Pequena central hidrelétrica afeta a estrutura populacional do Lambari do Rabo Vermelho, Astyanax aff. fasciatus

Abstract

Recently in Brazil began to be built small hydroelectric plants on small rivers order to increase energy capacity. The São Francisco real river was barred to form the reservoir of PCH São Francisco. The aim of this work was to verify if the reservoir of PCH São Francisco, changed the population structure of Astyanax aff. fasciatus. Quarterly samples of fish were held at three sampling sites, with gillnets, in phases before and after the filling of the reservoir. Significant differences were observed in the abundance in the reservoir and downstream sites. In size structure, higher frequency of smaller individuals downstream and into the reservoir, after the formation of this. With respect to reproductive activity, there was a reduction of the intensity in the reservoir in the period immediately after the construction of the dam. As for the condition factor in the reservoir and downstream were observed positive changes. Therefore, we conclude that the PCH São Francisco influenced positively the abundance and size structure and the condition factor of A. aff. fasciatus, which is related to the greater availability of food and habitats after the construction of the dam.