California Trout Press Release
Hundreds of Coho salmon have already been observed in the newly restored habitat, up from just a few fish pre-restoration
Nonprofit research and conservation organization California Trout (CalTrout) and partners announced today they have completed a project to restore critical estuary habitat for imperiled Coho salmon, steelhead and cutthroat trout in Humboldt Bay’s watershed. CalTrout and partners widened the channel of Cochran Creek and planted native vegetation, re-creating the conditions of a natural river and floodplain at the mouth of the creek, which flows into the bay just north of Eureka. They also replaced an old tide gate with a new structure that allows more tidal water, and fish, to flow upstream. With new berms built along the new banks of the creek, the restoration provides better flood protection and better drainage for the surrounding farmland, owned by project partners John Gary and Heather Plaza, while expanding habitat and allowing the tidal creek to revert to its natural brackish state to benefit young salmon. The project may also reduce flood risk on the adjacent road.
Dozens of Coho salmon have already been observed in the newly restored habitat, up from just a few fish pre-restoration. These juvenile salmon are growing and thriving through the winter months, which are typically the most difficult months to survive through.
“The Cochran Creek restoration is a small project with a big impact, helping a federally listed population of Coho salmon while also helping the community,” said CalTrout Project Manager Matt Metheny. “This important project has fully connected Cochran Creek to Humboldt Bay for the first time in a hundred years.”
Before European settlement in the area, Cochran Creek meandered through the lowlands around Humboldt Bay, blending into a tidal marshland and providing important estuary habitat for native fish. The mixing of ocean and fresh water creates brackish (moderately salty) water that supports a highly productive community of plants, fish, and small creatures that young fish like to eat. Additionally, brackish water is essential to the salmon and steelhead lifecycle. Young salmon and steelhead hatch in fresh creek water. As they migrate downstream, they need to spend time in brackish water to give their bodies time to adjust before heading out into the ocean, where they will grow to maturity, then swim back upstream to reproduce.
Much of the natural fish habitat in the Cochran Creek watershed had been lost due to land conversion to agriculture and other uses, and the creek channel had filled in with sediment from upstream logging. An old tide gate on the creek was acting as a one-way valve to allow fresh water to flow downstream, but to block tidal salt water from flowing upstream and inundating agricultural lands.
The new tide gate allows some of the natural tidal volume (50 to 70 percent) to flow upstream, re-creating the beneficial brackish-water habitat for fish while still protecting agricultural soils from becoming contaminated by salt water. In a win-win effort for fish and farmers, project partners converted six acres of land back to aquatic and creekside habitat, while building berms to keep brackish water from flooding the landowners’ fields, and possibly the adjacent road, during king tide events. Starting from a paltry 50 feet of brackish water, the restored creek channel now contains more than six acres of tidal marsh and estuary channels. The project would not have been possible without the generous support of the landowners, who allowed those six acres to be converted from their private farmland.
Southern Oregon/Northern California Coast Coho salmon (Oncorhynchus kisutch) are critically vulnerable to extinction within the next 50 to 100 years. Their population has declined by as much as 95 percent over the past 60 years in California due to dam construction and habitat degradation from estuary alteration, agriculture and other land use practices. Northern California summer steelhead (Oncorhynchus mykiss) are also critically vulnerable to extinction by 2050, being reliant on cold water during the warmest summer months, while Northern California winter steelhead (Oncorhynchus mykiss) are in a state of long-term decline and are rated at a moderate level of concern. Humboldt Bay is home to the southernmost population of Coastal cutthroat trout (Oncorhynchus clarkii clarkii), which are at moderate risk as well, with small, fragmented populations facing multiple threats.
Funding for the Cochran Creek project came from the California Department of Fish and Wildlife’s Fisheries Restoration and Proposition 1 grant programs, the California State Coastal Conservancy, and the California Natural Resources Agency Environmental Enhancement and Mitigation Program (EEMP). Other project partners included landowners John Gary and Heather Plaza, McBain Associates, Samara Restoration, California Conservation Corps, Northern Hydrology and Engineering, Thomas Gast and Associates Environmental Associates, Pacific Earthscapes, Trinity Associates, and Nehalem Marine.
“Every bit of habitat we can restore to its natural state gives fish an outsized boost,” Metheny added. “This project is a great example of how we can restore native fish habitat in an efficient, effective way, in the Humboldt Bay watershed and up and down the North Coast, and I see many opportunities to replicate this success elsewhere. Each project brings habitat and hope for California’s native salmon, steelhead and cutthroat trout populations.”
A video about the Cochran Creek project can be seen on the CalTrout website: caltrout.org.
California Trout
California Trout partners with numerous government agencies, Tribes, and conservation groups to conduct research, habitat restoration and advocacy, to restore vibrance and abundance to California’s freshwater ecosystems and to keep them that way for years to come. Founded in 1971, CalTrout has been working for more than 50 years to protect salmon and steelhead strongholds, reconnect fish habitat, integrate fish and working lands, steward source water areas, and restore estuaries.