Science Center for Marine Fisheries Archives - Page 3 of 6

Study finds existing forage fish management is working

July 9, 2021 — Efforts to ratchet down fishing effort on species like herring and menhaden in the name of “extra precautionary management” in most cases are unlikely to bring additional benefits for stocks of predator species that eat them, according to a new study.

“Our results indicate that predator productivity was rarely influenced by the abundance of their forage fish prey,” wrote authors Christopher Free of the University of California-Santa Barbara, Olaf Jensen of the University of Wisconsin-Madison, Ray Hilborn of the University of Washington. “Only 6 predator populations (13 percent of the total) were positively influenced by increasing prey abundance and the model exhibited high power to detect prey influences when they existed,” according to their paper titled “Evaluating impacts of forage fish abundance on marine predators,” originally published in the journal Conservation Biology.

“These results suggest that additional limitation of forage fish harvest to levels well below sustainable yields would rarely result in detectable increases in marine predator populations.”

The findings were released July 6 through the Science Center for Marine Fisheries, a cooperative effort to improve sustainability of fisheries and reduce uncertainty in biomass estimates with work by university partners led with the University of Southern Mississippi Virginia Institute of Marine Science, College of William and Mary, as academic sites.

“Our work suggests that the sustainable limits that we already employ are sufficient for maintaining forage fish abundance above the thresholds that are necessary for their predators,” Free of UC Santa Barbara in a statement describing the findings. “Predators are highly mobile, they have high diet flexibility, and they can go and look for forage fish in places where they’re doing well, switch species for species that are doing well, and have often evolved to breed in places where there’s high and stable forage fish abundance.”

Read the full story at National Fisherman

New Study: Precautionary Catch Limits on Forage Fish Unlikely to Benefit Predators

July 6, 2021 — The following was released by the Science Center for Marine Fisheries:

A newly released study finds that, for many predator species, extra-precautionary management of forage fish is unlikely to bring additional benefits. How to manage forage fish sustainably, both by themselves and for the rest of the ecosystem, has become a much-discussed topic in fisheries management, with regulators of several forage fisheries beginning to adopt precautionary strategies on the premise that they will better provide for the needs of predator species including seabirds, marine mammals, and fish.

The study, from Drs. Chris Free of the University of California-Santa Barbara, Olaf Jensen of the University of Wisconsin-Madison, and Ray Hilborn of the University of Washington, examines decades of historical abundance data of both forage species and their predators, and uses mathematical models to determine to what extent predator populations benefited from increasing abundance of their forage fish prey. Of the 45 predator populations examined, only 6, or 13 percent, were positively influenced by extra forage.

“Our work suggests that the sustainable limits that we already employ are sufficient for maintaining forage fish abundance above the thresholds that are necessary for their predators,” said Dr. Free. “Predators are highly mobile, they have high diet flexibility, and they can go and look for forage fish in places where they’re doing well, switch species for species that are doing well, and have often evolved to breed in places where there’s high and stable forage fish abundance.”

The results have important implications for how strictly to manage forage fisheries. The study finds that, at least in forage fisheries that are already being well managed and are closely monitored, adopting additional precautionary measures will “rarely” provide any additional benefits to predator population growth. However, fishery managers who deal with less well-monitored fisheries may consider more precautionary strategies.

“In places of the world where we already have really strong, very effective fisheries management, additional limitations on forage fish catch are not likely to benefit their predators,” said Dr. Free.

“Management of forage fish populations should be based on data that are specific to that forage fish, and to their predators,” said Dr. Jensen. “When there aren’t sufficient data to conduct a population-specific analysis, it’s reasonable to manage forage fish populations for maximum sustainable yield, as we would other fish populations under the Magnuson-Stevens Act.”

According to the models used in the study, other environmental factors, such as water temperature, are more likely to influence predator populations. These results are consistent with previous efforts to examine the relationship between predator and prey populations.

“What we’ve done here that’s different from previous analyses is try to control for some of the other factors that influence predator population dynamics,” said Dr. Jensen. “In this case, we included in the models a covariate representing ocean temperature.”

SCEMFIS produced a video of the authors and independent experts discussing the results of the paper. Watch it here.

Read the full release here

Science Center for Marine Fisheries Recognizes Its Women Scientists in Celebration of Women’s History Month

March 31, 2021 — The following was released by the Science Center for Marine Fisheries:

As Women’s History Month comes to a close, the Science Center for Marine Fisheries (SCEMFIS) is celebrating the contributions of the women students and staffers who are a driving force behind the Center’s current success, and who are essential to our important fisheries science research.

SCEMFIS operates two main research centers, the Gulf Coast Research Lab at the University of Southern Mississippi and the Virginia Institute of Marine Science at the College of William and Mary. This year, we have an amazing team of PhD and Master’s degree students working at both sites, contributing to our work on finish and shellfish.

Here are the stories of the students and scientists that are part of the SCEMFIS team, who will make up the next generation of leaders in marine science.

Kathleen Hemeon is a 3rd year PhD candidate at the Gulf Coast Research Lab at the University of Southern Mississippi. In her second year as a PhD student, she participated in a National Science Foundation non-academic internship, which funded a six-month collaborative research study at the Population Biology Branch of the NMFS Northeast Fisheries Science Center in Woods Hole, MA. As an intern, she worked to develop age-error estimations and protocols that arise when aging the commercially harvested ocean quahog (Arctica islandica), the longest-lived bivalve on Earth. These data will help researchers identify age-reader bias and precision to report with age estimations, in addition to standardizing aging procedures for an animal that is notoriously difficult to age.

Kathleen will continue her work on ocean quahog with her dissertation, which will better explain the population dynamics of two, Mid-Atlantic quahog populations. This dissertation follows Kathleen’s previous work with green sturgeon, inland fisheries, and natural resource management, in addition to an earned B.S. from Western Washington University and M.S. from James Madison University.

Jill Sower is a second year Master’s student at the Gulf Coast Research Lab. Her work at GCRL focuses on examining population dynamics for ocean quahogs off the coast of New Jersey in comparison to different quahog populations from along the coast of New England.

Jill received a B.S. in Wildlife Conservation and a B.A. in Spanish from Virginia Tech in Blacksburg, VA. She hopes to graduate in Spring 2022, and after finishing her degree, she would like to continue working in a research position at a coastal university along the East Coast.

Alyssa LeClaire is a Master’s student at the Gulf Coast Research Laboratory. Working in collaboration with Virginia Institute of Marine Science, her work includes collecting samples from archived ocean quahog shells found offshore of the Delmarva Peninsula. Carbon dates will be used to determine the time scale of the ocean quahog’s range shift across the continental shelf in Mid-Atlantic Bight, coinciding with fluctuation of the Cold Pool and historical climate events. She has sampled shells that are over 4000 years old.

She is applying for an NSF nonacademic internship to work with NOAA’s Northeast Fisheries Science Center (NEFSC) and Geophysical Fluid Dynamics Laboratory (GFDL). This five-month internship would be to determine if the Cold Pool has significantly changed, in terms of size and location, and if this change is impacting the available habitat of ocean quahog. Alyssa received her BS in Marine Science at Coastal Carolina University in South Carolina.

Laura Solinger is a PhD student in the Gulf Coast Research Lab. Her work focuses on developing a risk-based approach to assess the effectiveness of different management strategies on fisheries resources, including summer flounder and Atlantic surfclam. Laura was awarded an NSF non-academic internship to collaborate with the stock assessment lead for Atlantic surfclam, Dr. Daniel Hennen, at the Northeast Fisheries Science Center, and she has also collaborated on projects for management of gulf oysters, abalone disease transmission, and forecasts of clam fisheries given projected offshore windmill construction.

Laura received her BS in Biology with a focus on Marine Science from the University of South Florida, and is currently finishing her MS in Fisheries Biology with Humboldt State University. After her PhD, Laura hopes to work with private and public fisheries organizations to develop stock assessment models, assess their effectiveness and continue advancements to incorporate new data sources and environmental variables into models.

Alexis Hollander is a Master’s Student at the Virginia Institute of Marine Science in Dr. Roger Mann’s Molluscan Ecology Lab. For her Master’s research, Alexis is investigating the impacts of climate change on the growth and distribution of Atlantic surfclams (Spisula solidissima). The moving footprint of the range of exploited surfclams in these regions over the past four decades is now well documented in both Northeast Fisheries Science Center (NEFSC) stock assessment surveys and the gradual northeasterly movement of harvest activity. This project is developing a 33-year retrospective, spatially explicit time series of growth rates in surfclams collected over the surveyed range to both document the moving footprint in terms of population productivity and provide an explicit forward projection of future productivity.

Alexis has a career goal of serving as an educator and mentor to college students.

Alexandria Marquardt is an ecologist and PhD student in the Department of Fisheries Science at Virginia Institute of Marine Science studying Eastern oyster (Crassostrea virginica) biology and population dynamics in the Chesapeake Bay. Her work focuses primarily on marine invertebrates and addresses applied questions that directly inform management and restoration of harvested species. Alex’s PhD research investigates post-settlement growth and mortality in oysters in the Chesapeake Bay and compares existing and fossil oyster reefs. Alex is collaborating with SCEMFIS this spring, assisting with ocean quahog and surf clam research, while searching for fossilized oysters.

Her career goals are to work on research and monitoring programs that engage local communities and stakeholders to share knowledge, build relationships, and facilitate participation in scientific research. Alex completed her BS in Fisheries and Wildlife Science at Oregon State University and MS in Biological Sciences working with Dr. Ben Ruttenberg at California Polytechnic State University, San Luis Obispo.

About SCEMFIS

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.

Science Center for Marine Fisheries Approves $100,000 in Research Grants for 2021

March 3, 2021 — The following was released by the Science Center for Marine Fisheries (SCEMFIS):

The Science Center for Marine Fisheries (SCEMFIS) has approved 4 new research projects, with $100,000 in funding, to start 2021. Approved at the Center’s annual winter meeting, the new projects will focus on improving data collection and scientific surveys in important finfish and shellfish fisheries.

These projects include efforts to improve how menhaden are tagged and tracked; analyzing the age and length composition of the chub mackerel population; improving clam dredge performance; and improving collection methods for surfclams and quahogs. All projects were approved by the SCEMFIS Industry Advisory Board (IAB), which is comprised of the Center’s industry partners in the finfish and shellfish fisheries.

SCEMFIS is a member of the National Science Foundation’s Industry-University Cooperative Research Centers (IUCRC) program, a federal initiative to bring together academic researchers and industry members to fund projects improving our understanding of economically important issues.

The following projects were approved at the winter meeting:

Understanding the utility of archived tag-recapture data for evaluation of movement and mortality estimation – As a changing climate forces species to shift geographical ranges, tracking population data and location has become increasingly important. The project, by Dr. Robert Leaf (University of Southern Mississippi), will directly address “high” priority needs listed in the menhaden stock assessment. ($19,874 in funding)
Characterization of the length and age composition of the Atlantic Chub Mackerel fishery in the mid-Atlantic for 2021 – In a collaboration with SeaFreeze Ltd. and Lund’s Fisheries Inc., this study, lead by Dr. Robert Leaf, will characterize the age and length composition of Atlantic chub mackerel in the commercial fishery for the 2021 season. The project addresses the assessment’s needs to provide “adequate scientific information” for the Atlantic chub mackerel stock. ($14,035 in funding)
Development of Improved Clam Dredge System using Theory, CFD, and Experiment – This study, by Dr. Eric Powell (University of Southern Mississippi), will research potential improvements to the current clam dredge system, a system which has not been updated in decades. Dr. Powell plans to work with the Center for Water and the Environment at the University of Texas, Austin in order to improve the efficiency of dredge systems, increasing catch rates, reducing fuel consumption, and reducing engine emissions. ($65,634 in funding)
Design of a dredge for collection of juvenile Surfclams and Ocean quahogs – This study, lead by Dr. Eric Powell, will support shellfish research by improving collection methods for surfclams and ocean quahogs. The project will design a cost-effective dredge to sample juvenile ocean quahogs and surfclams for research and data collection. Improving juvenile clam sampling will provide a more accurate estimate of population size, frequency and recruitment for surfclams and quahogs. ($7,590 in funding)

Read the full release here

New Study Finds Strong Currents Off Nantucket Prevent Development of Stable, Biologically Diverse Benthic Communities

February 22, 2021 — The following was released by the Science Center for Marine Fisheries (SCEMFIS):

Complex ocean environments, full of features such as cobble, rocks, and boulders, are usually home to a diversity of marine life; as a result, fisheries managers have often sought to preserve these areas from outside interference. But one such area off the coast of Nantucket may be a significant exception to this rule, according to a new study from the Science Center for Marine Fisheries (SCEMFIS).

The study, from Eric Powell, Jeremy Timbs, and Kelsey Kuykendall of the University of Southern Mississippi and Roger Mann and M. Chase Long of the Virginia Institute of Marine Science, analyzes survey data from the Nantucket Shoals area of the Great South Channel in the Atlantic, an area of considerable substrate complexity and home to the Great South Channel Habitat Management Area (HMA). But the study found that, due to the area’s strong currents and seafloor activity, much of the faunal diversity expected from substate complexity has failed to develop.

Specifically, the study found few examples of the kind of charismatic marine life—such as tunicates, sponges and anemones—that usually attach themselves to prominent features like boulders and rocks in habitats where they occur. The study attributes this to the high-energy currents that frequently run through the area, as well as the sand on the seafloor regularly scouring the rocks as a result of the currents. The absence of mussels attached to hard bottom features, and the presence of barnacle scars where barnacles have been eroded off the rocks, show clear evidence of the rigor of the benthic environment that minimizes the use of these substrates by attached bottom creatures.

According to the study, the tidal activity and strong currents “minimize the importance of cobbles, rocks, boulders, and shells in community structure in some subtidal high-energy regimes, defying expectations from their contribution to substrate complexity.”

“You’d expect the type of environment you see in Nantucket Shoals to support a significant amount of life on its rocks and bottom features, but that’s just not the case here,” said Dr. Eric Powell, one of the authors of the study. “These findings show that we need to consider the whole range of factors when determining which habitats are most likely to support biodiversity.

”The findings are significant for future management of the Great SouthChannel area. Much of the region has been part of a HMA since 2018, which prohibits bottom-tending fishing gear. It is also home to important fishing grounds for surfclams, and is one of the most resilient areas for surfclam habitat. Surfclam fishermen have lost access to these grounds since the HMA went into full effect.

Most notably, the Nantucket Shoals area within the HMA was critical for smaller clam vessels fishing out of Massachusetts; several surfclam companies caught up to 90 percent of their harvest from the area. Since it was first established, members of the surfclam industry have argued that this habitat area does not contain enough complex habitat to justify the number of restrictions in place, especially considering the cost to the industry. The study indicates that the area may not be a good candidate for habitat protection.

“It’s important that conservation efforts target areas that are most likely to benefit them, especially if these efforts would interfere with important fishing grounds,” said Monte Rome a member of the SCEMFIS IAB. “This study helps us better identify areas that do not particularly benefit conservation efforts.”

Read the full release here

Offshore wind turbines could affect Mid-Atlantic ‘cold pool,’ study shows

February 2, 2021 — Building arrays of offshore wind turbines off the Mid-Atlantic states could have effects on the annual cycle of ocean water temperatures that are critical to the region’s fish and shellfish habitat, a new study suggests.

The paper from the Science Center for Marine Fisheries surveys years of research around northern European offshore wind installations, particularly in the North Sea. Travis Miles, Sarah Murphy, Josh Kohut, Sarah Bosetti, and Daphne Munroe, all of Rutgers University, reviewed existing literature on how three decades of wind farm construction has affected ocean environments in Europe.

The group looked at earlier findings about how the turbine structures may affect the local environment, including questions about how turbine foundations may interact with tidal currents, temperatures and sediments in the water column, and how the turbines’ extraction of energy from wind may affect the surface of the ocean around them.

Of particular interest is the so-called “cold pool,” the seasonal stratification of cooler water close to the bottom, peaking in summer and turning over in fall and spring. It’s important to the survival of key, commercially important species including scallops and surf clams, and is a driver of primary production and nutrients for the ocean food web.

Read the full story at National Fisherman

New Study: Little Known About How Wind Farms Affect Critical Mid-Atlantic Ocean Feature

February 1, 2021 — The following was released by the Science Center for Marine Fisheries:

While not often in the spotlight, an oceanographic feature known as the “cold pool,” which stretches from Massachusetts to North Carolina, is critical for the health of many marine species. However, a new study from the Science Center for Marine Fisheries finds that, despite its importance, not much is known about how the growing offshore wind industry could affect the cold pool, and the marine life that depends on it.

The study, from Dr. Travis Miles, Sarah Murphy, Dr. Josh Kohut, Sarah Bosetti, and Dr. Daphne Munroe, all of Rutgers University, reviewed existing literature on how wind farm construction affects ocean environments in Europe, where most offshore wind farm construction has so far taken place, and lays out what can be learned from the European experience, and what aspects about potential interactions remain unknown.

Spanning much of the Mid-Atlantic Bight, the cold pool is a layer of cold water, just beneath warm surface water, extending to the ocean bottom that forms every spring and lasts until the fall. Its annual appearance is a vital part of the life cycle of many marine species.

“It supports some of the most lucrative fisheries in the world, some of the most sustainably managed fisheries in the world,” said Dr. Munroe. “We’ve got species that live off the coast of New Jersey that you wouldn’t expect to live here because they need cold water. And it’s that cold pool that provides that habitat that allows them to live here.”

According to the study, Europe’s experience with wind farms has shown that there is some impact from the placement of wind turbines. Specifically, the study states, “turbines induce downstream impacts on ocean velocities, turbulence, and stratification.” However, the extent of this interference is highly dependent on the site, the size of the wind farm and turbines, and underlying ocean conditions and wind speed.

It is not clear how much the European experience will translate to the Mid-Atlantic. With the cold pool, the waters of the Mid-Atlantic are much more clearly stratified between layers of warm and cold water, and tidal currents are generally weaker than those in Northern Europe. Those two factors may affect whether or not wind turbines disrupt the cold pool and the ocean stratification that is an essential feature for the region’s marine life.

“Understanding how fast the ocean moves in our region relative to how fast the ocean moves in other regions where some of this research is done is super critical,” said Dr. Miles. “Tides in Europe move very fast. In the Mid-Atlantic region we have relatively slow currents unless we have storms come through.”

The study’s authors specifically identify three areas that will require future study: the level of overlap between the cold pool and the areas currently being considered for offshore wind development; the threshold of stratification that will be affected by offshore wind turbines; and how development will impact the seasonal development of the cold pool.

“We understand a bit about the cold pool, we understand a little bit about how offshore wind has impacted seasonal stratification off the European coast, but we don’t know what will happen when wind farms are deployed off the Mid-Atlantic coast in the specific conditions of the cold pool,” said Dr. Kohut.

Watch the researchers discuss their findings here

New Study Finds Ways to Potentially Reduce Uncertainty in Shellfish Assessments

December 4, 2020 — The following was released by the Science Center for Marine Fisheries:

Researchers working to determine the abundance of shellfish, including surfclams and ocean quahogs, have faced limits in getting a precise count due to the uncertainty inherent in stock assessment surveys. A new study, by Leanne Poussard, Dr. Eric Powell, and Dr. Daniel Hennen and published this month in Fisheries Research, examines one of these sources of uncertainty.

Uncertainty is a major factor affecting all stock assessments, which rely on estimating the size of an entire population based on the data provided by a small sample. Identifying these sources of uncertainty is key to producing precise estimates. In the case of surfclams and other shellfish species, a main driver of uncertainty is how efficient the dredges used during the stock surveys are in catching shellfish.

The National Marine Fisheries Service (NMFS) conducts what are known as depletion experiments to measure how efficiently a dredge harvests clams; a dredge will be run multiple times in a single area, and how quickly the catch declines with each subsequent tow will be used to estimate its efficiency. NMFS has also developed a statistical model to estimate the level of uncertainty present in these experiments.

Using this model, as well as running simulations of dredge tows, the new study finds that uncertainty in depletion experiments can be significantly reduced by taking measures such as running additional tows, and having more overlapping tows during the course of an experiment to measure gear efficiency. Having these measures in place could significantly reduce the role of survey gear as a source of uncertainty.

“By making modest changes to the way we conduct surfclam depletion experiments, we can potentially reduce uncertainty and be more confident in the ultimate results of clam stock assessments,” said Leanne Poussard, the lead author of the study. “This study provides clear guidance on the best ways to conduct future shellfish depletion experiments.”

“As a participant in NMFS surfclam and ocean quahog stock assessments over the past 30 years, I can attest that uncertainty regarding dredge efficiency has been a continuing source of scientific caution in projecting stock biomass, and appropriate levels of commercial harvest,” said Tom Alspach, of Sea Watch International. “This new work should significantly ameliorate that uncertainty, allowing fishery managers to appraise stock sustainability with more confidence, leading in turn to stability in annual quotas for the direct benefit of the harvesting sector. This is why the surfclam/ocean quahog industry has enthusiastically provided financial support for the research initiatives of SCEMFIS.”

The study is the latest to be funded by the Science Center for Marine Fisheries (SCEMFIS), and is part of the Center’s work of improving shellfish science and management. SCEMFIS is part of the National Science Foundation’s Industry-University Cooperative Research Center program. Working together with its partners in the fishing industry, SCEMFIS identifies the most pressing needs in finfish and shellfish science. In the last year, SCEMFIS funded over $191,000 in scientific research.

Science Center for Marine Fisheries Welcomes Atlantic Red Crab Company as Newest Member

November 5, 2020 — The following was released by the Science Center for Marine Fisheries:

The Science Center for Marine Fisheries (SCEMFIS) is pleased to announce that the Atlantic Red Crab Company has become the latest company to join the Center’s Industry Advisory Board. With this new addition to our growing list of industry partners, the Center is ready to continue its record of collaborative fisheries research.

For the past 7 years, SCEMFIS has brought together leading academic researchers and members of the fishing industry to identify the most pressing needs in marine science research. With the support of its industry partners, SCEMFIS scientists have published innovate studies providing new understanding of finfsh and shellfish. In 2020 alone, the Center funded $191,000 in new research projects addressing these priorities.

“The Atlantic Red Crab Company has been involved in cooperative science for years, and sees this opportunity to join SCEMFIS as a way to leverage resources and gain a broader scientific perspective,” says Jon Williams, owner of the Atlantic Red Crab Company.

Based in New Bedford, Massachusetts, the Atlantic Red Crab Company harvests red crab in the waters of the Northeast U.S. The red crab fishery is sustainably managed, and red crab is listed as a “good alternative” by the Monterey Bay Aquarium’s Seafood Watch program.

“The Atlantic Red Crab Company is a great new addition to SCEMFIS,” said Greg DiDomenico, the Chair of SCEMFIS. “Their commitment to sustainability and collaborative research closely aligns with the Center’s mission.”

SCEMFIS, established in 2013, is one of the centers in the National Science Foundation’s Industry-University Cooperative Research Centers program, which facilitates collaborative research between academia and industry. This year, SCEMFIS researchers have published studies on the economic impact of the squid and summer flounder fisheries; how the federal government did not properly consider the impact offshore wind development has on fisheries; the current state of the Atlantic menhaden stock; and ways to improve the management of gray seals and the fisheries that interact with them.

About SCEMFIS

SCEMFIS Research Provides New Insights on Gray Seals; Suggests Alternatives to Current Management

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.”

Read the full release here