MENDOCINO CO., 1/24/26 — After decades of decline, endangered coho salmon have returned to the coast in numbers that more than double the targets set by habitat restoration projects. In 2008, just 5,000 coho were estimated across the entire state, one percent of their historic numbers; over the winter of 2024-25, more than 30,000 were counted in Mendocino County alone, showing that recovery is possible. Conservationists say that while it’s still too early to tell what this season’s numbers might be, it’s looking promising for another good year.
Over the past decade, the Nature Conservancy, Trout Unlimited, the Mendocino County Resource Conservation District, NOAA Fisheries, California Department of Fish and Wildlife, local landowners, tribes and other partners have restored habitat across the Ten Mile, Navarro, Big River, and Noyo River watersheds. Their work has included building side channels, off-channel ponds, large wood structures, and wetlands to support juvenile coho salmon. These structures give young coho salmon safe places to hide from predators, slow-moving water to rest in during storms and abundant food, creating the kind of habitat they need to survive winter storms and grow before heading to the ocean.
Coho salmon were listed as threatened in 1996, and by 2005 were officially endangered due to decades of habitat loss from logging, erosion and sediment from road construction and upgrading, and environmental changes that left rivers and streams inhospitable for spawning. By the early 2000s, populations had plummeted statewide, and restoring the rivers and floodplains became a priority for both conservationists and local landowners, who wanted to give the species a chance to recover.
North Coast Restoration Project Manager Peter Van De Burgt, with the Nature Conservancy, said in an interview that on the Mendocino Coast, the primary driver of coho salmon’s population collapse has been human land use.
“Timber, agriculture and land clearing have affected the habitat that they need to survive their fresh water life cycles. That includes clearing hillsides, and all the sedimentation that occurs, rerouting of a lot of streams, watersheds; they’ve basically been converted into timber conveyance systems,” Van De Burgt said.
He said streams were adapted to timber harvesting and agriculture, and that led to environments that make it hard for coho to survive. Coho salmon begin their life in freshwater rivers, where they need to grow large enough to survive migrating to the ocean, then coming back to spawn before dying. Decaying salmon are an important part of nutrients for the ecosystem.
“They play this outsized role in the health of our overall ecosystem because they’re basically conveyor belts of nutrients from the river to the ocean and back, and they’re one of the only linkages that we have in nature between these ecosystems,” said Van De Burgt. “They’ve done core samples of old growth trees, and you can find salmon-derived nutrients in the middle of these ancient trees.”
He added that salmon are one of the primary sources of nitrogen for redwood forests.
Land restoration takes many steps
Creating floodplains has been a major part of the restoration projects because juvenile coho salmon need them to survive. Logging and other land use in the past left rivers running down steep inclines, so during floods, young fish were either swept out to the ocean before they were ready or sought refuge in higher floodplains, only to be stranded when the water receded too suddenly. By building inlets, gradual slopes, off-channel ponds and wetlands, restoration teams have given juvenile salmon places to rest, feed, and wait out storms.
Ellory Loughridge, North Coast Restoration Project associate with the Nature Conservancy, explained the effect of constrained rivers on juvenile coho. “It was kind of like putting your finger over a hose. It just shoots through. By making these floodplains, the water has a second area to go through, so it makes some nice little water eddies that are good for juvenile fish.”
Conservationists also added fallen logs and root wads to provide another component of essential habitat. They create deeper pools, slow sediment accumulation, offer shelter from predators, create shade during the summer and even support insect life that feeds the fish. Together, these interventions recreate the kind of complex river systems that coho salmon evolved to survive in.
When the restoration projects began, the teams had cautious expectations. The goal was to improve juvenile coho survival through the winter and gradually rebuild the population. Past efforts had focused on summer habitat, like pools created by log structures.
The reality far exceeded those hopes. In winter 2024-25, more than 30,000 coho were counted in Mendocino County, more than six times the statewide number in 2008 and double the year before, far beyond what the projects originally aimed to achieve. Not only were the fish surviving, they were thriving — they were larger, which improves their chances of surviving the ocean. Monitoring antennas showed that juvenile salmon from across the watershed were traveling to the new floodplains and wetlands to rest, hide and feed.
“I started here in 2017, and I started out doing the spawning surveys. On a busy day, you might see about ten fish, and now we have crews that will come back having seen 100 fish in a single survey. It’s just like a different world,” said Loughridge. This winter, with the count still in progress, crews are regularly seeing a hundred fish in a single visit.
Loughridge said the restoration sites are getting plenty of use, on a scale also surprising to the conservationists. “We know the fish are using them, and they’re coming from far and wide to use these restoration sites. That’s been really cool because we can see that the fish are getting full bellies and finding good habitat to survive,” she said. She also said that adult coho were using the wetland areas, which is something she hadn’t seen before.
Fist-bumps and reframing the future
When the numbers came in, Van De Burgt said the team was amazed.
“I was stoked, my coworkers were really excited. I’ve been trying to shout it from the rooftops, because I think this is one of the biggest conservation success stories we have, and people should know about that,” he said. Loughridge described a scene of excitement with the team, complete with fist-bumping.
Van De Burgt said this experience has changed the way he views his career.
“I’ve always approached this work from a scarcity mindset, like my job is to prevent extinction. If I retire, and this fish still exists in this geography, then I’ve been successful,” he said. “Now I’ve totally reframed my perspective. I’m not really focused on extinction. I think we can actually go back to recovery and get to the point where we see some semblance of historic huge runs of fish in these rivers.”
Forester Linwood Gill, who lives onsite at the Parker Ten Mile Ranch, where a large portion of restoration efforts have taken place, said the Mendocino results show what’s possible elsewhere.
“Seeing these fish come back, giving them back the habitat they need to survive… I think it’ll happen. I think it can happen anywhere people protect and steward their land,” he said.
The success on the Mendocino Coast offers hope to other watersheds across the state and the country, suggesting that with careful planning, cooperation and patience, threatened species can recover, and that conservation can be about abundance, not just preventing loss.