miles of previously blocked waterway by removing a dam and renaturalizing the channel. The Pinoleville Pomo Nation invested in water quality monitoring and habitat restoration specifically in Ackerman Creek, where the juveniles were found. State agencies, tribal communities and conservation organizations worked in coordination.
The 2025 discovery was qualitatively different from the population growth seen in prior years. The fish returning until recently were hatchery-raised. The juveniles in Ackerman Creek were wild-reproduced. That means the river now meets the ecological conditions under which salmon can survive and reproduce without human supplementation. That is the difference between a species-preservation program and a functioning ecosystem.
The Role of the Pinoleville Pomo Nation
Perez Gonzalez and his team recovered two of the juvenile salmon during their snorkel survey and transported them to the Warm Springs Fish Hatchery to secure them for the breeding program. From the same drying pool, they also rescued three Chinook salmon, 146 steelhead trout and hundreds of other fish species.
The Pinoleville Pomo Nation combines traditional ecological knowledge with modern hydrology in its work. For Perez Gonzalez, the find is not a scientific success alone but confirmation of an approach: conservation without the communities who have lived in an ecosystem for centuries is less effective. Many restoration projects on the West Coast have faltered by excluding local knowledge.
What Remains to Be Done
NOAA Fisheries has set a long-term recovery target of 10,100 adult coho salmon returning annually to the Russian River watershed. Current numbers remain well below that threshold. The Russian River is the largest waterway in the current range of the endangered Central California Coast coho. What succeeds here is watched as a model for salmon recovery across the entire West Coast.
The confirmation of natural reproduction in Ackerman Creek shows the goal is no longer only on paper. A river that had no self-reproducing coho population since 1991 has one again. The next challenge is scaling that recovery before further drought years reduce water flow and push the still-fragile populations back toward the edge.