The Diet of Five Cichlid Fish Species from Lake Kariba, Zimbabwe

Abstract

The diet of five cichlid fish species from the littoral areas of Lake Kariba was investigated in 1996-97. Serranochromis macrocephalus, Pseudocrenilabrus philander and Pharyngochromis acuticeps fed mostly on calanoid copepods, chironomid larvae, rotifers, phytoplankton and fish fry. Oreochromis niloticus and 0. mortimeri fed mainly on detritus mixed with diatoms. There was no ontogenetic dietary shift in fish between 20-70 mm in length for any species. A dietary overlap existed between the omnivorous species S. macrocephalus, P. philander and P. acuticeps, and between the microphagous species 0. niloticus and 0. mortimeri. There was no difference in gape width between P. acuticeps and P. philander and competition between them may be reduced by their habitat preferences while S. macrocephalus only competes with them as juveniles since adults switch to a piscivorous diet. Direct competition between species 0. niloticus and 0. mortimeri may result in the exclusion of the latter. The diets of P. acuticeps and P. philander have changed since the 1970s reflecting the influences of Salvinia molesta that was widespread at that time


Transactions of the Zimbabwe Scientific Association Vol. 74 2000: 16-21