Variabilidade genética da Dourada na Bacia do Rio Branco (Brachyplatystoma rousseauxii-Siluriformes:Piemlodidae), na bacia do rio Branco, Roraima, Amazônia brasileira

Abstract

Dourada is one of the largest catfishes exploited in the Amazon region. Five countries exploit this resource, which is considered, by several authors, as a unique population with seasonal migration, occurring in the whole basin, using distinct areas for reproduction, feeding and growth. Ecological or genetic data about this specie in Roraima are unknown. The specie is largely exploited by fishing, mostly in the wet season in the Rio Branco basin (May to September). Production in Roraima is about 27 tons annually. This study had as objective to estimate the genetic variability of the douradas (Brachyplatystoma rousseauxii) from the Rio Branco basin and verify the existence of genetic correlation between these and other populations (or sub-populations) studied in the Amazonian basin. For this study, 54 individuals of dourada was collected from Caracaraí fishermen, which was extracted the total DNA, and analyzed the nucleotide sequence of the mitochondrial DNA controlled region. These nucleotides sequences were used in analyses of polimorphism of DNA, philogenetics and AMOVA. Forty-four haplotypes had been identified, being 43 singletons. The population and philogenetics analyses demonstrated that there is not genetic segregation inside the analyzed individuals of dourada. Therefore, the study outcomes indicate that the douradas collected in the Rio Branco are from the same panmitic population that uses the whole Amazonian basin to complete its life cycle, corroborating other authors.