Selectivity experiments with square mesh codends in bottom trawl

Abstract

During selectivity experiments with square and diamond mesh codends, an\nevaluation of the covered codend method and a modified trouser trawl\nmethod went in favour of the last one. Both twisted knotless- and\nbraided knotted material was used for the experiments. Square mesh\ncodends gave higher 50% retention lengths and selection factor than the\ndiamond mesh codend, both for cod and haddock. Fished commercially, the\nsquare mesh codend of knotted netting caught fewer undersized fish than\nthe diamond mesh codend. Big bycatches of redfish caused heavy meshing\nin the square mesh codend and reduced the selectivity. Due to the fixed\ncircumference of the square mesh codend some problems arose when\nemptying big hauls on a sterntrawler.