Bioeconomic Model Approach for a Fluctuating Fish Stock: Bioeconomic Assessment of Harvest Strategies for the Pacific Whiting Fishery

Abstract

Pacific whiting (Merluccius productus) is one of the most commercially valuable fish species in the Pacific coast groundfish fishery. Although much research has been devoted to the fishery, several biological uncertainties still exist in the Pacific whiting fishery management. This is especially true for the extreme variability in annual recruitment which causes fluctuations in stock abundance, and it is the most well known biological uncertainty for this species. Furthermore, the same stock of Pacific whiting is harvested by multiple stakeholders in the US and Canada, who have diverse motivations in harvesting/processing involve stock management. This biological uncertainty and these multiple competing interests create a difficult and complex management structure for the Pacific whiting.

This study developed a stochastic bioeconomic model of the Pacific whiting fishery in order to examine various fishing strategies from both economic and biological viewpoints. The fisheries model includes a hockey-stick recruitment function, which generates occasional extremely large recruitment, and multiple competing fishing sectors. This study applied linear harvest strategies which close the fishery when estimated biomass falls below a stipulated minimum biomass level, and set catch quotas as a fraction of the surplus of existing biomass minus the minimum biomass level (By – Bmin). To accumulate information about the variability of results from each strategy we perform 1,000 50-year simulations and then summarize the results. These summaries include: average and variance of annual harvest, average and variance of biomass, and average and variance of 50- year Net Present Values (NPV) for the fishery. This study concluded the harvest strategy with lower minimum biomass (5% of unfished biomass )and low fraction (0.2) would be desirable for three reasons; 1) maximization of catch and NPV, 2) stochastic dominance and 3) biomass conservation. (Click here for the paper)

Source: Ishimura, G. 2003. “Bioeconomic model approach for a fluctuating fish stock: bioeconomic assessment of harvest strategies for the Pacific whiting fishery.” Masters thesis, School of Marine Affairs, University of Washington.

For more information, please contact: Mark.Plummer@noaa.gov