Estruturação genética populacional de Salminus hilarii (Characiformes : Characidae) na Bacia do Alto Paraná
Abstract
The Salminus genus is characterized by predatory fish medium to large, migratory and
ichthyophagi, very appreciated in fisheries and gastronomy. Among these stands out the
Salminus hilarii species, popularly known as tabarana and considered top of the food
chain, due to its high degree of selectivity for environments with rich water oxygen which
constitutes a good environmental indicator. This species occurs in the São Francisco
basins, Paraná basins and Jaguaribe river, and depends on specific hydrological conditions
to carry out their reproduction. In this context and because of intense anthropogenic
interference that such river systems have suffered, population's study of tabaranas in the
upper Paraná basin can contribute to a better understanding of aspects related to its
population structure and conservation of their populations. Thus, the aim of this study was
to characterize the population genetic structure of S. hilarii at different periods in rivers of
the Upper Paraná basin, in order to better understand the population dynamics of fish and
effectively contribute to their conservation. It was used for molecular analysis 15
polymorphic microsatellite loci and mtDNA (D-loop). The results revealed the existence of
population differentiation among the rivers sampled. Nevertheless, individuals sampled in
the Jacaré-pepira river and Cubatão showed no genetic difference, indicating the
occurrence of gene flow between populations sufficient to maintain the genetic
homogeneity. Moreover, it was possible to identify the temporal structure into the Turvo
and Jacaré-pepira river. A high genetic diversity was found in populations of Upper Paraná
basin sampled rivers. The D-loop analysis showed no population structure between
samples, but indicated the occurrence of a high diversity. The contradictory results may be
due to mutational rates of the markers used, since microsatellites have high mutational rate.
These results are important for understanding the behavior and biology of these fish, and
also to establish fisheries management programs and conservation S. hilarii in the upper
Paraná basin.