Endangered Coho Salmon Return to Russian River


Paul Olin
California Sea Grant Extension
E.: polin@ucsd.edu
T.: (707) 565-3449

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March 17, 2011

Mill Creek male coho salmon, December 6, 2010. Photo: California Sea Grant

March 23, 2011

Contact: Paul Olin, polin@ucsd.edu, 707-565-3449; Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

Field biologists are reporting the largest number of endangered coho salmon returning to spawn in tributaries of the Russian River in more than a decade.

Coho salmon habitat in the Russian River system

Male and female (larger fish) preparing to spawn on redd in stream. Photo: California Sea Grant

Most of these fish were released as fingerlings into the river system, as part of a captive broodstock program at Don Clausen Warm Springs Hatchery on Lake Sonoma that began 10 years ago, when wild coho salmon were rapidly vanishing from the region.

"We were very excited to observe so many adult coho return and spawn this winter," said Mariska Obedzinski, lead biologist and monitoring program manager with California Sea Grant. "A lot of people are working hard to improve conditions for coho in the Russian, and this is a hopeful sign that our efforts are starting to pay off."

Coho salmon habitat in the Russian River system

A glimmer of hope for endangered coho salmon in the Russian River, as more of the fish returned to the system in 2010-11 than in any year in the last decade. Photo: California Sea Grant


Since the launch of the recovery program in 2001, returning adult coho salmon averaged less than four per year. These low numbers were the catalyst for the Russian River Coho Salmon Captive Broodstock Program, a recovery effort in which offspring from hatchery-reared adults are released into the river system.

This year, biologists estimate that more than 190 adult coho may have returned to the Russian River watershed, beginning with early storms in October and peaking in December. Promisingly, a few coho are being sighted in un-stocked creeks, utilizing habitat beyond those tributaries in which coho are released.

“We are hopeful this trend will continue and the Russian River coho salmon population will establish self-sustaining runs,” said Paul Olin, an advisor with California Sea Grant Extension, who oversees monitoring of juvenile and adult salmon in the river system. “This program might help guide recovery efforts for many other remnant populations of coho salmon in California.”

Jennifer Hoey with AmeriCorps releases an adult coho salmon into the Russian River system

Jennifer Hoey with the Conservation Corps North Bay AmeriCorps Program releases an adult coho salmon into the Russian River system. Photo: California Sea Grant


Coho salmon abundance has declined dramatically statewide in the past few decades. Biologists believe that additional captive breeding efforts and other focused recovery measures will likely have to be instituted to prevent widespread extinction of coho salmon in Central California.

The Russian River Coho Salmon Captive Broodstock Program is a broad coalition of government agencies, scientists and private landowners dedicated to bringing back productive salmon runs. Its members include the California Department of Fish and Game, which manages the hatchery component at the Don Clausen Warm Springs Hatchery, National Marine Fisheries Service, Sonoma County Water Agency, California Sea Grant Extension, U.C. Cooperative Extension, and U.S. Army Corps of Engineers, along with hundreds of cooperating landowners.