A comparative analysis of legislated and modified Baltic Sea trawlcodends for simultaneously improving the size selection of cod (Gadus morhua) and plaice (Pleuronectes platessa)

• Published in: Fisheries Research
• Main Authors: Wienbeck, Harald, Herrmann, Bent, Feekings, Jordan P., Stepputtis, Daniel, Moderhaak, Waldemar
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Gadus morhua
• Online Access: https://orbit.dtu.dk/en/publications/4f3d21fe-e673-41aa-9de3-a7e4b3ac91bb; https://doi.org/10.1016/j.fishres.2013.10.007

Five modified trawl codends were assessed for their utility in simultaneously improving the size selectiv-ity of cod (Gadus morhua) and plaice (Pleuronectes platessa) in the Baltic Sea. The modifications includedrefining the selective performance of the current Bacoma codend by increasing the mesh size of thelower panel from 109 mm double twine to 129 mm single twine and increasing the mesh size in theupper square mesh panel from 132 to 147 mm, and also making the lower panel the same design as theupper panel; i.e. a full square mesh codend. These three experimental designs were tested in conjunc-tion with the currently legislated codends; Bacoma and T90. The most favourable selective propertieswith regard to simultaneously improving the selectivity for round and flatfish, considering the currentminimum landing sizes (MLS) for cod (38 cm) and plaice (25 cm) in the Baltic Sea and the fish populationsize structures during the sea trials, were found to be the T90 codend and the Bacoma codend with amodified lower panel. For the T90 codend, the selection parameters (L50 and SR) were 43.4 and 6.7 cmfor cod, and 24.7 and 2.1 cm for plaice. The selection parameters for the most effective modified Bacomacodend were 41.1 and 8.3 cm for cod and 25.2 and 3.9 cm for plaice