Field Trials of 4″ Rings in the Inshore Scallop Fishery in the Gulf of Maine
Scallop drag selectivity has been of interest to fishermen and scientists working in Maine’s sea scallop fishery, and in late 2003, a collaborative project was undertaken to look at the effects of ring size on selectivity. Capt. Steven Patryn, owner of the Jonesboro-based F/V Northern Eagle, teamed up with Extension Associate Dana Morse, to evaluate the effects of rigging a drag with 4″ rings, compared to the regulated size of 3.5″. Robert Holland, also of Jonesboro, participated with his boat, the F/V Double J, captained by Larry White. The Northeast Consortium funded the study. An important aspect of the project was to see if undersized scallops were allowed to escape more effectively through the bigger rings, without impacting the catch of legal size scallops. In the 2003/2004 fishing season, the legal shell size for a scallop was 3.75″, though the legal size is scheduled to jump to 4″ for the 2004/2005 fishing season. Reducing the number of sub-legal scallops that make it to the deck of a boat is important, both to minimize the stress on the scallops, and to reduce the possibility of harvesting ‘shorts.’
Two identical drags were built by Blue Fleet, Inc., of New Bedford, MA. Two inch head bails, five and one-half feet in width, were fitted either with the control rings (3.5″) or the experimental rings (4″), and rigged to a pocketbook-style dump. The boats fished side by side, with observers quantifying the catch. Five days were spent fishing in Cobscook Bay, and five days were spent fishing the area from Buck’s Harbor to Cutler. All fishing was done during November of 2003, courtesy of a Special License issued by the Maine Dept. of Marine Resources; good communications continued between the project personnel and Marine Patrol throughout the fieldwork.
Results to date indicate that by volume, catch of urchins was affected by the larger rings, but that catch volumes of starfish, sea cucumbers and ‘trash’ was not affected. Catch volumes of scallops seem to be reduced overall by about 20%. Estimations were made, based on the sampling data, of the numbers of sub-legal and legal scallops retained by the two drags. At the 3.75″ shell height, the larger rings lost about 10% of the legal catch by number. At the 4.0″ shell height, the larger rings lost about 3% of the legal catch, by number. Length frequency analysis is ongoing. Preliminary results were presented at the 2004 Maine Fishermen’s Forum, with Steven and Dana presenting.
More data is needed to better understand the selectivity of scallop drags inshore, especially in deeper waters: the present study towed only down to a depth of 20 fathoms (120 feet) or so. Scallop catch data is also highly variable, so more tow data would help to clarify drag selectivity. Future work should also encourage the crew to separate all scallops into legal size or sub-legal size, prior to observer workup; this would allow better estimation of the change to the legal catch.
For more information, contact Dana Morse.