Coho salmon numbers on the rise in Sonoma

SANTA ROSA, Calif. – Field biologists funded by the U.S. Army Corps of Engineers have counted a record number of coho salmon in the downstream portions of the Russian River system in western Sonoma County, offering a glimmer of hope that recovery of the endangered silver salmon is one day possible.

Based on surveys led by California Sea Grant, there were 5,375 wild “young-of-the-year” coho in 18 of 23 tributaries surveyed between May and September. This compares with 715 wild fish counted on seven of 11 streams in 2010, and a total of only 637 wild juveniles counted collectively during the five years prior on four of nine streams.

Adult coho also appear to be reproducing in some of their historical tributaries for the first time since biologists began visually counting, tagging and trapping fish in 2005, and the fish appear to be occupying more tributaries of the river system, including some unstocked creeks.

“There is still a long road to recovery of coho salmon, but the trend is certainly promising,” said California Sea Grant’s Paul Olin, who oversees the monitoring component of the Russian River Coho Salmon Captive Broodstock Program on behalf of the U.S. Army Corps of Engineers.

“It is especially exciting to see adults returning to streams that were not stocked as part of the broodstock program,” adds California Sea Grant’s Mariska Obedzinski, manager of the monitoring program.

These signs that population recovery is possible are attributed to the Russian River Coho Salmon Captive Broodstock Program, in which wild coho from the river system are reared and spawned at Don Clausen Warm Springs Hatchery at Lake Sonoma. The offspring are released by the thousands into the river’s downstream tributaries.

The program was started in 2001 as mitigation for the construction of the dam that created Lake Sonoma. At the time, coho salmon were on the brink of vanishing from the region with about four adult spawners returning annually Biologists estimate that more than 190 adult coho may have returned to the Russian River system last year, beginning with early storms in October and peaking in December 2010. The recovery goal for the Russian River is 6,000
adult spawners annually.

“The take home message is that we have a successful program,” said Peter LaCivita, regional fisheries biologist for the U.S. Army Corps of Engineers South Pacific Division. “Our genetics management is working. Our monitoring shows us we have in-stream and returning survival, but the 190 number is just a small step. We have demonstrated the capability to do something about salmon recovery, and there is much more to be done.”

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, University of California Sea Grant Extension, U.C. Cooperative Extension, and U.S. Army Corp of Engineers, along with hundreds of cooperating landowners.




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