Acoustic landscape downstream of hydroelectric dams: The case of Luis Eduardo Magalhães power plant Free

The increasing demand for electric power has resulted in government action to expand the energy sector. In Brazil, approximately 68.1% of electricity is produced by hydroelectric plants. In this scenario, the ichthyofauna suffers significant anthropogenic interference. This is the result of migratory routes and access to spawning areas being interrupted and mortality downstream of the dams as fish pass through the turbines and spillway or get caught in the suction pipe when turbines are halted for maintenance. We sought to understand how the underwater acoustic landscape changes according to the operating activities of the Lajeado Dam (Luis Eduardo Magalhães hydroelectric power plant) located on the Tocantins River and how this affects the behavior of ichthyofauna. We monitored the acoustic landscape using a hydrophone; the underwater recordings were obtained downstream from the dam in a calm water location near the entrance of the fish ladder. The spectrograms and sound pressure level (SPL) were characterized by the contents of the recordings. Different protocols were used, including experiments with the fish ladder opening and varying the downstream level to verify the occurrence of the changes in the SPL.