For the 2024-2025 spawning season, monitoring teams estimate the return of more than 30,000 adult Central California Coast coho salmon to rivers on the Mendocino Coast, as NOAA Fisheries reports in its story on the record return to the Mendocino Coast. That is double the previous record of 15,000 fish in the prior season, compared to only 3,000 fish per year in some years in the past decade. The species is listed as endangered under the U.S. Endangered Species Act. NOAA Fisheries includes it as one of nine species of special concern in its Species in the Spotlight program.
According to a NOAA Fisheries report on restored habitats, rivers and streams became cut off from flood plains. Wide stretches of the watershed also lack stream structure, after large redwood trees and fallen logs were removed from creeks over the past two centuries by logging and other human activity. Young coho salmon spend one to two years in freshwater and must survive dry summers when creeks can dry into separate pools, as well as winter floods where without slow-moving side channels they risk being washed to sea.
How Streams Recovered Their Structure
For habitat restoration on the Mendocino Coast, the Office of Habitat Conservation funded $14.5 million to The Nature Conservancy and Trout Unlimited in 2023 using funds from the Infrastructure Investment and Jobs Act, according to NOAA Fisheries, for projects to be implemented over several years. One example: Trout Unlimited removed a barrier in Neefus Gulch (a tributary of the North Fork Navarro River) in 2024, restoring 1,600 feet of stream and reopening spawning habitat upstream. In 2021, the organization had already removed another barrier in Neefus Gulch. At the Dry Dock Culvert, a NOAA-funded project replaced old road culverts with a ten-foot-wide, 68-foot-long aluminum culvert. In fall 2023, a steelhead pursued by a seal made it through there, and Trout Unlimited's monitoring team found a young coho salmon above it. Project manager Anna Halligan believes fish may have had no access to habitat above that culvert for 70 to 100 years. According to Halligan, planning and design for the project took ten years.
Record Return at Ten Mile River
The recovery is especially clear at Ten Mile River: There, Central California Coast coho salmon returned in record numbers during the 2023-2024 spawning season, with approximately 5,574 fish according to NOAA Fisheries. In that same season, the river exceeded NOAA's recovery goal of 3,700 fish for the first time. According to NOAA Fisheries, removing the Central California Coast coho salmon from the endangered species list could be considered if a longer-term upward trend becomes established in multiple watersheds. The Nature Conservancy spent six years restoring winter habitat for juvenile fish on the lower Ten Mile River. Project manager Peter van de Burgt reports strong use of the restoration sites: fish there grow noticeably faster, are fitter, and have better survival chances. According to studies, only 5 percent of historic winter habitat for salmon remains available, van de Burgt notes. It typically consists of functioning wetlands and flood plains and has nearly disappeared entirely.
More Than One Factor
In winter 2023-2024, monitoring teams counted 15,000 returning coho salmon, the highest number to that date. In winter 2024-2025, this number has nearly doubled according to preliminary estimates. High Country News, citing statements from Sarah Gallagher, who leads the CDFW monitoring program, attributes the strong coho influx to a combination of restoration work, favorable ocean conditions, and a break in the multi-year drought. According to the report, the Pacific Coastal Salmon Recovery Fund of NOAA supported much of the restoration work as well as Gallagher's coho monitoring.
In Context
A 2012 monitoring study estimated the average number of adult coho salmon along the entire Mendocino Coast over three years at approximately 1,167 fish. The confidence interval of the estimate ranged from 488 to 2,068 fish. For 2008, the entire California coho population was estimated at 5,000 fish, according to The Mendocino Voice. According to the report, that represented one percent of the historic population. In winter 2024-2025, more than 30,000 coho salmon were counted in Mendocino County alone. A water specialist with the Pinoleville Pomo Nation confirmed in summer 2025 the first natural reproduction of coho salmon in the upper Russian River watershed since 1991, according to a statement from the Governor's office on December 11, 2025. Coho salmon were sighted in the Jenner Headlands Reserve on the Sonoma Coast for the first time in roughly 60 years in the week of publication of that statement. In total, the California Salmon Strategy includes 71 measures to protect salmon populations according to a statement from the Governor's office on the second progress report from CDFW. By summer 2026, 49 percent of these measures were fully completed according to the report. An additional 51 percent showed at least partial progress.
A Fraction of Historic Abundance
The recovering population remains a fraction of historic abundance: Hundreds of thousands of coho salmon once returned annually to California rivers, according to High Country News. Conservationists themselves cautioned according to The Mendocino Voice of January 24, 2026, to be careful, saying it was too early to assess the numbers of the then-current season, even if it looked like another good year.
What Could Threaten Recovery Again
The Trump administration wanted to impose deep cuts to the NOAA budget that year, according to a High Country News report of November 13, 2025. Hundreds of additional miles of streams on the North Coast need wood, the report states. And according to NOAA Fisheries, removing the entire protected unit from the endangered species list could be considered if the upward trend establishes itself longer-term in multiple watersheds.