Contribution to mechanical forcing of opening of meshes in trawl codends
Bulletin of the Sea Fisheries Institute 1 (140) 1997, pp. 59-65

Marian Szatybełko
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: cod, trawl, codend, selectivity, hydromechanics.

The research relates to the issue of the selectivity of cod trawl codends and verifies the conception of the opening of meshes in the netting of codends by using ropes with selected mechanical properties. For this purpose, an experimental codend had been made, which underwent  exploitational tests with the use of a set of selectivity tests on cod trawl codends. The tests have confirmed the assumptions of the conception: the experimental codend, though it requires further technological and constructional improvements, exhibited the required selectivity. With mesh bar length in the codend equal to 60 mm, L50 equals 35 cm, which corresponds to the minimum legal length of cod being currently in force.