The goal of this project is to evaluate a new genetic technology, called Parentage Based Tagging (PBT), that should provide a better tool to meet Fish & Wildlife Program objectives associated with marking hatchery stocks, conducting hatchery evaluations and reform, and enforcing salmonid fishery management measures. A large-scale evaluation of this technology was recommended by the Independent Scientific Review Panel and the Independent Scientific Advisory Board in the 2009 tagging report (ISAB/ISRP 2009).  State, tribal and federal agencies in the Snake River basin were uniquely positioned to perform a large-scale proof of concept PBT study for both steelhead and Chinook salmon because most hatchery steelhead and Chinook salmon broodstock spawned in the Snake River basin (WA, OR, and ID) have been genetically sampled since spawn year 2008; significant resources have been dedicated by BPA to the development of powerful and cost-efficient genetic marker sets for both species (Single Nucleotide Polymorphisms-SNPs); and there are sampling programs in place at Bonneville Dam, at Lower Granite Dam, and in tribal and non-tribal fisheries in the mainstem Columbia River and in the Salmon and Clearwater rivers, to sample returning hatchery adults. This project is currently creating the first generation of PBT parental genetic baselines for hatchery steelhead and Chinook salmon in the Snake basin (Ackerman et al 2011). In doing so, it effectively, permanently genetically marks ~12 million smolts, per species, per year. Through 2016, this project will demonstrate the accuracy and utility of this technology for managing wild and hatchery stocks in the basin.  Collaboration with the BPA funded project, 2008-907-00, will ensure that future genetic markers sets used in the Columbia River basin are standardized, providing unprecedented genetic tools for managing salmon and steelhead in the basin, with GSI techniques segregating adult wild runs by stock of origin, and PBT technologies identifying the stock and age of sampled hatchery fish.