Scientists working on the recovery of endangered coho salmon in northern California appreciate success even if it comes in small doses. Field biologists from the California Department of Fish and Game (DFG) are reporting the largest number of coho returning to spawn in Sonoma County tributaries of the Russian River in more than a decade.

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. The broodstock program began 10 years ago, when wild coho salmon were rapidly vanishing from the region.

Prior to the launch of the recovery program in 2001, the number of 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 system, beginning with early storms in October and peaking in December. Promisingly, a few coho are being sighted in creeks that are not stocked, utilizing habitat beyond those tributaries in which coho are released.

“We are hopeful that coho salmon released through this program will continue to return to the Russian River system in increasing numbers and begin to establish self-sustaining populations,” says Manfred Kittel, Coho Salmon Recovery Coordinator for DFG’s Bay Delta Region. “The program is a cornerstone of coho salmon recovery efforts in central California, but the number of fish observed this year must be seen in perspective. A healthy coho population should number in the tens of thousands in California.”

Coho salmon abundance has declined dramatically statewide in the past few years. 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.

Coho salmon in central California are listed as an endangered species under both the State and Federal Endangered Species Acts. It is against the law to catch them anywhere in the state.

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 DFG, which manages the hatchery component at the Don Clausen Warm Springs Hatchery, University of California Sea Grant Extension, National Marine Fisheries Service, U.S. Army Corp of Engineers and Sonoma County Water Agency.