Management of the Nushagak District Sockeye Salmon Fishery: How 50 Years of Data Helps
Timothy T. Baker, Tim Sands, Fred West, Charlotte Westing, and Chuck Brazil
Abstract.—The Nushagak Management District includes the drainages of the Wood, Nushagak-Mulchatna and Igushik rivers. Sockeye salmon Oncorhynchus nerka have been commercially harvested in the rivers and adjacent marine waters since at least 1893, but it was not until the mid-1950s that consistent escapement data began to be collected for active inseason management. Escapement refers to salmon that have survived (escaped) the fisheries in Bristol Bay and have entered rivers to spawn. Managers now have 50+ years of escapement and harvest data by year class (brood tables) for most systems in Bristol Bay. Brood tables provide excellent information on spawners versus recruits, sibling relationships, and other trends that help with setting escapement goals and forecasting future returns. Catch plus escapement information was used to predict run timing and total run abundance, information useful to inseason management decision making. Comparisons of inseason escapement counts and historical escapement curves are relied on by managers making day-to-day decisions to open and close the commercial fisheries. The managers’ primary goal in managing the commercial fisheries is to ensure escapement goals are met in all three river systems while maximizing catch. The long-term catch and escapement datasets for the Nushagak District systems were used to establish stock-specific escapement goals and pre-season run-size forecasting. Daily escapement estimates, aerial surveys, test fishing, and genetic information are essential. Escapement to spawning rivers can exceed 600,000 sockeye salmon in 24 hours.