UC Delivers

Russian River coho salmon recovery from near extinction

The Issue

Russian River coho salmon recovery from near extinction
Juvenile coho salmon in Mill Creek
Some still remember watching bright red salmon each year splashing around in the small Russian River tributary creeks between Thanksgiving and early February. Once numbering in the thousands, today coho salmon in the Russian River and its tributaries are on the verge of local extinction. To prevent this from happening, the California Department of Fish and Game (DFG), NOAA Fisheries, the Army Corp of Engineers, the Sonoma County Water Agency, Sonoma County UC Cooperative Extension and Sea Grant teamed up in 2001 to create the Russian River Coho Salmon Captive Broodstock Program. Under this program, juvenile coho were collected from coho streams within the Russian River watershed by DFG, and subsequently raised to maturity and spawned at Don Clausen Warm Springs Hatchery at Lake Sonoma. In 2004, DFG began releasing the offspring of these captive-bred wild fish into Russian River tributaries that historically held runs of coho salmon. The goal of this program is to restore self-sustaining runs of coho salmon to multiple tributaries of the Russian River, and in doing so, create a balance where the river’s water can sustain both the coho salmon and the residential and agricultural uses that rely on it.

What Has ANR Done?

UCCE staff document the growth and survival of released fish as they spend time in the stream, migrate to the ocean, and ultimately return to their natal streams to spawn as adults. UCCE fish biologists measure fish populations in release streams and operate traps from March through June to estimate the number of smolts swimming out to the ocean. Instream research tracks fish and documents their use of specific seasonal habitats. From December through February, resistance board weir traps are operated to capture and document returning adults. The results are then used to inform future program decisions about fish releases and habitat restoration that will increase the likelihood of salmon recovery in the Russian River. Every year since the first fish were released in 2004, UCCE has documented successful oversummer and overwinter survival and outmigration of juvenile coho smolts. To learn more about the coho recovery program and for information on identifying coho and distinguishing them from steelhead and Chinook salmon, see UCCE’s Web site, http://groups.ucanr.org/RRCSCBP.

The Payoff

Coho salmon successfully spawning in Russian River tributaries

Once on the brink of localized extinction, adult returns from the ocean and successful spawning have been documented each year since 2006. Recovery of this endangered species is critically important both for the fish, and for the people in the watershed who also rely on the river’s water. As release numbers increase, we anticipate a corresponding increase in returns, especially with the good ocean conditions for smolt survival we have observed in recent years. Data are being used to refine stocking protocols, and incorporate the release of acclimated coho smolts as part of the program. The number of fingerlings stocked in 2006, 2007 and 2008 was 42,838, 71,159 and 70,069 respectively. Outmigrating smolt numbers in 2006, 2007 and 2008 were 2,711, 7,146 and 10,914 respectively. We are on track to accomplish our goal and see these fish return in sufficient numbers to establish self-sustaining runs in this historic habitat.


Supporting Unit:

Sonoma County Cooperative Extension and the Sea Grant Extension Program
Paul G. Olin, David Lewis, Mariska Obedzinski, (707) 565-2621, pgolin@ucdavis.edu, djllewis@ucdavis.edu, mobedzinski@ucdavis.edu