Relative size selectivity of a four-panel codend with short lastridge ropes compared to a flexigrid with a regular codend in the Barents Sea gadoid trawl fishery

Size-selective grids in the Barents Sea trawl fisheries have demonstrated large variation in sorting capacity. When combined with dynamic catch-control systems for regulating catch quantity, surplus fish are washed out at the surface. The objective of this study was to develop a codend concept that releases more undersized fish than the most commonly used size-selectivity device in the Barents Sea trawl fishery (flexigrid combined with a two-panel 130 mm codend). Fishing with twin trawls, a four-panel 153 mm codend concept with short lastridge ropes to force open meshes was compared with a flexigrid combined with a 130 mm mesh codend, in terms of size selectivity for cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and saithe (Pollachius virens). Compared to the grid-codend setup, the four-panel codend with short lastridge ropes retained about half of 54.5-59.4 cm gadoids, with catches of undersized cod, haddock and saithe reduced by 90 (ci = 85-94), 92 (ci = 88-96) and 86 % (ci = 79-92) respectively. The study demonstrated that the four-panel codend concept releases more undersized fish than the flexigrid-codend combination.