Effectiveness of Harvest Control Rules in Managing American Lobster Fishery in the Gulf of Maine

Abstract

Harvest control rules (HCRs) are commonly applied in managing fisheries resources. However, no HCR is explicitly defined for the fishery of American lobster Homarus americanus in the Gulf of Maine (GOM), one of the most valuable commercial fisheries in the USA. In this study we evaluated five HCRs: the “linear” HCR, the “nonlinear middle convex” HCR, the “nonlinear convex” HCR, the “nonlinear concave” HCR, and the “catch” HCR. The first four HCRs use fishing mortality curves as boundaries that could adjust the next year's target fishing mortality linearly or nonlinearly based on the stock abundance, while the fifth HCR links the catch-based boundaries to the stock abundance. A sex-specific and size-dependent operating model was developed to simulate the GOM lobster fishery managed by the above five HCRs. Four performance measures were used to quantify the effectiveness of HCRs in the lobster fishery management. For each HCR we considered both short-term and long-term management time periods and scenarios of different recruitment dynamics and natural mortality rates, as well as uncertainties in key fishery parameters. This study shows that the linear HCR can effectively maintain the fishing mortality and stock abundance around the target levels. The nonlinear concave HCR could result in a higher lowest legal biomass and a higher terminal legal biomass in a short-term management period, especially when the abundance was low. Comparing the nonlinear middle convex HCR and the “nonlinear convex” HCR, when the abundance was high, an increase of the fishing mortality would not increase the total catch but would decrease the terminal legal biomass. The fishing mortality-based HCR was more effective than the catch-based HCR in managing the GOM American lobster fishery.

Received March 14, 2011; accepted July 12, 2012

ACKNOWLEDGMENTS

This project is mainly supported by the Maine Sea Grant program (NA06OAR4170108) and the Maine Department of Marine Resources via research grants to Y. Chen and a University of Maine Provost fellowship to Y. Zhang. Zhang's time in revising this manuscript was funded by Florida International University. Data used in this study were compiled with help from the Atlantic State Marine Fisheries Commission American Lobster Stock Assessment Committee. Help from L. Jacobson, M. Kanaiwa, and G. Nesslage in the stock assessment model development are appreciated greatly. We also thank the three anonymous reviewers, Editor, and Associate Editor for their helpful, detailed, and constructive comments, which greatly improved the manuscript.