The fish assemblage in a stretch of Tibagi river was studied during the period of one year, throught monthly sampling. It was observed that four fish species (Schizodon intermedius Garavello & Britski, 1990, Acestrorhynchus lacustris Reinhardt, 1874, Pimelodus maculatus Lacépède, 1803 and Steindachnerina insculpta Fernandez-Yepez, 1948) were very frequent and they represent all the main trophic groups. In order to characterize feeding activity, fat storage and reproduction the means degree of repletion, fat and maturation, obtained for each species in each month were compared among the four fish species. Steindachnerina insculpta, a detritivovous species was the one with the highest feeding activity while A. lacustris, a piscivorous fish, showed the lowest feeding activity. For these two species it was clearly observed a sequence of events: higher feeding activity followed by higher fat storage followed by reproduction, that was not observed for P. maculatus and S. intermedius. The variations in feeding activity and fat storage showed by P. maculatus and S. intermedius might be related to their diets.
Fish; feeding activity; gonadal development; Tibagi river; Paraná