Eletrosensibilidade em peixes: fundamentos para o desenvolvimento de uma alternativa para repulsão de peixes no tubo de sucção de turbinas de Usinas Hidrelétricas

Abstract

The impoundments have considerable impacts on populations of native fish species, particularly migratory species. One of the major causes of impacts on ichthyofauna are routine operating procedures downstream of the dam of hydroelectric power plants, when the flow of water through the turbines is reduced, and then significant amount of fish advances the tailrace entering the pipe where they can be seriously injured by clashes with the components of the turbine or due to low concentrations of oxygen. The use of repulsion and targeting fish systems is an alternative to minimize the impacts of dams on fish populations. Among these systems, behavioral barriers are very promising strategies, as they are built in order to change the behavior of certain species, causing them to avoid risk areas. Therefore strobe light, infrasound, bubble curtains and electric field are used. Thus, since the fish are sensitive to electric fields, this study aimed to evaluate the electrobehavioral responses in adult Prochilodus lineatus, Brycon cephalus and Leporinus macrocephalus in order to get to know the electrosensitivity levels of each species and possible differences in these levels within the species and between species. The results of electrosensitivity tests were evaluated through an ANCOVA test, where it was observed that there was no significant relationship between the lengths and weights of the tested individuals and their electrosensitivities, and curimba was more sensitive to electric fields and was significantly unlike matrinxã and piauçu to the sensitivity, agitation and paralysis thresholds. In spite of the fact that the recovery times do not show statistical differences between species, piauçu showed itself more tolerant to electric currents, as it had the lowest recovery times between species. Such results were fundamental to the understanding of fish reactions involving the application of electric fields and for future projects on the construction of electrical behavioral barriers.