Bayesian forward run reconstruction for sockeye salmon fisheries in the Fraser River

Canada’s Wild Salmon Policy envisions a transition for Pacific salmon fisheries from managing for stock aggregates to managing for individual stocks. I developed a run reconstruction for Fraser River sockeye fisheries to estimate stock-specific in-river run size, harvest rate, and run timing parameters and applied it to catch and escapement data from 2003- 2009 for Summer Run stocks. The reconstruction is novel in its use of (i) mixture distributions to model arrival patterns and (ii) an ordered multinomial logit model to describe movement. Estimated stock-specific harvest rates were similar to aggregate Summer Run harvest rates with a few notable exceptions. Quesnel sockeye were consistently harvested at a lower rate than the Summer Run aggregate, whereas Stellako was typically harvested at a higher rate the aggregate, particularly at small Stellako run sizes. This model can be used to inform harvest planning and evaluate in-season monitoring efforts.