Geographical colour variation in cichlid fishes at the southern end of Lake Tanganyika

Geographical colour variation and distribution of 48 common cichlid fish species were studied at 20 sites along an 85 km shoreline at the southern end of Lake Tanganyika, Africa. Sixteen species had two or more colour morphs and 11 species showed a limited distribution in the study area. They were all rock-dwellers. Distributional borders of the color morphs and species with a limited distribution mostly lay in two long sandy beaches, 7 and 13 km long. We suggest that the long sandy beaches can be effective barriers against dispersal of shallow-water rock-dwelling cichlid fishes.