Harvest Strategies for Multispecies Fisheries Under Catch Constraints

Current groundfish species in the Bering Sea, Alaska, are managed under strict annual quotas. However, there are strong bycatch regulations in place that compromise the ability of the fleet to catch the entire quota. As a consequence, single species population forecasting might not be very accurate if the multispecies nature of the fishery is ignored. In addition, uncertainty in environmental fluctuation and fishermen behavior can affect the accuracy of population forecasting and bias the effect of management actions. Management strategy evaluation (MSE) is a computer simulation method that consists in modelling both the fish population and the management cycle (stock assessment and decision making) of a fishery to evaluate the performance of the management actions. This procedure has been shown to be very important as it can caution the user about the potential undesired effect of their proposed management actions (e.g. unwanted reduction in quotas). In this study, a MSE was developed to test 1) how the inclusion of a multispecies catch tradeoff affect the short- to long-term performance of the model (e.g. catches, discounted revenue) compared to traditional single species model, and 2) how these models perform in the presence of environmental and fishermen behavioral uncertainty.