Ecomorfologia, morfometria e alimentação de peixes da reserva de Itamacaoca, bacia do rio Munim, leste maranhense

Abstract

The freshwater ichthyofauna of the Neotropical region is the most species-rich of the world, comprising more than 6.000 described species, and it is estimated that this number could reach more than 9.000 described species in the next years. Within this megadiversity, small fish have an expressive abundance, correspondente a 70% ichthyofauna of Neotropical region. The Mata de Itamacaoca is one of the few protected urban areas in the Upper Munim River Basin, State of Maranhão, Brazil. Although, the Upper Munim River Basin is one of the main drainages of Hydrological Unit of Maranhão, there are few published studies focusing on ichthyological surveys and taxonomic works of this basin. In the face of this gap, this study proposed to provide an inventory and analyze morphological and trophic patterns of the fish community of Mata de Itamacaoca, Upper Munim River Basin. The sampling was conducted in five collection sites distributed within the limits of Mata de Itamacaoca, Upper Munim River Basin. A total of six orders, 13 families and 23 species of fish have been found, the order with the greatest species richness, considering all the excerpts, was Characiformes followed by Cichliformes. There were no invasive alien species collected in the study area. 10 species showed negative allometric growth. The population of Nannostomus beckfordi, the most abundant species in the area, presents some evidence of stable ecological strategies in terms of ecomorphology related to stations and flow rate. Morphological variations in conjunction with the availability of resources determined dietary differences, as well as the trophic profile of the fish community of Mata de Itamacaoca. Finally, the results show the importance of the integrity of aquatic ecosystems for trophic and ecomorphological structuring of ichthyofauna and provides information that can contribute for comparison with other untouched environments and for evaluation of disturbed streams.