New Scallop Dredge Greatly Reduces Risks to Threatened Sea Turtles
The following was released by the Coonamesset Farm Foundation:
The New England Fishery Management Council (NEFMC) recently took action to reduce injury to sea turtles. The action requires the use of a new scallop dredge design that greatly reduces the risk of injury to sea turtles encountered during fishing operations. The dredge design, known as the Cfarm Turtle Deflector Dredge (TDD), evolved over several years’ research led by the Coonamessett Farm Foundation (CFF).
CFF, a non-profit research and education foundation, is funded by grants from the sea scallop industry’s research set aside (scallop RSA) program and the National Marine Fisheries Service Northeast Fisheries Science Center (NEFSC). The CFF is working with a diverse team of scientists and fishermen in a major effort to understand how the fishery is affecting the loggerhead sea turtle. Edward Welch, a New Bedford scallop captain for over 40 years said that “the first turtle I caught was in 2001 and I knew then we had to do something.”
The scallop fishery interacts with predominantly loggerhead sea turtles during the summer and fall in the Mid-Atlantic. Interactions between sea turtles and dredges are thought to occur in the water column during haul back as well as on the sea floor during active fishing. In 2003, over 750 loggerheads were estimated caught and with an injury rate estimated at 64%.
An initial CFF and Virginia Institute of Marine Science (VIMS) research effort led to the development of turtle chain mats to prevent turtles from entering the dredge when the gear is being hauled back through the water. The highly successful chain mats all but eliminated turtles from being captured by scallop dredges. Ronald Smolowitz, the designer of the chain mat, points out that “Although the chain mats greatly reduced sea turtle capture in scallop dredges, they did not eliminate the potential risk of a turtle being run over and injured by a dredge on the seafloor.” For several years, Smolowitz’s team of CFF researchers worked with the scallop industry and NEFSC to develop a turtle deflector dredge to further reduce the severity of impact and mortality of sea turtles from potential interactions on the sea floor.
In 2005, CFF, NEFSC and Southeast Fisheries Science Center conducted a study using sea turtles that died as a result of strandings. The carcasses were placed in the path of a standard New Bedford dredge to evaluate interactions and injuries. Prototypes of a modified dredge were also developed and tested. In 2008, again working with the NEFSC, the turtle deflector dredge was evaluated in Cape Cod Bay, Massachusetts. Nine sea turtle carcasses were used in the tests and five recovered carcasses were evaluated for injuries. The only observed carcass damage was superficial scratches and chips. The tests were also captured on video that showed all carcasses hit the dredge at some point and passed over the dredge frame.
The new TDD design makes it highly likely that a turtle will not be run over by the dredge, and the TDD is expected to decrease injuries to turtles by 56% and possibly eliminate serious injuries altogether.
Deirdre Boelke, the Scallop Plan Coordinator for the NEFMC believes the Council’s recent decision to recommend implementation of the TDD in the scallop fishery was a very positive action that will have real and measurable benefits for sea turtles. “From start to finish, this gear modification is an ideal example of how the Council process can and should work. A problem was identified, a solution was devised, industry partnered with appropriate researchers to test it, and finally the management process developed and analyzed a range of alternatives with input from the public and NMFS. CFF took the lead in developing this solution. Implementation of the TDD will serve as a great acknowledgement of their dedication and hard work.”
To further understand the behavior of the turtles and their population status, the Coonamessett Farm Foundation (CFF) is collaborating with the NEFSC and others. The research involves the use of dredge mounted video cameras, a remotely operated vehicle (ROV), and satellite tags placed on captured turtles. Recent work supported by the satellite tracking studies, indicates that more than 800,000 loggerheads live in the northwest Atlantic Ocean.
Note: Pictures are available at http://www.coonamessettfarmfoundation.org in the photo gallery