Ictiofauna do Rio Capivari no trecho compreendido entre o município de Cruz das Almas e a foz no Rio Paraguaçu, região de São Félix, BA

Abstract

This study aimed to survey the fish fauna from Capivari river, a small tributary of the Paraguaçu basin at five points along a stretch, between the Cruz das Almas and the mouth in Paraguaçu estuary. Two thousand and sixty-nine fish, distributed in 10 orders, 18 families, 24 genera and 30 species, we collected. Orders Perciformes, Pleuronectiformes and Characiformes were more representative. There was an increase in the richness toward to the mouth, which is in accordance with the predicted for Neotropical rivers. The species richness ranged from 7 in points upstream to 16 in those near the mouth. In four points were the prevalence of exotic poeciliid, P. reticulata and P. vivipara, which led to low diversity and evenness values, and high dominance for these points. This can be explained by the fish’s tolerance to environmental adversity, his opportunism and subsequent success in relation to native species. The results agree with other studies that record the predominance of poeciliid. They also demonstrate that despite the degradation, the richness in Capivari remains high. However, much of that richness is due to the contribution of the Paraguaçu estuary, with species that access the estuary for breeding. This demonstrates the importance of Capivari to maintain the integrity of regional fish communities.