Using Drones And Rov To Assess The Vulnerability Of Marine Megafauna To The Fundao Tailings Dam Collapse

The ecology and life history of marine megafauna can answer the ecological importance of a region. This study assesses and monitors the abundance and home range of sea turtles, seabirds, marine mammals and the association with coastal miaohabitats in potentially impacted areas at the Rio Doce river mouth, Comboios, and Piraque-acu river mouth after the collapse of the Fundao dam. Remotely Operated Vehicles (ROV) and UAVs (Unmanned Aerial Vehicles, or drones) were used for megafauna species identification, behavior, population data, habitat characterization, and monitoring of environmental protection areas. The species Sotalia guianensis and Pontoporia blainvillei were the most recorded cetaceans, and the main observed behavior was feeding. Guiana dolphin (S. guianensis) occurs in greater density in the Rio Doce river mouth region, resulting in more than 10 sightings/km(2), while franciscana (P. blainvillei) were the most concentrated Comboios area. The seabirds (all species) had up to 15 sightings/km(2) at the Rio Doce river mouth, the highest density among sampled areas. The green turtle (Chelonia mydas) was the most frequently recorded, followed by the leatherback turtle (Dermochelys coriacea). The green turtle occurred at a higher concentration at the Piraque-Acu river mouth (above 6 sightings/km(2)). The sites dosest to Rio Doce river mouth and Comboios predominantly showed mud bottoms, while those at Piraque-Adi mouth were mostly reef structures. The estuarine areas showed greater importance for megafauna than marine areas. (C) 2021 Elsevier B.V. All rights reserved.