Drones have become an important research tool for studies of cetaceans and a popular among many dive travellers who are keen photographers. However, drones can also be a disturbance to cetaceans, particularly when flown at low altitudes.
Drone footage of marine mammals helps us better understand their behaviour and social structure or simply provides us with some stunning footage we couldn't obtain otherwise. However, drones can also affect whales, dolphins and other mammals if flown too close.
So what is too close and what are safe distances?
While using drones to conduct research on the behaviour of beluga whales (Delphinapterus leucas) in the St. Lawrence Estuary, Jaclyn A. Aubin, a PhD student at the University of Windsor, soon noticed that the drones they flew sometimes seemed to disturb the belugas.
Her colleagues also observed sudden dives, where most of the animals below the drone suddenly dove, often with considerable splashing. These responses appeared to be particularly common when the drone was flown at low altitudes, around 20 metres above the water.
Further research into these observations was conducted which examined the impact of drones on endangered St Lawrence belugas and reviewed drone studies of cetaceans to identify altitude thresholds linked to disturbance.
Not closer than 25m
It is recommended that an altitude of minimum 25 m is maintained during drone-assisted studies of belugas and larger groups should be approached with caution. The findings are in line with the literature review, which indicates that drone flights above 30 m are unlikely to provoke disturbance among cetaceans.
Small drones (less than five kilogrammes) were also found to be much more discrete than the large, over 10-kilogramme drone models that are frequently used in modern research programmes.
The findings prompted researchers to make seven recommendations for future drone studies of whales and dolphins:
- Drone studies should maintain an altitude of 25 metres or more.
- Researchers using drones to study whales and dolphins should weigh the conservation benefit of low-altitude flights against the potential for disturbance.
- Pilots should use special caution when flying over large groups.
- Pilots should use special caution when first approaching a group.
- Pilots using large drones (those weighing more than 10 kilogrammes) should be particularly vigilant to drone disturbance and should report on the effects of large drones on whales and dolphins.
- Future drone studies should clearly define the disturbance behaviours they will watch for.
- Using a precautionary approach, drone pilots should avoid sudden accelerations, avoid approaching animals head-on and maintain special caution in low wind conditions.
By reducing the disturbance impact of research on whales and dolphins, we can help protect these amazing animals.