Fish diversity in three tributaries of the São Francisco river, Brazil

Abstract

We evaluated fish diversity in three tributaries of the São Francisco River, one of the largest watercourses in Brazil. The study site is in the sub-basin of the Carinhanha River [Carinhanha, Cocos (I and II) and Itaguari Rivers], located in the South region of the Bahia state. These rivers are crossed by bridges of the federal highway BR-135. After sampling, upstream and downstream from each bridge, during drought and rain seasons, 3,520 specimens of fish (57 species, 21 families) were captured. The species with highest occurrence were Astyanax cf. taeniatus, Serrapinnus heterodon, Astyanax bimaculatus and Astyanax cf. rivularis. During drought season, the number of specimens captured was higher, leading to an increase of species dominance. In the rainy season, species diversity was higher with a greater distribution of individuals among species. The data indicate the maintenance of the fish faunal structure despite anthropogenic activities on the studied areas.