ANALYSIS OF HARVEST STRATEGIES FOR RED KING CRAB, PARALITHODES-CAMTSCHATICUS, IN BRISTOL BAY, ALASKA

A modifiable harvest rate constrained by a minimum spawning abundance (threshold) is currently used to set the annual harvest level for Bris tol Bay red king crab, Paralithodes camtschaticus. A length-based simu lation model was constructed to evaluate effects of recruitment, natur al mortality, and handling mortality on this harvest strategy. Evaluat ion criteria included mean yield, stability of yield, harvest opportun ity, and stability of spawning stock. Optimal mature male harvest rate s were strongly negatively related to handling mortality. For any give n harvest rate, handling mortality is a key factor influencing optimal thresholds. The current harvest strategy produces a high mean yield a nd low variability in yield under low handling mortality scenarios, bu t the population is at high risk of collapse with a high handling mort ality. Given uncertainties of recruitment, natural mortality, and hand ling mortality estimates, we recommend reducing mature male harvest ra te from 20 to 15% and maximum legal male harvest rate cap from 60 to 5 0%. If handling mortality rate is greater than 30%, then we recommend increasing the threshold fi-om 6600 to 11 000 metric tons of effective spawning biomass. Our recommended harvest strategy produces a mean yi eld similar to the current harvest strategy and safeguards against rec ruitment overfishing.