Summary of Abundance and Biological Data Collected During Juvenile Salmonid Monitoring on the Mainstem Klamath River Below Iron Gate Dam, California, 2014

This report summarizes results from the 2014 season of juvenile salmonid outmigrant monitoring on the mainstem Klamath River below Iron Gate Dam. Trapping occurred at three locations: below the confluence with Bogus Creek (river km 308), where Interstate 5 crosses the Klamath River (river km 294), and near the Kinsmen Creek confluence upstream of the confluence with the Scott River (river km 238). Both frame nets and rotary screw traps were used to sample juvenile salmonids and other fishes. Traps were operated beginning in mid- to late February and continued through mid-May or early June. Juvenile salmonids were enumerated daily when traps were operating and subsamples of salmonids were measured for length and weight. Non-salmonid fishes were also enumerated. Mark-recapture studies were conducted periodically at each trap site throughout the season to estimate trap efficiency. The efficiency estimates were combined with the catch data to estimate weekly and seasonal outmigration abundance of natural-origin age-0 juvenile Chinook Salmon at each trap site using a Bayesian time-stratified spline population estimation method. For the periods that traps were operated, abundance estimates of natural-origin age-0 Chinook Salmon were approximately 2.5 million at the Bogus trap site, 2.9 million at the I-5 trap site, and 5.3 million at the Kinsman trap site.