Population structure and diet aspects of Pimelodella transitoria (Siluriformes, Heptapteridae) in streams of the Itanhaém River Basin, SP Michele Andriaci Ferreira do Carmo, Ursulla Pereira Souza

Abstract

 Pimelodella transitoria has a body with bare skin, mucus and dermal plaques. To assist in its management and conservation in the Itanhaém River Basin, the present study analyzed 22 specimens of P. transitoria in order to provide more accurate information on the population structure and diet of the species. After collection with an electrofishing gear, the fishes were measured, weighed and dissected in the laboratory. The sex ratio was calculated by X², the average length of males and females by the Student t test and the diet was analyzed by the Food Preference Degree (FDP). The sex ratio did not differ from 1:1 (x² = 2,571; df = 1; p = 0,109) and there was no difference between the average length of females and males (t = 1,35, df = 12, p = 0,4). Pimelodella transitoria showed mainly insectivorous diet, with higher values for FDP native immature insects