This study was carried in Ceará Mirim River, State of Rio Grande do Norte, Brazil. At this location, the river shows high water transparency and predominance of aquatic macrophytes in the margins. This study aims to describe the feeding habits and verify the presence of feeding overlap in the diet of four sympatric species of Cheirodontinae: Compsura heterura Eigenmann, 1915 (n= 452), Serrapinnus heterodon (Eigenmann, 1915) (n= 473), S. piaba (Lütken, 1875) (n= 509) and Serrapinnus sp. A (n= 313). The specimens were collected monthly, from April 2001 to April 2002, using seine nets. The stomach contents were analyzed using the frequency of occurrence, percentage composition and an alimentary importance index. The feeding overlap was calculated through the index of Morisita between pairs of species. The species did not showed seasonal variation in the diet. Algae, vegetal matter, microcrustaceans and autochthonous insects were predominant in the species diet. Serrapinnus heterodon and Serrapinnus sp. A presented omnivorous feeding behaviour, while C. heterura and S. piaba showed omnivorous feeding behaviour with tendency to herbivory. In addition, the species showed high feeding overlap due to the consumption of similar items. These results suggest that food resources are abundant and enough to be partioned by these four omnivorous sympatric species.
Northeast Brazil; omnivory; feeding overlap; fishes
