The aquatic biota of the Paraná river basin has been impacted by several dams. This study aimed characterize and compare seasonally the fish feeding of Grande river fish fauna, downstream from Itutinga Power Plant. In this river stretch it is expected the reduction of seasonal effects due to flow regulation. Data collection was conducted in January and July 2010 with gill nets and trawls. The fishes were fixed in formalin and preserved in alcohol for stomach contents analysis. The diet was characterized by Feeding Index (IA) and the guilds each species belongs was determined by the χ² test. The feeding of each species and the occurrence of food items were compared in periods of drought and rain using nMDS and SIMPER analysis. We analyzed 809 stomachs from 32 fish species categorized in piscivorous, herbivorous, ilyophagous/detritivorous, ilyophagous, algivorous, frugivorous, invertivorous and generalists guilds; the generalists had the highest species richness. The nMDS indicated lower diet diversification in July, when it was observed an increase of plant, invertebrate and sediment occurrences. However, differences in diet were lower than expected. This study expanded knowledge about fish feeding habits and local dam effects on species diet as a result of flow regulation.
Reservoir; feeding habit; tropical fishes; diversity
