UC San Diego

Fisheries size limits are a fundamental harvest control rule intended to support sustainability, usually by allowing fish to reach maturity and reproduce before harvest. California relies on size limits for the management of some, but not all, recreational fisheries. For those with size limits, it is unclear whether existing control rules are sufficient to achieve sustainable levels of spawning potential. For those without size limits, the potential benefits of instituting length-based control rules for improving harvest efficiency have not been assessed. In this study, we used Length-Based Spawning Potential Ratio (LBSPR) to conduct a data-limited assessment of equilibrium stock status for a subset of high value recreational fishes and make inferences about the cumulative performance of existing management regulations. Using these model products, we then simulated stock status under alternative size limit scenarios in order to estimate the benefit of new or alternative minimum size limits on a species-by-species basis. To validate our methodology for assessing alternative size limit regulations, we leveraged data on two species of Paralabrax from before and after a recent increase in the recreational minimum size limit regulations. Our findings provide valuable insight on the status of five recreationally important yet unassessed fisheries stocks in California and identify situations where LBSPR may be successfully applied and where it may fail. Furthermore, we developed and validated a procedure for evaluating alternative minimum size limit scenarios that can easily be applied to other fisheries worldwide.