Variabilidade genética em espécies de Rhamdia (Siluriforme, heptapteridae) utilizadas para repovoamento de rios no Estado do Paraná

Abstract

The cultivation of Rhamdia spp, also known as jundiá, it has increased in south of Brazil, because its induced reproduction shows good results and high fecundation rates in repopulation programs. The genetic monitoring of stocks involved in these projects is essential to minimize the genetic changes that may occur as a result of inbreeding, genetic drift and adaptation to cultivation conditions. This study aimed to evaluate the genetic variability in species of Rhamdia spp used in stocking programs of rivers in the state of Paraná through isoenzymatic markers. It was collected 30 individuals of each species, R. branneri, Rhamdia quelen, and R. voulezi in two tanks of fish culture in the state of Paraná. The electrophoresis analysis of 11 systems, among the three species analyzed, it was detected 19 loci, with 60% of polymorphic loci. The values of heterozygosity observed and expected were much above average for fish (0.05). The value of Sewall Wright's FIS showed that in the average of the three species there is an excess of homozygotes in relation to the expected by the Hardy-Weinberg equilibrium. The data suggest that although the species are reproducing in captivity, they still have a high genetic variability.