The present study investigated energy allocation patterns in three fish species from the family Hemiodontidae (Argonectes robertsi, Hemiodus microlepis, and Hemiodus unimaculatus), before and after the construction of Lajeado Dam, Tocantins River, Amazon basin. Changes in the use of energy (between somatic and reproductive processes) were indirectly evaluated by means of temporal variations in fish body condition, feeding activity, visceral fat storage, and reproductive effort. Fish were collected from October 1999 to September 2004, in periods that preceded and followed the construction of the dam. We recorded significant changes in all ecological traits for the three analyzed species (for males and females). In general, there was an intense reduction in... |