Damage to selected fish species escaping from prawn trawl codends: a comparison between square-mesh and diamond-mesh

A study to examine damage to fish escaping from prawn trawl codends was carried out in tropical Australian waters of the Gulf of Carpentaria and is the first of its kind in Australian or tropical fisheries. Fish passing through two sizes of square meshes (38 mm and 45 mm) were compared with fish passing through the standard 45 mm diamond-mesh codend. Escapees were captured in a fine mesh (16 mm) codend cover and brought on board in a water-filled scoop into which the fish were released. Individuals of species selected for damage assessment were placed in a lethal dose of MS222. These fish were examined for damage. Five species were collected in sufficient numbers ( n>10) for statistical analyses to be carried out. The results indicate that, fish escaping through either 45 mm codend mesh have minimal damage. Those fish escaping through the 38 mm square codend mesh incurred more severe damage than those escaping from the 45 mm diamond-mesh codend.