Seasonal changes in the species composition of penaeid prawns on the Tugela Bank, Natal, South Africa

Abstract

This study investigated the species composition of different size categories of penaeid prawns collected between 1988 and 1990 from the Tugela Bank off the east coast of South Africa. Penaeus indicus dominated the catches, followed by Metapenaeus monoceros and Penaeus monodon in order of decreasing abundance. In the large size categories, species composition did not change seasonally and catches were made up entirely of P. monodon or P. indicus. Seasonal fluctuations between species were more prevalent in the small size categories, which consisted of P. indicus and M. monoceros. From January to July catches were dominated by P. indicus and thereafter by M. monoceros. In the smaller size categories, two peaks in catch per unit effort were identified. The first (January–May) and second (July–September) peaks were ascribed to the predominance of P. indicus and M. monoceros respectively.