This project, begun in 2012 by the Washington Department of Fish and Wildlife under the Sentinel Stocks Program to estimate the abundance of Chinook salmon spawners and effective breeders in the Snohomish River, continues today in partnership with the Tulalip Tribes of Washington using trans-generational genetic mark recapture (tGMR) and trans-generational rarefaction curve analysis (tRC). Additional objectives are to partition the genetic-based abundance estimate for natural spawning Chinook by origin, sex, and age, and assuming adequate data are acquired, and to develop a redd expansion calibration factor to adjust historical (or future) redd-based escapement estimates.
Funding is requested to collect and genotype subyearling offspring of the previous brood year, and to collect carcass samples from spawners in the fall. The Snohomish River basin is comprised of two Chinook salmon populations: the Skykomish River summer Chinook population (which includes Skykomish, mainstem Snohomish, and Pilchuck River) and the Snoqualmie River fall Chinook population. We expect to deliver tGMR and tRC abundance estimates for both populations for each brood year that is successfully sampled.