Study of the effect of a By-catch Reduction Panel in a twin-trawl on reducing plaice discards

Comparative fishing trials were conducted in November 2008 on the euro-cutter MFV TH-7 “Adriana Maria” on fishing grounds in the North Sea to investigate the effect of By-catch Reduction Panels inserted in a twin-trawl. In a total of 17 experimental hauls two nets were fished simultaneously, a conventional net on the starboard side and a net with a By-catch Reduction Panel inserted in the top sheet on the port side. The codend meshsize used was 80 mm. The main target species is plaice (Pleuronectes platessa L.). The By-catch Reduction Panel (BRP) tested was a square mesh panel with: 25 bars across and 22 bars deep of mesh size 150 mm, euroline™ single braid of 5 mm thickness. The panel was built in surrounding 80 mm netting and joined to 38 meshes in width and 19 meshes in depth in the port net of the twin-trawl, 12 meshes deep in front of the joining round of the codend. The panel reduced the by-catch of juvenile plaice by some 20% compared to the conventional net, but there may be a loss of marketable plaice. However, commercial losses were not confirmed by the skipper when regarding earnings over a longer period. When plaice discards are expressed as a fraction of total catch the differences were not found to be significant.