California Steelhead info from retired CA DF&W biologist Dennis Lee.
Dennis Lee
12:37 PM (9 minutes ago)
Bill;
I have read the posts and your comments in the forum regarding the” half-pounder” fishing success in the American River this late summer and early fall.
Although historically, “half-pounder” sized steelhead (fish <16 inches in length) have been observed and caught by anglers in the American River, studies in the 70’s and 80’s indicated a significant portion of the fish were strays from Coleman National Fish Hatchery, Feather River Hatchery, or naturally-produced Sacramento River steelhead. As both the wild steelhead and hatchery Sacramento River steelhead populations dramatically decreased during the past 15 to 20 years, the American River “half-pounder” fishery also diminished.
As part of an effort to replace the Nimbus Fish Hatchery (NFH) winter steelhead broodstock (the current broodstock genetically looks and performs similar to the founding Eel River winter steelhead broodstock and is in conflict with ESA concerns), two appropriate replacement broodstocks were identified, 1) Upper American River resident rainbow trout and 2) Coleman National Fish Hatchery (CNFH) Central Valley steelhead. Due to pathology concerns, studies using the Upper American River resident rainbow trout are currently unfunded and uncertain. However, two years ago Central Valley steelhead eggs were obtained from CNFH by NFH personnel and approximately 150,000 CNFH juvenile fish were reared at NFH and released in the American River along with a similar sized group of juvenile NFH winter steelhead. Although the steelhead mitigation goal is to release 430,000 juvenile fish annually, poor returns of adult fish in 2015 resulted in the hatchery having only about 150,000 juvenile NFH winter steelhead for release along with the juvenile CNFH CV steelhead.
Part of the concern is if the CNFH CV steelhead will return to NFH, can be held until sexually mature, and could provide fish for broodstock. Central Valley steelhead, along with a number of other steelhead strains have been released in the American River with poor hatchery returns. As such, the NFH winter steelhead continue to provide broodstock for the program and continue to look like and perform like the founding winter steelhead broodstock from the Eel River. Most likely this is the result of significant changes in American River streamflow quality and quantity, although evidence suggests the river prior to construction of Folsom and Nimbus dams supported a spring-run of summer steelhead.
Although it is only speculation at this point, I suggest the good American River “half-pounder” fishing this season is due to the CNFH CV steelhead releases. Unfortunately, due to poor adult steelhead returns to CNFH last year, no eggs were available for transfer to NFH this past year. It is hopeful, although not certain, CNFH CV steelhead eggs will be available this winter to allow the study and comparison to continue.
Hope this information is helpful,
Dennis
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