ICHTHYOFAUNA FROM HEADWATER STREAMS OF THE ARAGUAIA AND DAS MORTES RIVER BASINS, MATO GROSSO, CENTRAL BRAZIL

Ichthyofauna of the headwaters of the upper Araguaia River basin

Abstract

The Neotropical freshwater ichthyofauna is the world’s richest, and its considerable diversity has been molded by a variety of processes at both local and regional scales. Despite this diversity, the biota of many aquatic environments is still poorly known, particularly in the headwater tributaries draining the central Brazilian Plateau. The aim of this study was to analyze the species richness, species composition, and abundance of the fish assemblages from the southern and northern drainage basins of the Serra Azul State Park and Serra do Taquaral in southeastern Mato Grosso (Brazil), which form part of the upper Araguaia River basin, including tributaries of the Araguaia and das Mortes River subdrainages. A total of 5,083 fish specimens were captured, representing six orders, 20 families, 52 genera, and 77 species. In total, 15% of the species were exclusive to the Araguaia River basin and 51% were exclusive to the Rio das Morte basin, with 33% of them common to both drainages. Neither the environmental variables nor the species richness and abundance varied significantly between the two subdrainages, although the species composition was mostly distinct between them.