From NOAA Fisheries:
Last winter, Central California Coast coho salmon returned to Mendocino Coast rivers in the highest numbers since monitoring began. The overall numbers remain low compared to the species’ past abundance, but NOAA scientists are excited by the results.
Last winter, endangered Central California Coast coho salmon (CCC coho) returned to Mendocino Coast rivers and streams in the highest numbers since monitoring began 16 years ago. Monitoring led by the California Department of Fish and Wildlife to track their population status estimated more than 15,000 adult CCC coho returned to spawn during the 2023–24 season. The Ten Mile and Noyo rivers exceeded recovery targets set by NOAA for delisting CCC coho under the Endangered Species Act, and the Big and Garcia rivers experienced record returns.
While the overall numbers remain low compared to the species’ past abundance, NOAA scientists are excited by the results.
“I remember in the 1990s monitoring streams where water temperatures were too hot for CCC coho and lacking in structure, and I thought they would never come back in my lifetime,” says NOAA San Joaquin River Branch Chief Jonathan Ambrose. “I’ve been at NOAA Fisheries for 25 years, and we’ve changed the trajectory for CCC coho salmon. A lot of people think it’s too late—it’s too hard to bring back endangered species. This is a prime example of why it’s not too late or too hard.”
CCC coho salmon, a NOAA Species in the Spotlight, still have a long way to go before the species can be delisted or removed from the endangered species list. CCC coho are an evolutionary significant unit (ESU), meaning a genetically distinct segment of the coho salmon species. The recovery targets set by NOAA indicate a level where CCC coho salmon are considered stable and no longer at risk of going extinct. NOAA’s recovery targets must be consistently met in multiple watersheds before scientists can consider changing the status of the CCC coho salmon evolutionary significant unit.
“Long-term status and trend population monitoring is a crucial component of recovery to help determine when a species can be delisted and to inform management actions,” says Sarah Gallagher, Senior Environmental Scientist with the California Department of Fish and Wildlife. “Last spawning season’s positive news affirms the importance of our work and the need to continue investing in monitoring and restoration.”
CCC coho originate from rivers south of Punta Gorda in Northern California. They represent the southernmost and most endangered subset of the coho salmon species.
In the past, hundreds of thousands of CCC coho salmon returned to California rivers to spawn. They provided a feast for people, wildlife, and redwood forests, which grew to towering heights with marine-derived nutrients. However, overfishing, climate change, and habitat degradation from logging, road building, and other practices pushed coho salmon to the brink of extinction.
By the time the species was listed under the ESA in 1996, CCC coho had seemingly vanished from many rivers and streams. Since then, NOAA has invested $82.2 million in restoration work and monitoring of CCC coho salmon in the Mendocino Rivers.
How Monitoring Works
Monitoring numbers are based on spawning surveys, which count the number of salmon nests in random, spatially-balanced sample sites. The sites are located throughout the 500 miles of CCC coho salmon spawning habitat on Mendocino Coast. Teams visit each site every 2 weeks throughout the spawning season. Counts are expanded out to make population estimates for each watershed. They also count adult and juvenile fish at other monitoring stations to help calibrate the accuracy of the surveys.
Since 2000, NOAA Fisheries’s Pacific Coastal Salmon Recovery Fund has provided CDFW $61.5 million to monitor fish populations and award restoration grants to state partners in Mendocino. The CDFW, Pacific States Marine Fisheries Commission, Redwood Timber Company, and Mendocino Redwood Company conduct the monitoring.
In addition to helping to determine the status of CCC coho salmon populations, monitoring also informs restoration practitioners about which techniques are working well.
“One cool finding we’ve seen through our monitoring is that fish will use our newly restored sites instantly and travel an incredibly long distance to use good off-channel floodplain habitat,” says Peter van de Burgt, North Coast Restoration Project Manager for The Nature Conservancy. “Monitoring creates this feedback loop between our science and our restoration program. We’re constantly learning from each phase of restoration and incorporating those lessons learned into our next project.” NOAA funds effectiveness monitoring for The Nature Conservancy (TNC) and Trout Unlimited’s (TU) Mendocino Coast restoration projects in addition to the monitoring funds awarded to CDFW.
What Contributed to the Increase in Salmon Numbers
Many complex factors influence CCC coho numbers, including ocean conditions and California’s increasingly erratic cycles of drought and heavy rains. Commercial and recreational fishing for CCC coho salmon has been closed for nearly 20 years, possibly contributing to better numbers.
Scientists working with NOAA and our partner organizations believe that the restoration of freshwater habitats and collaboration with landowners to improve land management practices have played a significant role. “I feel the new numbers show that all of the investments we’ve been making are working,” says NOAA Fisheries Biologist and CCC Coho Recovery Coordinator Erin Seghesio. “NOAA and our partners can recover this species and heal the rivers from their historic damage.”
Since 1996, NOAA, partners, timber companies, and local landowners have built strong, effective partnerships that have successfully:
- Implemented more than 400 habitat restoration projects in Mendocino Coast watersheds using continuously refined, science-based restoration techniques
- Significantly increased restoration funding in recent years through the Bipartisan Infrastructure Law, allowing NOAA partners to carry out multiple large-scale projects quickly
- Streamlined permitting and planning processes to increase the pace of restoration
- Helped change California forest practice rules, minimizing the impacts of logging in salmon habitat
- Built relationships with timber companies and other landowners to reduce harmful land management practices
“There’s this culture and community invested in implementing restoration on the Mendocino Coast and recovering CCC coho salmon,” says van de Burgt. “We’re just one part of that community, but it’s enabled all of us to do our part, and it all adds up to a big change.”
A Long-Term Investment in Restoration
Since 2000, NOAA’s Office of Habitat Conservation has spent $20.6 million to support more than 100 restoration projects on the Mendocino Coast. In 2012, NOAA published the CCC Coho Salmon Recovery Plan, which details the types of habitat restoration necessary for the species to rebound.
Over the years, restoration work has been designed to be reshaped by natural stream processes. Healthy rivers and streams naturally meander and spread out or contract depending on seasonal flows. For restoration work to produce long-term benefits, projects must be designed to provide salmon habitat in a dynamic ecosystem.
“Just like it’s good to have a diverse economic portfolio, we want coho to have access to a diversity of habitats so they can respond to whatever climate event is occurring year-to-year,” says Anna Halligan, North Coast Coho Project Director for Trout Unlimited. “In the big water years, we want fish to disperse across the watershed, so we must ensure there are no passage barriers to restrict their migration. Conversely, we need to find ways to enhance habitat lower in the watershed and conserve stream flow during drought.”
“Restoration has been a constant learning process,” says NOAA Marine Habitat Resource Specialist Sarah Pierce. “There’s been a lot of information sharing across all collaborators. We’ve been growing the knowledge base for 20 years and are applying effective techniques to our current projects funded through the Bipartisan Infrastructure Law.”
Scaling Up Restoration and Cutting Green Tape
In 2023, NOAA awarded TNC and TU $14.5 million through the Bipartisan Infrastructure Law for large-scale restoration projects on the Ten Mile, Big, Garcia, Noyo, and Navarro watersheds. TU began construction last year on one of seven barrier removal projects in the Big River watershed. Staff have already observed juvenile CCC coho salmon and steelhead using reopened habitat. In spring 2025, TNC will begin building its biggest-ever restoration project on the Mendocino Coast. Construction crews will restore about 40 acres of floodplains and two miles of stream habitat on the Ten Mile River.
“The funding allows us to cover multiple watersheds and complete full project cycles, from systematic planning to determine the most limiting factors to coho survival, through design and construction of restoration actions to address these factors,” says van de Burgt. “It will also directly lead to dozens of on-the-ground restoration projects over the coming years.”
NOAA, CDFW, and other agencies have simplified their project permitting processes to allow partners to break ground on construction faster. Permits that once took a year to process can now be arranged in a matter of weeks. NOAA has also spent years streamlining restoration planning. NOAA and CDFW use the Salmon Habitat Restoration Priorities process to identify salmon strongholds and bring partners and landowners together to develop mutually beneficial projects.
While much work remains to recover CCC coho salmon, NOAA, and our partners remain committed to their survival. “I’ve seen tremendous positive changes within Mendocino County and across the CCC coho salmon landscape in the 15-plus years since coming on with the NOAA Restoration Center,” says Pecharich. “I’m confident that if we continue to work together, we will see a continued positive trend of coho salmon success throughout their geography.”
