Stock Structure of Cod

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Evaluating biological stock structure of Atlantic cod to inform fishery management

Adrienne Kovach, Natural Resources and the Environment, UNH (603-862-1603); Erik Chapman, N.H. Sea Grant and UNH Cooperative Extension (603-862-1935); Steve Cadrin, Fisheries Oceanography, UMass Dartmouth (508-910-63580; and Lisa Kerr, Gulf of Maine Research Institute (207-228-1639)

U.S. Atlantic cod (Gadus morhua) populations today are at a small fraction of their carrying capacity, and fishing communities that once depended on them are struggling for their existence. Cod stocks currently are at less than five percent of target levels in the Gulf of Maine and Georges Bank, and the latest cod stock assessment finds spawning stock biomass to be the lowest ever estimated, generating grave concern among fishermen for their livelihoods and among managers for the poor condition of cod stocks. The collapse of the Atlantic cod fishery and resulting economic hardships may be due in part to an inadequate understanding of cod population structure and dynamics and poor linkages between science and management. Biological knowledge of local populations is necessary for appropriate fisheries management and recovery of depleted stocks. Aligning management boundaries with the spatial boundaries of sub-populations increases potential for stock recovery, while misalignment of these boundaries may exacerbate declines. Identifying biologically relevant stock boundaries, therefore, is an important goal of fisheries science. Working together with fishermen and fisheries managers is also necessary to achieve consensus on applying the science to effect policy change. Kovach and her colleagues address these goals through interdisciplinary research, extension and outreach. By filling key knowledge gaps in cod stock structure and transferring these results to fisheries managers, this project will provide information necessary for reevaluating fisheries assessment and management. Synthesis of the findings with those of other regional scientists studying Atlantic cod stocks will provide a framework for developing management alternatives that recognize the importance of stock complexity in population resilience, and of spatial scale to sustainable management. Direct integration of fisheries scientists, fishermen and managers into the project through a formal working group and collaborative workshop will facilitate consensus building around management implications and ensure the results are used to improve the management of cod. Rebuilding cod stocks is vital to the economies of New England coastal communities, and to restoring a healthy ecosystem.