CARACTERIZAÇÃO DA ESTRUTURA DAS ASSEMBLEIAS DE PEIXES DO ALTO DA BACIA DO RIO CORUMBÁ, GOIÁS, BRASIL CENTRAL.

Abstract

The present study aims to characterize the fish assemblage structure of the Corumbá River and its main tributaries (Areias, Descoberto, Alagado and Antas rivers), located in the south-center region of Goiás State. The samples of ichthyofauna were carried out bimonthly, between September 2002 and April 2009. Fish were caught using gill nets with distinct meshes during ten consecutive days, remaining in each sample stretch during 48 hours. In the Corumbá River basin 9,243 specimens were captured and we recorded a richness of 90 species, with predominance of Prochilodus lineatus, Astyanax altiparanae and Cichla ocellaris. The rarefaction analysis showed a higher richness for the Corumbá and Antas rivers (28 and 24 species, respectively), and the index of similarity (Morisita-Horn) did not indicate spatial variation in the distribution of the fish assemblages. The correspondence analysis indicated that the invertivore trophic guild is very expressive and mainly associated to tributaries. Other expressive trophic guilds were the piscivores, detritivores and omnivores. These results indicate that the fish assemblages of sampled rivers presented similarities amongst them in terms of composition but not richness. Additionally, there is predominance of some trophic guilds that seem associated to species dispersal patterns influenced by the presence of the dam at the main channel of the Corumbá River.