In May, the Department of Marine Resources (DMR) was awarded a three-year, $714,000 grant by the National Marine Fisheries Service Section 6 Species Recovery Grant program to assess the use of vertical lines in fixed gear fisheries in the Gulf of Maine. The objective is to analyze existing vertical lines in different parts of the Gulf of Maine to inform management decisions to strengthen protections for right whales in the region. The project will document the types and rigging of vertical lines currently in use in various regions of the Gulf as well as the functional breaking strength of actively fished vertical lines. The study includes lobstermen in Maine, New Hampshire, Massachusetts, Rhode Island, and Connecticut.
Erin Summers, a marine resource specialist at DMR, is project manager. Patrice McCarron, executive director of the Maine Lobstermen’s Association, Forrest Bell, principal scientist at FB Environmental Associate in Portland, and Yong Chen, fisheries scientist at the University of Maine, are co-partners in the project.
“The project’s primary goals are to document what types of rope fishermen use in their vertical lines and how those lines are rigged, determine the functional breaking strength of existing vertical lines, and document the hauling loads fishermen experience by installing load cells aboard fishing vessels,” Summers said.
The first step is to ask lobstermen about their vertical lines. If managers propose changes in how lobstermen fish vertical lines, it is important to understand what is currently in use by the industry and why. To do this, an online survey tool is being developed to make it easy for lobstermen to provide information on the surface systems and the type of rope and rigging used in their vertical lines. The survey will include questions about the type and diameter of ropes used, use of knots and splices, percent of sink to float rope, surface system configuration, anchors used and weight of traps, and general area and depth fished. The National Oceanic and Atmospheric Administration (NOAA) will be conducting a similar, paper survey in the fall. However, the purpose of DMR’s survey is to gather needed data before the Atlantic Large Whale Take Reduction Team (TRT) meets in October to discuss potential additional regulations to protect the endangered right whale.
Researchers have proposed that lobstermen be required to fish endlines comprised of rope that breaks at 1700 pounds when new. However, lobstermen do not fish a single piece of new rope, rather they join multiple pieces of rope together, using splices, knots and other methods, and fish that rope for five or more years. Splices are known to decrease the strength of rope by 25% and knots reduce the strength of the rope even more. Understanding the functional breaking strength of existing rope will provide an important baseline understanding of currently fished rope and where weak points are located. “We want to know the real breaking strength of used rope, not just the breaking strength when it is new,” explained Summers. The project will collect the full length of vertical line from trap to buoy.
Beginning in July, lobstermen will have the opportunity to have a load cell device installed on their boat. The load cell will measure the pounds of pressure or the hauling load experienced by the endline as it is pulled from the bottom by the hauler. “This will allow us to get data on the pounds of pressure applied to the vertical line in varying conditions and different gear characteristics,” Summers explained. A South Thomaston lobsterman has piloted the use of a load cell on his vessel in this spring. The machine recorded the loads experienced on his endlines over the course of a week during the hauling of 140 16-trap trawls. The preliminary data suggest that his vertical line experienced more than 2,000 pounds of pressure when his traps were overset by other trawls.
“It is important that we understand the range of loads experienced by endlines throughout the Gulf of Maine. There are many variables that will impact the results such as weather, tides, set-overs, hang downs and the size of the vessel. Smaller vessels are generally able to absorb some of the shock load while larger vessels absorb less causing the vertical lines to experience more strain,” Summers explained. “Documenting these factors will determine how strong vertical lines need to be to conduct the fishery safely under a variety of conditions.”
Finally, Yong Chen at the University of Maine will create a computer model that describes the relationship between the breaking strength of vertical lines, strain experienced by the vertical lines under a variety of conditions and environmental factors such as location and time of year. “The aim of the model is to determine the need, impact, and conservation benefits of management actions targeting vertical lines based on different variables,” Summers said. “It will yield vital information on the effectiveness of any proposed regulations.”
“DMR’s project will help ensure that we have a grasp on what our lobstermen are fishing and why, to allow managers to assess both the pro’s and con’s of any proposed changes. Fishing practices generally evolve out of necessity and this project will help managers understand why lobstermen require stronger ropes in certain segments of the fishery. We are not interested in implementing any measures that threaten fishermen’s safety, will lead to massive gear loss or do not provide adequate protection for whales,” said the MLA’s McCarron.Category: Management, Science