Tag Archives: Single- vs. multi-CU models

Benchmarks of biological status for data-limited populations of Chum Salmon in southern BC

The Pacific Salmon Treaty (PST) Chum Annex requires biological benchmarks to inform the development of fishery reference points for PST related fisheries, including the lower fishery reference point for the Johnstone Strait fisheries as well as subsequent terminal fisheries. Biological benchmarks for data-limited populations have been proposed and are currently being applied to Conservation Units (CUs), or population units, of chum salmon in southern BC. The first phase of this project evaluated percentile-based benchmarks for data-limited CUs of chum salmon on the Inner South Coast of BC. Our preliminary results suggest that the 25th percentile lower benchmark is more precautionary than the stock-recruitment based lower benchmarks developed under Canada’s Wild Salmon Policy, except when CU productivity is low and historical harvest rates are high.
For 2016, we will expand our evaluation of percentile-based benchmarks to include the west coast of Vancouver Island and Fraser River, and expand our use of assessment models to include hierarchical multi-CU models. Finally, we will provide recommendations on the application of benchmarks to chum management units (through component CUs within management units) and chum salmon Genetic Units, as identified by a project funded by the PSC SEF on genetic stock identification, on the west coast of Vancouver Island and in the Fraser River within the context of the PST Chum Annex.