Ichthyofauna of Serra do Divisor National Park, upper Rio Moa, Rio Juruá basin, Acre State, Brazil

Resumo

Abstract The Serra do Divisor National Park (PNSD) is situated in the far western portion of Brazil, in the state of Acre, on the watershed divide between the upper Rio Juruá basin, in Brazil and the middle Río Ucayali basin in Peru. The Rio Juruá is one of the longest tributaries of the Amazon basin, and most of its headwaters originate in the Serra do Divisor, including the Rio Moa, the main tributary of Rio Juruá in Acre. Surveys of the ichthyofauna of the PNSD were not conducted during the preparation of the management plan, and the fish diversity of this protected area remains largely unknown. Here, we report the results of an expedition to the northern section of the PNSD, aiming to increase knowledge of the ichthyofauna of a poorly known region whose protected status is currently under threat. Seventeen localities in the upper Rio Moa drainage, in the surroundings of the region known as Pé da Serra (between 73°38’04.7” W and 73°44’52.7” W, and 07°26’52.2” S and 07°32’ 14.7” S), were sampled using hand nets and beach seines. Sampling was conducted at sites along the Rio Moa, its tributaries, and adjacent lakes. A total of 3,504 specimens were collected, representing 103 species in 89 genera and 27 families across seven orders. The Characiformes (52 species) and Siluriformes (32 species) were the most diverse orders, followed by the Gymnotiformes (8 species), Cichliformes (8 species), Batrachoidiformes (1 species), Cyprinodontiformes (1 species), and Synbranchiformes (1 species). Species of Characiformes, Siluriformes, and Cichliformes were found in all three sampled environments. Gymnotiformes and Batrachoidiformes were not recorded from lakes, and species of Synbranchiformes and Cyprinodontiformes were found exclusively in tributaries of the Rio Moa. Six species represent new records for Brazilian drainages, 13 for the Rio Juruá drainage, and 30 for the Rio Moa. The identification of 43 species requires additional, more detailed studies. For most species, information on the variation of diagnostic characters is provided, which, together with images of selected specimens, is intended to serve as a basis for future studies of the ichthyofauna of the PNSD.