An investigation of seasonal and annual catches and discards of the Dutch pelagic freezer-trawlers in Mauritania, Northwest Africa

Abstract

The coastal waters of Northwest Africa (Morocco, Mauritania, Senegal) support a large fishery on small pelagic fish. Super-trawlers from the European Union, mainly of Dutch origin, have exploited these resources since 1996, in particular off Mauritania. This paper reports on the catch and discarding of targeted small pelagic fish by these super-trawlers, based on the results of an independent observer programme that covered 16% of the fleets¿ fishing trips during the period 1999¿2003. Throughout this period, the average total catch and effort of the fleet was approximately 176,000 t and 1720 days at sea per year, respectively. The target species were Sardinella aurita, Sardinella maderensis, Sardina pilchardus, Scomber japonicus and Trachurus trecae representing an annual average of 94% by weight of the total catches. An alternating seasonal pattern of abundance in the catches was shown for S. aurita (dominant during summer) and S. pilchardus (dominant during winter). The amount of discards on average was less than 10% of the total catch by weight and consisted mainly of commercial species. There was no size selective discarding for the five target species and seasonal changes in discarding were only detected for S. pilchardus. This study suggests that there was no wide scale discarding of pelagic fish by the European super-trawlers from fisheries off Mauritania between 1999 and 200