The start of another fishing year brings new challenges and more questions for New England’s groundfish fleet. As the effects of dwindling cod stocks continue to ripple through the industry, fishermen and scientists are working together to gain a better understanding of the state of the resource. Various collaborative research projects focused on cod are currently underway throughout the region. Together these efforts aim to shed new light on the future of cod and contribute to more accurate stock assessments.
The spatial distribution of Atlantic cod, as well as the commercial cod catch in the Gulf of Maine, has changed over time. As a result, scientists wonder if the mix of spawning populations that are contributing to the biomass and catch has also changed. To gain a better understanding of the current state of cod in the Gulf of Maine and its potential for recovery, a team of scientists is working to understand the two main spawning groups that remain within the gulf.
Diversity in key characteristics, such as the genetic make-up, spatial behavior, and life history can confer resiliency to fishery resources in the face of changing environmental conditions and commercial fishing patterns. Understanding the remaining ecological diversity within the Gulf of Maine cod stock can provide insights relevant to promoting the recovery of depleted populations of cod.
Through a collaborative effort, researchers from GMRI, UMass Dartmouth’s School for Marine Science and Technology (SMAST), and the University of New Hampshire (UNH) are studying the spring and winter spawning complexes of cod in the Gulf of Maine. Aboard fisherman David Goethel’s F/V Ellen Diane, the team, led by Lisa Kerr of GMRI, has collected cod over the past year, gathering basic demographic information, fin clips for genetic analysis, otoliths for chemical analysis, and photos for body shape analysis. Together, this suite of information will provide insights on how winter and spring spawning cod differ from each other in their genetics, life history, and habitat use. This information is critical for better management and protection of the remaining spawning populations of cod.
Industry-based surveys are another approach that fishermen and scientists have used in New England and other parts of the country to improve the accuracy of stock assessments. These surveys are designed to complement the federal trawl surveys by expanding their spatial and temporal reach and providing finer resolution data using commercial fishing vessels as research platforms. New England fishermen are hopeful that this approach might start to fill data gaps in the current stock assessment and address the industry’s concerns around the federal trawl survey.
From 2002 to 2007, the Massachusetts Division of Marine Fisheries (MADMF) ran an industry-based trawl survey (IBS) for cod to investigate the spatial temporal distribution of Gulf of Maine cod. The program used four commercial trawlers to conduct surveys from the Canadian border south to Chatham, MA. Nearly ten years later, the project team is planning to revive the program, taking the lessons learned from the first cod IBS to develop a new survey design with industry participants. The team, led by Bill Hoffman of MADMF, hopes that in this next iteration, the new program can enhance the stock assessment by collecting samples outside of federal survey times and areas. They also hope to help improve management by assessing area closures, identifying the distribution of spawning cod and the co-occurrence of cod with other groundfish species.
Cod on Camera
Adding a new spin to the trawl survey, a team of researchers, led by Dr. Kevin Stokesbury of SMAST, is using cameras to gain a better understanding of cod abundance and spatial distribution in the Gulf of Maine. The team is testing a new underwater video sampling system that can count and measure fish as they pass through an open codend. This innovative approach builds off of Dr. Stokesbury’s work in the Georges Bank yellowtail flounder fishery and in the scallop fishery, where it has been successfully used to estimate scallop abundance for over a decade.
Unlike traditional trawl surveys that are limited by the length of tows and geographic extent, this video sampling system can capture hours of footage across a wider swath of area. This winter, the team tested the system aboard New Bedford fisherman Ron Borjeson’s F/V Justice on Stellwagen Bank.
When stock assessments first reported dramatic declines in Gulf of Maine cod, scientists and fishermen alike began asking questions. Together these various innovative collaborations are contributing to a better understanding of the state of the cod resource and strengthening relationships between fishermen, scientists, and regulators.
To learn more about these and other current collaborative projects occurring through the region visit www.gmri.org/fishtank