
Three separate strains of fish – the Eel River strain of American River steelhead, the Coleman Hatchery steelhead strain, and Central Valley hatchery steelhead of undetermined origin – are returning to the American River this year, as evidenced in a trip that I made to the Nimbus Fish Hatchery on January 30.
The hatchery staff sorted through the fish as I watched them and took photos. The only fish the staff spawned during the season or put in the holding ponds for spawning over the next couple of weeks were the Eel River strain fish, characterized by their big silvery sides and slender bullet shapes.
The staff released both Eel River strain and the Central Valley fish back into the river. Meanwhile, they killed the Coleman strain fish, obtained from Battle Creek at Coleman National Fish hatchery, as part of a study to see how the fish fare in the American.
The reason for the current study of the Coleman fish goes back to 2008, when NOAA Fisheries issued a biological opinion requiring that fishery managers look at appropriate local Central Valley stocks for possible introduction into the American River, in order to reduce straying.
The biological opinion also urged fishery managers to explore reintroducing steelhead and salmon above rim dams into the headwaters where the fish used to spawn, including on the American River below Nimbus.
Before Folsom Dam, salmon and steelhead ascended into North, Middle, and South Forks of the American to spawn. As late as 1944, 1945, and 1946, the Department documented spring run Chinook salmon ascending the fish ladder at the old Folsom Powerhouse, according to Dr. Robert Titus, fishery scientist, in a presentation for the Save the American River Association in December 2013.
Jay Rowan, Acting Senior Hatchery Supervisor for CDFW's North Central Region, emphasized, “We have NO plans to get rid of the current Eel River steelhead strain. This is an exploratory phase only, since they may.