Mitigation and Conservation Actions for Fish Management in Tropical Rivers of Brazil Impacted by Hydropower Plants

In Brazil, hydropower is considered a major threat for several fishes. Therefore, hydropower managers are required to develop studies and strategies in order to alleviate the impact of dams on fish. However, the great diversity and life-histories, especially of migratory and reophilic species, make management a hard task. Monitoring and fish stocking programs are the oldest actions recorded for reservoirs and several evidences have shown that they were not satisfactory. In the last two decades, fish passages have emerged as a management tool for fish conservation, although the success of a fishway to achieve this goal has been very controversial. Moreover, the costs to develop a fish passage at a dam is quite high whilst its benefits have been quite low. These mitigation actions can only be directed to the fish fauna that will remain in the reservoir. Conservation actions for the migratory species in tropical environments require a more holistic overview of a catchment, as well as basic studies to identify critical habitats based on the life-history of target species. This study will discuss the applicability of this approach to other tropical systems, like the Mekong River, considering their similarities for the fish fauna.