CDFW: Coho Salmon Returning to Klamath River Basin For 1st Time in Over 60 Years
Coho salmon, a threatened species, are slowly returning to the Klamath River Basin, now that the dam blocking their passage is gone.
California Department of Fish and Wildlife officials on Nov. 22 reported the first returns of cohos to the upper Klamath River Basin in over 60 years, following removal of the former Iron Gate Dam, which was completed last month.
CDFW officials said that not since construction of Iron Gate in the early 1960s have they documented coho salmon in their historic habitat in the upper watershed. The dam was one of four hydroelectric dams built on the Klamath River between 1908 and 1962 to generate electricity.
The state agency report said that on Nov. 13, seven coho salmon entered the CDFW’s new Fall Creek Fish Hatchery in Siskiyou County. The creek was a formerly inaccessible Klamath River tributary about 7.5 miles upstream of the former dam location.
Senior environmental scientist Eric Jones, who oversees CDFW’s north state hatchery operations, said that seeing cohos successfully returning this quickly to this new habitat post-dam removed is exciting.
Of the seven coho salmon that entered the Fall Creek Fish Hatchery last week, four were male and three were female. Two were missing adipose fins, identifying them as being of hatchery origin, while the other five were identified as natural origin fish.
These returning cohos are being kept at the Fall Creek Hatchery pending genetic testing at the NOAA Southwest Fisheries Science Center laboratory in Santa Cruz. Geneticists there plan to determine which of the seven coho are the least related genetically and direct the spawning of those pairs to maximize genetic diversity.
Cohos in the Klamath Basin are listed as a threatened species under both state and federal endangered species legislation.
CDFW’s Fall Creek Fish Hatchery has an annual goal of raising 75,000 coho salmon to help restore populations in the upper Klamath River Basin post-dam removal.
A week ago, CDFW released some 270,000 yearling, fall-run Chinook salmon into Fall Creek, the last Klamath Basin hatchery release of the year, and the first release in the wake of dam removal. The year-old juvenile salmon, about four to six inches in length, were released over four days, mostly at dusk to improve survival, and allowed to swim freely out of the hatchery into Fall Creek.
Biologists said hatchery salmon released as yearlings in the fall show some of the highest rates of return as adults. They attribute this to their larger size at release and optimal fall river conditions with cool temperatures and strong flow.
These salmon are being monitored by multiple state and federal agencies, tribes and non-governmental organizations throughout the Klamath Basins, including the 420 miles of newly accessible habitat following dam removal.
