Genetic variability and population structure of Osteoglossum bicirrhosum (Osteoglossiformes: Osteoglossidae) in the Amazon basin

Abstract This study tested the hypothesis that the silver arowana from different rivers in the Amazon basin is genetically structured, thus requiring differentiated management strategies to maintain stocks and continue economic activities. Such activities include artisanal fishing for food and predatory fishing for ornamental purposes, which has a major impact on the populations of the species, as it involves the death of adult males to capture the fry. Thus, the mitochondrial ATPase 6 gene of 397 silver arowana individuals was partial sequenced to analyze the genetic diversity. The results show that the genetic variability is greater in populations occurring to the west of the Amazon basin, suggesting that the origin of this diversity occurred in western Amazonia, with subsequent dispersal to the east of the basin. The observed population structure was oriented from west to east, likely due to isolation by distance. Therefore, these populations need to be managed and conserved in a differentiated and effective way, to preserve their local genetic characteristics. It is important to think about the short-term management of these populations, implementing conservation measures, such as fisheries management, specific legislation for the species and increased monitoring to prevent fishing for ornamental purposes during the species’ reproductive season.