Preliminary appraisal of Antarctic fish selection by the 32/36 bottom trawl combined with various codends
Selectivity properties of single and doubler-layer twine codends (mesh size 120 mm) and single-layer tape codends with a mesh size of 60 and 100 mm were determined. It was found that the selectivity properties of twine codends are unsatisfactory in the case of Antarctic icefish, bumphead notothenia, and Scotia Sea icefish. This was primarily caused by the heavy net material used for their construction, incorrectly chosen mesh size, and certain morphological features of some Antarctic fish, which make it difficult for them to escape from the codend. Selectivity properties of both tape codends were much better. It was found that an optimum mesh size of this codend for selection of Antarctic icefish and bumphead notothenia ranges from 60 to 100 mm. For other Antarctic fish, especially Scotia Sea icefish and South Georgia icefish the determination of a proper mesh size of trawls used in fishing for them requires further research. It should first of all cover twine codends with a mesh size of 80 mm, currently used on factory trawlers, as well as codends with a structure resembling tape codends.