Out with the old and in with the new: T90 codends improve size selectivity in the Canadian redfish ( Sebastes mentella) trawl fishery

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Cheng, Zhaohai, Winger, Paul D., Bayse, Shannon M., Kebede, Gebremeskel Eshetu, DeLouche, Harold, Einarsson, Haraldur Arnar, Pol, Michael V., Kelly, David, Walsh, Stephen J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2020
• Subjects: Sebastes mentella
• Online Access: http://dx.doi.org/10.1139/cjfas-2020-0063; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2020-0063; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2020-0063

The size selectivity of four codends were compared in the Gulf of St. Lawrence, Canada, redfish fishery (Sebastes mentella), including the regulated diamond mesh codend with a mesh opening of 90 mm (T0) and three experimental codends of different mesh openings (90, 100, 110 mm) in which the netting is turned 90° to the direction of tow (T90). Results for the regulated codend showed that there was little size selection, catching greater than 97% of redfish over all of the length classes observed. Considering the fished population, the smallest T90 codend would catch 30% fewer redfish under the minimum landing size (MLS) of 22 cm compared with the T0 codend, but would also lose 16% of catch above 22 cm. The T90 codend with 100 mm mesh opening had the same size selectivity as the smallest T90 codend. The 110 mm T90 codend would catch 50% less redfish below MLS but lose 40% of redfish above MLS. Overall, results show that T90 codends improve size selectivity in which large proportions of undersized fish are successfully released.