Annual Report: Trinity River Basin Salmon and Steelhead Monitoring Project: Chinook and Coho Salmon and Fall-Run Steelhead Run-Size Estimates Using Mark-Recapture Methods, 2013-2014 Season

The California Department of Fish and Wildlife's Trinity River Project conducted tagging and recapture operations from June 2013 through March 2014 to produce run-size, angler harvest, and spawner escapement estimates of spring-run (spring Chinook) and fall-run Chinook salmon [fall Chinook (Oncorhynchus tshawytscha)], coho salmon (O. kisutch), and fall steelhead (O. mykiss) in the Trinity River basin. This information is produced for the Trinity River Restoration Program (TRRP) to help evaluate progress toward program objectives outlined in the Integrated Assessment Plan (TRRP, 2009) Utilizing a Petersen mark-recapture methodology, we estimate a run-size of 8,961 spring Chinook migrated into the Trinity River basin upstream of Junction City weir. Using tags returned by anglers we estimate 254 spring Chinook were harvested, yielding an escapement of 8,707 fish. The 2013 run of spring Chinook was comprised of an estimated 2,669 naturally-produced adults and 146 jacks and 6,011 hatchery-produced adults and 135 hatchery-produced jacks. The post-harvest escapement of 2,591 naturally-produced adult spring Chinook was 43.2% of the TRRP goal of 6,000 spring Chinook. An estimated run-size of 36,989 fall Chinook migrated past Willow Creek weir (WCW), of which an estimated 880 were harvested by anglers, yielding and escapement of 36,109 fish. The 2013 run of fall Chinook was comprised of an estimated 17,104 naturally-produced adult and 6,514 jack salmon and 13,168 hatchery-produced adults and 6,514 hatchery-produced jacks. The post-harvest escapement of 16,689 naturally-produced adult fall Chinook was 27% of the 62,000 fish TRRP goal. The coho run-size in the Trinity above Willow Creek was estimated at 21,906 fish, with no coho reported as harvested, leaving all 21,906 fish for potential spawning escapement. The coho escapement was comprised of an estimated 4,305 naturally-produced adult and 152 jack coho and 14,782 hatchery-produced adult and 2,667 hatchery-produced jacks.