By-catch and Discarding in Pelagic Trawl Fisheries

Incidental mammal catch and the composition of the fish catch were studied in pelagic trawl fisheries in the North-East Atlantic. Several seasonal European fisheries were investigated with scientific observation on the fishing vessels. A total of 379 days at sea were observed . The sampled fisheries were horsemackerel (Dutch, French), herring (Irish), mackerel (UK), pilchard (UK , French) and other French fisheries (hake, tuna, bass, black bream, anchovy). Unintentional catches of dolphins were recorded in four of the investigated fisheries (Dutch horsemackerel, French tuna, French hake and French sea bass) at a rate of 1 dolphin per 100 tow hours; Grey seals were caught in the Irish herring fishery at a rate of 4 individuals per 100 tow hours. The fish catches showed a high selectivity in several pelagic fisheries with a low discard rate ( 20 % by weight of the total catch) and a high percentage of the target species ( 50 % by weight) in the catch. However in some fisheries poor selectivity was observed particularly in the French hake fishery (with discards equal to 50 % of the total catch) and in the French black bream fisheries where legal targeted individuals amounted less than 30 % by weight in the total catch. This might be improved by appropriate technical measures such a minimum mesh size appriopriate according to the target species. Length compositions of discarded and landed fish are provided for future utilisation in Working groups.