Food resource sharing and partitioning among some fishes of the Pongolo River floodplain

Abstract

The diets of 12 fish species which coexist in the Pongolo floodplain lakes were determined from an analysis of the contents of 3 691 stomachs collected over a period of 12 months. Although almost all species were found to feed on a variety of foods, with consequent dietary overlaps, quantitative analysis of the results showed that distinct preferences for specific food types considerably ameliorated the effects of such overlaps. Partitioning within the major food categories, differences in relative population sizes, spatial and temporal differences in feeding and shifts in diet following inputs of seasonally occurring foods, all tended further to reduce effective competition between species. The results are discussed in the broader context of colonization of the Pongolo system by a tropical fish community in circumstances where the principles of island biogeography may be expected to apply.