Coho salmon returns surge 10x on California’s Mendocino Coast over last decade

Story: 2026 C.E.  |  Last updated: April 28, 2026

More than 30,000 endangered coho salmon returned to the rivers of California’s Mendocino Coast during the 2024–2025 spawning season — double the previous year’s record and roughly 10 times the number seen a decade ago. Scientists, restoration workers, and tribal partners who have spent careers counting these fish in near-empty streams are describing the moment as one they never expected to witness.

At a glance

• Coho salmon recovery: Monitoring teams estimated 30,000 adult Central California Coast coho returned this season, up from around 3,000 annually just 10 years ago.
• Habitat restoration: NOAA has funded more than 100 restoration projects on the Mendocino Coast since 2000, reconnecting tributaries and rebuilding spawning habitat across the region.
• Fish passage barriers: Trout Unlimited removed a barrier on Neefus Gulch in 2024, restoring 1,600 feet of stream — and within months, salmon were spawning in areas they hadn’t accessed in 70 years.

What the rivers looked like this winter

For biologists used to surveying miles of stream and finding almost nothing, this season was disorienting in the best way.

David Ulrich, a senior scientist at Mendocino Redwood Company, said his team once surveyed two stream reaches per day on the North Fork Navarro River. Last season, they sometimes covered less than half a reach. “In the past, we’d have days where we wouldn’t see any fish,” Ulrich said. “Last year we were seeing 50 to 100 fish a day during the height of the spawning season.”

Fisheries biologist Elise Allen, surveying the Upper Noyo watershed, nearly stepped on a 70-centimeter male coho hiding under her foot. Emily Lang of the Redwood Timber Company found a large female on a redd in a channel barely 18 inches wide. “If she tried to turn sideways,” Lang said, “it would have been impossible.”

Coho also reappeared in watersheds where they had been absent for years. Usal Creek recorded its first coho since 2014. The Gualala River watershed saw them for the first time in roughly two decades. “Finding them in places where they have not been was really exciting,” said Sarah Gallagher, senior environmental scientist with the California Department of Fish and Wildlife. “I got to actually go out and see them in person and snorkel with them.”

Decades of restoration behind a single season

Central California Coast coho are listed as endangered and are considered the most at-risk subset of the coho species. Their range runs from Santa Cruz north to Punta Gorda. Getting them back has required fixing the rivers they depend on — one culvert, one logjam, one floodplain at a time.

A key strategy has been removing barriers to fish passage. Undersized road culverts block upstream access; replacing them with fish-friendly designs reopens spawning and rearing habitat that may have been cut off for generations. In 2024, Trout Unlimited removed a barrier on Neefus Gulch, a small tributary of the North Fork Navarro River, restoring 1,600 feet of stream channel. The following January, biologists found 10 coho redds in the newly accessible water — including eight above the former barrier site. “Salmon have not had the ability to spawn in this area for more than 70 years,” said Anna Halligan, director of Trout Unlimited’s North Coast Coho Project.

Restoration teams have also worked to undo damage from channel straightening and simplified waterways. When rivers run too fast and shallow, winter flows wash eggs and juveniles downstream. The Nature Conservancy, with NOAA funding, has built engineered log jams and reconnected floodplains in the Ten Mile River watershed to create slower-water refuges. “We documented juvenile coho salmon using this new floodplain habitat almost immediately after completing construction,” said Peter van de Burgt, The Nature Conservancy’s North Coast Restoration project manager. “Just days after the excavators roll out, the fish will start to swim in.”

When freshwater and ocean conditions align

Salmon live in both worlds, and both worlds have to cooperate. Coho spend about 18 months in freshwater before migrating to sea, then return as adults three years after hatching. The fish that returned this winter were born in the 2021–2022 spawning season — a year when fall rains gave their parents access to high tributaries, and when ocean conditions turned favorable for juveniles heading out to sea in 2023.

Marine survival — the share of juvenile fish that make it through their time in the ocean — was around 8% last year, compared to the typical 2% or lower. NOAA Fisheries scientists also point to conservative ocean harvest management and changes to California forest practice rules that reduce logging impacts in salmon watersheds as contributing factors.

“Recovering salmon is undeniably challenging,” said Joshua Fuller, NOAA’s Coastal California Branch Supervisor. “These numbers demonstrate that recovery is possible when management, habitat, ocean, and hydrologic conditions are aligned.”

What still lies ahead

Two record seasons in a row are cause for real optimism — but not for declaring the job done. Central California Coast coho remain endangered, and the species faces growing pressure from drought cycles and intense winter storms that can scour streams and strand fish. Monitoring teams are still collecting data through May 2026 C.E., and early counts on the North Fork Navarro already suggest a third strong year in progress.

Sustained investment in both freshwater restoration and ocean management will be needed to keep the momentum going. Funding for habitat work has historically been inconsistent, and climate variability means that the favorable ocean and hydrologic conditions that amplified this season’s returns cannot be counted on every year.

“We have conducted intensive sampling since 2009 in these watersheds,” said NOAA Marine Habitat Resource Specialist Joe Pecharich, who has worked on restoration in the region for 20 years, “and many of us never thought we’d see something like this in our lifetime.”

What the Mendocino Coast is showing is that patience, coordination, and long-term investment in salmon habitat conservation can move a species back from the edge. Over 100 restoration projects. Dozens of partner organizations. Hundreds of stream miles surveyed every two weeks. And, this winter, 30,000 fish where almost none swam before.

That is what recovery looks like when it begins.

Read more

For more on this story, see: NOAA Fisheries

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