Selectivity of standard Polish commercial trawl codends on Antarctic fishing grounds
Abstract / Description:
Selectivity studies were carried out for two types of steelon codends used in commercial fishery, with a nominal mesh size A = 80 mm and A = 100 mm, made of double twines with a thickness of 4.2 mm. The studies covered 6 major fish species.
- It appears from the study that Antarctic icefish and bumphead notothenia are subject to selection during trawling, although the effectiveness of this process - especially in the latter case - is not satisfactory.
- Scotia Sea icefish, Chaenodraco wilsoni, and Chionodraco rastrospinosus exhibit a lower tendency to pass through meshes of the codend than Antarctic icefish and bumphead notothenia.
- The solution to the problem of ensuring selectivity of codends at a sufficiently good level seems possible as a result of the application of webbing with permanently open meshes for codend construction.
- The most difficult matter will be preparing a codend with proper selectivity properties for South Georgia icefish, because this species exhibits the smallest tendency to escape during the trawling among all the species studied.
Conclusions and observations were in some cases based on a relatively small amount of experimental material.
Further investigations of this problem are necessary since producing selective trawl gear for harvesting Antarctic fish seems crucial from the point of view of conservation of living fish resources on those fishing grounds.