Abundance Estimates for Stillaguamish River Chinook Salmon Using Trans-generational Genetic Mark Recapture

The primary objective of this trans-generational genetic mark-recapture (tGMR) project is to: 1) estimate the abundance of Chinook salmon spawners and effective breeders in the Stillaguamish River above the smolt trap site using genetic abundance methods. The secondary objectives of this study are to: 2) estimate the natural spawning Chinook salmon abundance by origin (hatchery or natural), sex and age, and 3) estimate a redd expansion calibration factor from historic redd-based escapement estimates and possible future redd counts. The data collected for this project also provide a genetic baseline for these population estimates, a genetic (parentage-based) estimate of the proportion of hatchery-origin spawners, and an estimate of relative reproductive success of hatchery spawners, because carcasses are classified by origin. Genetic sampling will be conducted during the fall spawning period, and smolt trapping will be conducted during the following spring.