STUDIES ON THE VIABILITY OF INTRODUCTION OF A GILLNET FISHERY FOR MINOR CYPRINIDS IN RESERVOIRS

Abstract

The exotic Oreochromis mossambi cus (Peters) accounts -for about 80“/. of the inland fish production in Sri Lanka at present. The bulk of the production comes from the capture fishery in reservoirs and is mainly based on the monospecific gill net fishery. The indigenous species represented in the commercial catches are mostly limited to Barbus sarana, and in certain reservoirs Labeo dussumieri also occur in catches. However, apart from these species there is a large population of minor cyprinids in perennial reservoirs,which remain untapped at present. The indigenous minor cyprinids could be broadly categorised into two groups depending on the catchability by gill nets of 15mm range and 30mm range respectively. These minor cyprinids essentially inhabit the deeper areas of the water bodies as the adult population of 0. mossa.mbi cus. The minor cyprinid fauna, differed marginally from reservoir to reservoir. The main species of minor cyprinids that were present are B .sarana, B .dorsali s ■«* B. cho 1 a . B. f i 1 amentosus , Ambl ypharynaodon mel ett i nus and Rasbo’-a dan i coni ous. Thus with the use of the two categories of gill nets viz. 15mm and 30mm range, the minor cyprinids could be harvested without any detrimental effect on the Q.mossambi cus fishery. The possibility of introduction of a small meshed gill net fishery for minor cyprinids is based on detailed analysis of catch curves of each minor cyprinid species.