FISH DISTRIBUTION IN RELATION TO TURBIDITY GRADIENTS IN A MAN-MADE LAKE, STERKFONTEIN DAM (SOUTH-AFRICA)

The objective of the study was to investigate the distribution of fish in relation to turbidity in Sterkfontein Dam. Oncorhynchus mykiss was found mainly in the limnetic zone of the clear-water section of the r eservoir (10 NTU in 80% of the surface area). Barbus aeneus and Labeo capensis were caught predominantly in the most turbid area (mean 28.32 NTU). Labeo umbratus and Clarias gariepinus preferred a sheltered, we ll-vegetated bay in the clear-water area. Total catches indicated that turbidity pattern found in the reservoir did not influence the distri bution of indigenous fish species. Other factors such as availability of breeding and feeding habitats were probably more important.