Effects of changes in the size and shape of codend on catch of Aegean Sea fishes

In the present study the retained proportion and the mean individual weight was compared for 61 marine demersal species caught with three different trawl codends: the 14 mm (bar length) diamond mesh (14 D) (presently used in the Hellenic commercial trawl fishery), the 20 mm square mesh (20 S), and the 20 mm diamond mesh (20 D). The experiments took place at 12 stations in the western Aegean Sea in October 1993 and March 1994. The results indicated that: (1) 20 D and 20 S allow significantly more individuals to escape through the meshes; and (2) the mean weight of the retained individuals for 20 D is significantly larger than those for 14 D and 20 S. Thus, the banning of 14 D codend from the fishery seems to be essential for the rational management and conservation of the Hellenic demersal resources.