OCEAN SPRINGS, MS / ACCESSWIRE / September 28, 2020 / 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."
The study concluded that, given existing evidence for transboundary seal movement between the U.S. and Canada, the abundance estimate used in calculating PBR and the estimate of bycatch used to classify fisheries should take into account both regions. While the stock exists on both sides of the U.S.-Canadian border, fisheries managers in the U.S. had previously treated the U.S. portion of the stock as a distinct population, with no exchange between the U.S. and Canadian seals. According to the study, regulators have a reasonable option for filling the data gaps on Canadian bycatch in order to get a more complete understanding of stock size and how interactions with commercial fisheries may be affecting the stock.
The study will continue its work over the next few months, where the team will build on its work by examining potential biases in survey methods, as well as produce recommendations for further research.
SCEMFIS is part of the National Science Foundation's Industry-University Cooperative Research Centers Program, supporting fisheries research improving the future of finfish and shellfish productivity, from the Gulf of Mexico to the Gulf of Maine.
SCEMFIS utilizes academic and fisheries resources to address urgent scientific problems limiting sustainable fisheries. SCEMFIS develops methods, analytical and survey tools, datasets, and analytical approaches to improve sustainability of fisheries and reduce uncertainty in biomass estimates. SCEMFIS university partners, University of Southern Mississippi (lead institution), and Virginia Institute of Marine Science, College of William and Mary, are the academic sites. Collaborating scientists who provide specific expertise in finfish, shellfish, and marine mammal research, come from a wide range of academic institutions including Old Dominion University, Rutgers University, University of Massachusetts-Dartmouth, University of Maryland, and University of Rhode Island.
The need for the diverse services that SCEMFIS can provide to industry continues to grow, which has prompted a steady increase in the number of fishing industry partners. These services include immediate access to science expertise for stock assessment issues, rapid response to research priorities, and representation on stock assessment working groups. Targeted research leads to improvements in data collection, survey design, analytical tools, assessment models, and other needs to reduce uncertainty in stock status and improve reference point goals.
Stove Boat Communications
SOURCE: Science Center for Marine Fisheries