QUALIDADE DO AMBIENTE AQUÁTICO E INTERAÇÃO COM AS ASSEMBLEIAS DE PEIXES EM CURSOS D ÁGUA DA BACIA DO RIO ARAGUAIA EM GOIÁS, BRASIL CENTRAL.

Abstract

This study was conducted in 31 tributaries (13 rivers and 18 streams) from the Araguaia River in Goiás State during the dry season, aiming to evaluate the aquatic environmental quality and examine the fish-habitat relationship taking into account limnological variables directly related to pollution of water courses (total phosphorus, nitrate, chlorophyll a , dissolved oxygen, pH, turbidity and heavy metals Cd, Cr, Mn, Pb and Zn). Total phosphorus concentrations were significantly different among streams, and nitrate concentrations among rivers and streams. High level concentrations of total phosphorus were mainly located in the center of the studied watershed. Results suggest a negative correlation between the classes of trophism and concentrations of nitrate. With a few exceptions, considering pH, Mn, and Pb, streams could be classified at Class 3 according to CONAMA s reference values. Coinertia analysis suggests that total phosphorus, dissolved oxygen, pH, turbidity, Cd, Mn, and Zn influenced fish assemblage composition. Overall results of this study indicate that the degree of pollution influenced the currently observed fish distribution in the Araguaia River Basin.