Drones have been widely used in the last decade for a host of wildlife studies. They’ve been particularly helpful to advance our understanding of whales, dolphins, and porpoises, because cetaceans are notoriously difficult to observe in their natural environment. But can drones disturb the animals that we strive to understand?
Our study “Fly with care”, published in Marine Mammal Science, investigated that important question. We analyzed 143 drone flights obtained with a DJI Phantom 4 and Phantom 4 Pro (both used extensively in drone wildlife studies) over 27 days, for 28 beluga herd encounters. The footage had been originally collected to study various aspects of beluga behaviour and ecology. We looked at drone altitude, speed, and approach angle, in addition to group size, composition, and behaviour, and evaluated the reaction of the whales based on a series of defined alert and evasive behaviours.
We also conducted a systematic literature review to examine the impact of drone altitude on cetaceans. Of 72 drone studies of cetaceans published from 1979 to 2022, only 31 studies reported drone disturbance and altitude thresholds. We compared the results of such studies with our own.
Based on both the results of our video analysis, and on our review of the literature on cetacean drone disturbance, our paper lists recommendations that apply the precautionary principle and encourage researchers to minimize the potential for negative impacts when using drones to study cetaceans. The main recommendations are that drone-assisted studies of belugas that involve small drones maintain a lower altitude limit of 25 metres, a threshold below which evasive responses were more likely, both in our study and in the literature, and that large groups should be approached with special caution due to the increased likelihood of reactions.
Please follow local regulations when flying drones recreationally
Under the Canadian federal Marine Mammal Regulations, it is illegal to approach marine mammals with an aerial drone at an altitude below 1000 feet (about 304 metres) within a half nautical mile (about 926 metres). Flight maneuvers, including taking off, landing or altering course or altitude, are also not allowed near them.
Our fieldwork methods were reviewed and approved by the Memorial University Animal Care Committee (Animal Use Protocol: 20190640). Our research, and specifically, the use of research drones in the Saguenay St. Lawrence Marine Park was covered by research permit SAGMP-2018-28703 issued by Parks Canada and QUE-LEP-001-2018 issued by Fisheries and Oceans Canada.
Aubin, J. A., Mikus, M.-A., Michaud, R., Mennill, D., & Vergara, V. (2023). Fly with care: belugas show evasive responses to low altitude drone flights. Marine Mammal Science, 1– 22. https://doi.org/10.1111/mms.12997
Drones have become an important research tool for studies of cetaceans, providing valuable insights into their ecology and behavior. However, drones are also recognized as a potential source of disturbance to cetaceans, particularly when flown at low altitudes. In this study, we examined the impact of drones on endangered St. Lawrence belugas (Delphinapterus leucas), and reviewed drone studies of cetaceans to identify altitude thresholds linked to disturbance. We repurposed drone footage of free-living belugas taken at various altitudes, speeds, and angles-of-approach, and noted the animals’ reactions. Evasive reactions to the drone occurred during 4.3% (22/511) of focal group follows. Belugas were more likely to display sudden dives during low-altitude flights, particularly flights below 23 m. Sudden dives were also more likely to occur in larger groups and were especially common when a drone first approached a group. We recommend that researchers maintain a lower altitude limit of 25 m in drone-assisted studies of belugas and approach larger groups with caution. This recommendation is in line with our literature review, which indicates that drone flights above 30 m are unlikely to provoke disturbance among cetaceans.
Authors and affiliations
Jaclyn A. Aubin and Dan Mennill, Department of Integrative Biology, University of Windsor, ON, Canada
Robert Michaud, Group for Research and Education on Marine Mammals (GREMM), Tadoussac, Québec, Canada
Marie-Ana Mikus and Valeria Vergara, Raincoast Conservation Foundation, Sidney, BC, Canada
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