Catálogo ilustrado de peixes do Rio Comandaí no Município de Guarani das Missões (Rs, Brasil)

Abstract

Fish constitute a key component of aquatic communities in the complex functioning of ecosystems. Despite this, there are innumerable gaps in their biological knowledge, including the occurrence in identifying the species in their environment. With the purpose of knowing more about the icthyofauna of the region of the Missions, this work had as objective the creation of an Illustrated Fish Catalog for the Comandaí River (RS, Brazil). For the preparation of the catalog, monthly collections were carried out for a period of one year, which were carried out from March 2016 to February 2017, at seven points along the river, representing the middle stretch of the river. In order to collect the fish, seven nets were used: five hammocks (1.5, 2.0, 2.5, 3.0 and 4.0 cm), 10 meters long and 2 meters high, one witch net (triple mesh 3.0) and a trawl net (10,0 m mesh). The collected samples were fixed in 4% formaldehyde, and the biometry and identification were done later in the laboratory of the Federal University of the frontier South-campus Cerro Largo (UFFS). In the present study, 370 adult fish belonging to five orders, 15 families and 33 taxa were captured. The order that presented the largest number of species was Characiform, with 14 taxa, and the species with the highest density of fish were the whipworm Loricariichthys anus (133 individuals), lambari Astyanax aff. fasciatus (91 individuals) and steindachenerina brevipinna (22 individuals). Most of the fish caught belong to small and medium sized individuals. The months that presented the largest number of samples collected were September (53 individuals) and August (45 individuals). The creation of this catalog could serve as a basis for new studies on fish fauna in the rivers of the northwest region of the state of Rio Grande do Sul (Brazil), helping to disseminate knowledge about diversity, demonstrating the ecological and economic potential that rivers have and still environmental conservation actions.