Características reprodutivas relacionadas ao sucesso na colonização de espécies do gênero Astyanax em Reservatórios da bacia do rio Iguaçu-PR

Abstract

The reproductive responses of Astyanax species were evaluate in the initial colonization of thirteen reservoirs from Iguaçu River basin. Oocytes number and diameter, besides the gonadosomatic index were utilized as indicators of reproductive strategy. These variables were arbitrarily divided in three classes, according to obtained values: smaller, intermediate, and bigger. One-way ANOVA analysis revealed significant differences between species abundance and oocytes diameter and RGS. Inversely, significant differences were not observed for fecundity. In general, species with intermediate oocytes size, low fecundities and high values of RGS (reproductive strategies of Astyanax sp. B) were the most abundant ones. These results differed, partially, of a expected pattern (small oocytes and high fecundity), probably due to the predominance of Astyanax sp. B in captures.