Different stocks of Prochilodus lineatus along the Cinzas River basin: contributions from a free-flowing tributary in the Capivara Reservoir region, Paranapanema River basin (upper Paran River)

Dams are one of the main threats to Neotropical potamodromous fish, causing blockages of migratory routes and loss of breeding areas in an increasing number of drainage systems. In this scenario, current data argue that the maintenance of free-flowing tributaries along fragmented watersheds would be an important strategy to the migratory fish conservation, both in panmixia situations and in scenarios with different coexisting stocks, as already reported for Prochilodus lineatus. This study analyzed microsatellite loci and mitochondrial haplotypes in samples of P. lineatus obtained in different years along the Cinzas River basin, as well as in the Capivara Reservoir (largest Reservoir in the Paranapanema main channel, upper Parana River) and in the Tibagi River, all connected by free stretches, aiming to investigate the contributions of the Cinzas River basin to the population dynamics of migratory fish in the Capivara reservoir region. Both markers detected high genetic diversity levels and indicated different genetic stocks of P. lineatus along the Cinzas River basin, suggesting some temporal genetic structuring, as well as the mixture of these stocks in the sample from the Capivara reservoir and from other points, corroborating the relationships among stocks in this reservoir and its tributaries.