Insights into the use of an unmanned aerial vehicle (UAV) to investigate the behavior of humpback whales (Megaptera novaeangliae) in Vava'u,Kingdom of Tonga

Vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs) are becoming invaluable data collection platforms for cetacean research. In particular, multi-rotors can be used to measure whales and investigate their behavior. Moreover, VTOL UAVs are increasingly accessible for recreational and commercial pilots, and close encounters with whales are widely documented. Unfortunately, quantitative assessments of potential disturbance for the targeted animals are not yet published and guidelines for responsible use of UAVs around cetaceans are still under development. We conducted VTOL UAV surveys on humpback whales in Vava'u, Kingdom of Tonga. Interestingly, whale behaviors such as socializing and nurturing were not detected by trained observers on board the research vessel, but were evident from the UAV. Nevertheless, no significant differences were detected in diving and swim parameters between absence and presence of UAV flying at 30 m altitude. These results suggest that VTOL UAVs can be a noninvasive tool to gather morphometric and behavioral data on baleen whales. However, further research is necessary to establish whether applications that require flight altitudes lower than 30 m and targeting different species may elicit behavioral responses.