Resource segregation among iliophagous fish in Lake St. Lucia,Zululand

Synopsis Sarotherodon mossambicus, Chanos chanos and 11 species of Mugilidae occur in Lake St. Lucia, Zululand. All are iliophagous and potential competitors. This investigation shows that although their diets overlap, competition is reduced by different feeding mechanisms which apparently result in the available food items being consumed in differing quantities. The diet of C. chanos consists chiefly of microfauna, that of Mugilidae microflora associated with sand grains and that of S. mossambicus, microflora associated with filamentous algae and benthic floc. Potential competition is also reduced because C. chanos reach peak numbers in summer whereas Mugilidae are more abundant in winter.