Estrutura genética populacional de Brycon hilarii (Characidae) da sub-bacia do Rio Miranda, e seu significado para programas de conservação
Resumo
Brycon hilarii (subfamily Bryconinae, Characidae), popularly known as
piraputanga, is a migratory fish species distributed throughout the
entire Paraguay River basin and largely appreciated for its meat quality
as well as for fishing, besides being the main species of touristic value
in the Bonito region (MS, Brazil). Considering the lack of information on
the population genetic structure of these fish, the objective of the
present study was to analyze, through the use of microsatellite
markers, the distribution of the genetic variability in Brycon hilarii
collected in different localities of the Miranda River sub-basin (Paraguay
basin) in the Bonito region (MS). For such an end, at first a total of
seven polymorphic microsatellite loci capable of producing a
considerable genetic variation was prospected (among di-, tri- and
tetranucleotides), with their also being efficient in the heterologous
amplification for five other species of the genus. In the populational
analysis of B. hilarii, the different samples presented very similar
genetic diversity levels. Through the FST values, gene and genotype
differentiation tests and Bayesian analysis, it was possible to verify (1)
the existence of at least two genetic populations of Brycon hularii
coexisting in the sampled range, despite being a potentially mobile
species; and (2) that only the fish from a reproductive stock were
genetically differentiated from the other samples, representing a
putative population unit. It is possible that in the reproductive season
the more genetically homogeneous individuals organize themselves into
a population genetic unit or a reproductive stock, aiming the
maintenance of their genetic integrity. These results on the genetic
structure of B. hilarii constitute tools of extreme importance considering
they can aid the understanding of the behavior and biology of these
fish, contributing to fish management and species conservation
programs.