Stock-Specific Distributions of Ocean Resident Chinook Salmon

Starting in 2006 Pacific Northwest commercial ocean troll fisheries for Chinook salmon have been severely restricted or closed due to low abundance of Sacramento River and Klamath River fall Chinook. In 2005, anticipating the Klamath River fishery restrictions, a collaboration of fishermen, scientists, and seafood marketers initiated Project CROOS (Collaborative Research on Oregon Ocean Salmon) to explore the potential of genetic stock identification (GSI) to provide fisheries managers with better data to manage harvest. The objective was to improve knowledge of stock distributions in the hope of avoiding weak stocks. Fishermen bar-coded each fish caught, recorded the location using GPS, collected fin clips (for GSI) and scales (for aging), along with fish length and depth caught. Data were used to map changing distributions, by stock, and to estimate local encounter rates and abundances throughout the fishery. By integrating stock-specific distribution patterns over space and time with biological and environmental data, this information will improve understanding of the ocean ecology of salmon.