This work aimed to determine which population features were important to the colonization process of Astyanax altiparanae in the Corumbá Reservoir. The species presented wide spatial-temporal distribution, caught in all months and sites. Higher CPE values were recorded upstream from the reservoir during the filling phase. In this phase, reproductive activity was intense upstream and moderate in the tributaries. However, a fall in abundance of juveniles was observed after the formation of the reservoir. Among the most relevant population features to grant a successful colonization were wide geographic distribution, ability to occupy and spawn in lentic habitats and feeding flexibility.
Astyanax altiparanae; reservoir; colonization; reproduction
