Monitoring for Effects of Hatchery-Produced Sockeye Salmon on Natural-Origin Sockeye Salmon in the Lake Washington Basin: An Overview of the Adaptive Management Program

In the 1930s, efforts to establish a major sockeye salmon run in the Lake Washington basin were initiated by planting sockeye into some of the lake’s tributaries.  These efforts were successful as total returns have ranged up to 700,000 adults since the late 1960s.  In 1991, a small hatchery was established on the lake’s largest tributary, the Cedar River, to help support a sockeye salmon population that has been recently declining precipitously, provide fish for harvest, and to mitigate for a dam that blocked spawning access to 12 miles of the Cedar River.  In 2011, the hatchery expanded to full capacity and an Adaptive Management Plan (AMP) was initiated to guide the program.  The objectives of the AMP are to do no harm to the natural-origin sockeye salmon run while providing harvest.  The AMP focuses on evaluating 6 key uncertainties throughout the life cycle of sockeye salmon.  A key underpinning of the AMP is that hatchery-origin returns of sockeye salmon over the long term and on average will contribute no more than 50 percent of the overall sockeye return to the Cedar River.  The framework for the monitoring plan is presented along with some initial monitoring results.