Maine Center for Coastal Fisheries has initiated two workshops convening experts from the United States and abroad to present up-to-date scientific information about stock structure. The first, “Exploring Fine Scale Ecology for Groundfish in the Gulf of Maine and Georges Bank” through a partnership with Gulf of Maine Research Institute and others, was held in York, Maine in 2009. The second, “Reconciling Spatial Scales and Stock Structures for Fisheries Science and Management” involved The Northeast Consortium, and was held in Portsmouth, New Hampshire in 2011. Both workshops showed that current fisheries management boundaries do not match the complex stock structure, but more importantly that cod and other groundfish have a natal homing ability – like salmon – and prefer to spawn where they hatched.
The Northeast Fishery Science Center in 2012 convened another workshop, this time focused just on Atlantic cod, “Stock Structure of Atlantic Cod in the Gulf of Maine Region.” This three-day event, held in Portsmouth, NH, brought together experts in cod tagging, morphometrics (the study of body shape), genetics, larval dispersal, and other research to make recommendations on the most likely biological structure of cod, and to provide advice for managers.
From the Executive Summary of the Workshop’s Final Report:
The Workshop agreed on the following statements on fine-scale stock structure:
- Larval retention and multi-year fidelity to local spawning sites suggest fine-scale metapopulation structure.
- Some traditional spawning groups were depleted, and have not been re-colonized by more productive groups.
- Depletion of historical spawning groups is most apparent in the eastern Gulf of Maine, the Mid-Atlantic, the ‘Plymouth Grounds,’ and recently Nantucket Shoals.
The Workshop agreed that all genetic information available from U.S. waters is not entirely congruent with current management unit boundaries. Many of the workshop participants felt that there was compelling evidence that the current management units need to be revised. However, the Workshop did not reach any conclusions on what the most appropriate management units might be.
Maine Center for Coastal Fisheries’ Downeast Groundfish Initiative focuses on providing direction to this work and building momentum for change.