Diversidade genética e conectividade do tubarão martelo Sphyrna lewini de um grande estuário do nordeste do Brasil

Abstract

Sphyrna lewini is one of the three large species of hammerhead sharks that have a global distribution and undertake long migrations. This species uses estuarine zones as a mating and feeding ground. Some aspects of S. lewini genetics are known, but no study investigated juveniles of estuarine zones in the south Atlantic and their possible connection with other parts of this ocean, including insular ecosystems. Based on this the main goal of this study was to characterize the genetic structure of juveniles of S. lewini of an estuarine complex in northeast Brazil. A total of 27 samples of S. lewini were obtained, where 22 came from an estuarine zone (Sergipe and Vaza-Barris rivers estuary, Sergipe state) and five came from the Saint Peter and Saint Paul Archipelago (SPSPA), an oceanic archipelago located between Brazil and Africa. These samples had their DNA extracted and the control region of mitochondrial DNA partially sequenced (699 bp). Homologous DNA sequences obtained from S. lewini samples from other regions were taken from the GenBank database. The population of juveniles S. lewini of the estuarine complex in Sergipe has a high genetic diversity. The high genetic segregation among juveniles is consistent with the adult females pattern of philopatry already known for the species. The sharing of haplotypes between juveniles of Sergipe and adults from regions far away within Atlantic suggests a connectivity, at least historical, for the species.