September 28, 2020 — The following was released by the Science Center for Marine Fisheries:
Decades of strict conservation and management have led to a rebound of gray seals in the North Atlantic. Now, research from the Science Center for Marine Fisheries (SCEMFIS) is providing new insights into this population, how local fisheries interact with them, and better options to manage them.
The study, led by Drs. Doug DeMaster, Paula Moreno, Andre Punt, and John Brandon of the Independent Advisory Team for Marine Mammal Assessments, is evaluating how interactions with regional fisheries, specifically the New England sink gillnet and bottom trawl fisheries, affect the gray seal population. Revising estimates for key parameters such as abundance, levels of bycatch, and the proportion of seals crossing between the U.S. and Canada, the study is providing alternative approaches for the National Marine Fisheries Service (NMFS) to estimate Potential Biological Removal (PBR) levels. PBR determines the number of gray seals that can be removed annually by human activities without threatening the conservation status of the stock.
Preliminary results from the study find that calculations made by NMFS to determine the PBR threshold are likely too conservative. Specifically, it finds that NOAA’s estimate of gray seal productivity, a key metric in determining PBR, is too low by approximately 17 percent. It also finds that NOAA is likely being overly conservative in how it classifies at least one fishery, based on productivity, bycatch levels and assumptions regarding transboundary movements of gray seals between the U.S. and Canada.
Under the U.S. Marine Mammal Protection Act (MMPA), bycatch is strictly managed based on PBR levels, and fisheries are often required to adopt burdensome mitigation strategies as a result. Having an accurate estimate of the seal population that is interacting with commercial fisheries, and setting an appropriately precautionary estimate of PBR, is critical not just for seals, but for the fisheries that interact with them.
“With the gray seal population continuing to grow, the fishing industry is increasingly concerned about bycatch and other issues that come from seal interactions,” said Greg DiDomenico, a member of SCEMFIS’ Industry Advisory Board. “The results of this study will provide options for managing gray seals that are both consistent with federal conservation goals and may be helpful in avoiding unnecessarily burdensome regulations on fishermen.”