SPATIAL AND TEMPORAL AVAILABILITY IN THE MULTISPECIES CRUSTACEAN TRAWL FISHERY ALONG THE EAST-COAST OF SOUTH-AFRICA AND SOUTHERN MOZAMBIQUE, 1988-1993

Catch and effort data from the crustacean trawl fishery along the east coast of South Africa and southern Mocambique are used to investigate spatial and temporal availability of several commercially important crustacean species. The abundance of shallow-water prawns, Penaeus indicus, Metapenaeus monoceros and Penaeus monodon, on the Tugela Bank trawling grounds is strongly seasonal, increasing from January to June, and declining towards September. Decreasing annual catches are related to low rainfall in selected river catchment areas. Deep-water trawling between 100 and 600 m deep captures the pink prawns Haliporoides triarthrus and Aristaeomorpha foliacea, the langoustine Metanephrops mozambicus and Nephropsis stewarti, the rock lobster Palinurus delagoae and the deep-sea red crab Chaceon macphersoni. Trawling effort is distributed over depth and season according to species availability and economic value, the most valuable species mix being found at 400-500 m. Langoustine, optimally fished for at 300 - 400 m, and rock lobster, optimally fished for at 100-300 m, have increased in importance as shallow-water prawn catches have declined.