Use of Unnamed Aerial Vehicles (UAVs) to monitor marine megafauna strandings in beach monitoring programs

Strandings of marine mammals, seabirds, and marine turtles in coastal areas can provide valuable information on their ecology. However, gathering information by field teams often incur high costs and effort. This study evaluated the effectiveness of an Unmanned Aerial Vehicle (UAV) to detect stranded animals during beach monitoring programs. The study was carried out between 2016 and 2017 evaluating factors related to the UAV (height and camera angle) and the beach (morphology). Data obtained from the UAV was compared with the traditional method of in situ teams. A total of 120 aerial surveys were conducted on four beaches on the coast of Santa Catarina, Brazil. Eighteen carcasses were recorded by both methods, traditional methodology and UAV. However, six other events were only recorded by in situ monitoring (traditional method) and one event recorded only by the UAV. The time interval between the beach monitoring by the two strategies is probably responsible for the differences. Despite obtaining high-quality aerial images and easily identifying strandings, the UAV cannot completely replace the traditional method due mainly to the impossibility to fly in adverse weather conditions such as high winds and rain. On the other hand, UAVs can complement the data collection information, with less consumption of fossil fuels and damage to the coastal environment.