Local Fishermen Lead Cod Research
South Shore fishermen partner with scientists to protect spawning cod.
SCITUATE, MA | January 08, 2014
Local fishermen have always known that cod return to the waters off the South Shore to breed this time every year – clustering in large numbers, spawning and providing our best hope of a future for healthy cod populations.
Now, scientists and fishermen are working together to use an “E-Z Pass for fish” to gather data about fish behavior, to better protect this iconic species and the communities that depend upon it.
Concerned commercial fishermen from the South Shore sought out scientists from The Nature Conservancy, the Massachusetts Department of Fish and Game’s Division of Marine Fisheries (MADMF), the University of Massachusetts Dartmouth and the National Oceanic and Atmospheric Administration, to help them map out exactly when and where spawning occurs, with the goal of protecting local cod during their spawning season.
“South Shore fishermen approached us to help protect these spawning cod with the future of the fishery in mind, and the collaborating researchers jumped at the chance to work closely with them,” said Chris McGuire of The Nature Conservancy in Massachusetts.
Over the next few weeks, local fishermen, working with scientists from MADMF and UMass Dartmouth’s School for Marine Science and Technology (SMAST), will hook spawning cod, implant electronic tags and then release the fish back into the sea. The project’s goal is to protect these local fish during spawning, as they are particularly vulnerable during this period.
Local fishermen are now seeing cod only during their spawning season in the late fall and early winter, whereas they used to be abundant for much of the year, explained Frank Mirarchi, who has fished from Scituate Harbor since 1962 and has personally witnessed a decline in cod abundance. Because such factors as warmer seawater and increased predation have made the fishing business on the South Shore ever more uncertain, his son has recently made the difficult choice to leave the fishery, Mirarchi said.
“We hope to provide these fish with protection while they’re vulnerable,” Mirarchi said. “The expectation is that we can provide discrete, small protected areas which will not be disruptive to fishing, while helping the cod stock to recover.”
Each electronic tag, once deployed, emits a coded sound roughly once a minute for up to six years, a signal that’s recorded whenever the fish passes within range of a network of receivers deployed on the sea floor by MADMF. Each tag has a unique acoustic signature, allowing scientists to track individual fish using the more than 3 million pings each tag will emit over its lifetime.
“It is sort of like an E-ZPass for fish,” McGuire said.
This information allows researchers to visualize the behavior of each fish while on the spawning grounds, and exactly when they leave which is needed for defining a seasonal closure and also to better understand spawning behavior, he explained.
“The tagging technology has been an excellent tool for studying spawning cod in Massachusetts Bay and our improved understanding of their behavior will help to inform stock assessment and fishery management for rebuilding the resource and the fishery,” said Doug Zemeckis, SMAST collaborator and PhD student at UMass Dartmouth.
“Cooperative research like this effort involving fishermen, government agencies and environmental organizations is vital to improving fisheries management for species like Atlantic cod,” said Massachusetts Department of Fish and Game Commissioner Mary Griffin.
“Our work tagging and tracking Gulf of Maine cod in Massachusetts Bay over the past decade has greatly improved the understanding of cod behavior and movement patterns when spawning,” said Paul Diodati, Director of the Division of Marine Fisheries and Massachusetts Marine Fisheries Institute Co-Chair.
“The importance and biological significance of small discrete spawning groups to the overall health of the resource is much clearer today because of our past work and it has aided in refinement of fisheries management strategies. We look forward to making additional advances in research as result of this new collaborative effort in Massachusetts Bay,” Diodati said.
Researchers are also recording the grunting sounds that male cod make to defend their territories and to attract females. Underwater microphones, deployed by NOAA scientists from the Northeast Fisheries Science Center, will record fish vocalizations, which can be used to characterize the timing of the winter spawning period, as well as the relative abundance when compared to past data. Federal researchers from the Northeast Fisheries Science Center and the Stellwagen Bank National Marine Sanctuary use this same equipment to monitor whales.
“Passive acoustics – or listening for cod sounds ¬– is an ideal way to monitor the seasonal presence and persistence of cod spawning aggregations over long time periods,” explained Sophie Van Parjis, of the Passive Acoustic Research Group at NOAA’s Northeast Fisheries Science Center in Woods Hole, MA.
“Passive acoustic recorders can listen continuously for up to six months, regardless of weather conditions. We are currently looking at historical data for this area (2004-2014), to look at how the presence of cod has changed over time. In addition, our passive acoustic recordings will help define the start and end of the spawning season, so we can more accurately define the time period needed to protect these aggregations,” Van Parjis said.
Atlantic cod is central to Massachusetts history – fishing helped build the state’s economy and remains an important industry. However, the cod population has seen steep declines in the last 20 years and despite drastic measures to reduce fishing pressure, remains at historic lows. This year, local fishermen faced a devastating 78 percent cut in the Gulf of Maine cod annual catch limit, which has severely impacted fishermen across the Bay State.
Ultimately, the fishermen and scientists will bring the spawning data to the New England Fisheries Management Council to inform future management decisions designed to care for this valuable cod population.
“This groundbreaking, collaborative effort between commercial fishermen, Massachusetts’ scientists, and the environmental advocacy community is a perfect example of a forward-thinking partnership that is needed to bring critical answers to the groundfish industry,” said Congressman Bill Keating, who represents the South Shore, South Coast, and Cape and Islands.
“With this project, we will truly come to understand and better predict the natural habits of cod and advance our industry by better protecting spawning populations and further restoring this vital stock. I applaud The Nature Conservancy and its partners for this initiative.”
Video assets, including b-roll and brief field interviews are available at: https://vimeo.com/naturenewengland
High-resolution photos are available for download upon request, and a sampling of photos can be viewed at: http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/massachusetts/explore/ma-cod-tagging-slideshow.xml
The Nature Conservancy is a leading conservation organization working around the world to conserve the lands and waters on which all life depends. Visit The Nature Conservancy on the web at www.nature.org. To learn about the Conservancy’s global initiatives, visit www.nature.org/global. To keep up with current Conservancy news, follow @nature_press on Twitter.