Traditional sperm whale identification has long relied on photographing tail flukes from boats, capturing the distinctive notches and patterns that make each whale unique. However this method has a significant limitation: researchers can only identify whales when they perform their characteristic deep dive, raising their tails above the surface. Now, drone technology is opening new possibilities for studying these remarkable marine mammals.
A new study spanning the eastern North Atlantic demonstrated how aerial imagery is revolutionizing whale research. Flying at heights of around 25 meters, consumer-grade drones captured detailed images of sperm whales’ entire dorsal surface, revealing identifying features that were previously difficult or impossible to document from boats (with handheld cameras).
Building a large catalog from above
Over seven years of fieldwork (2017 to 2024) in Norway, the Azores, Scotland, and Ireland, researchers documented 336 individual whales using this aerial approach. The overhead perspective revealed a range of identifying characteristics: permanent scars, skin patterns, white patches, and distinctive markings that persist over multiple years. These features are particularly valuable for identifying younger whales and mother-calf pairs since they rarely display their flukes when diving.
Beyond just identification, drone photography is changing how whale research is conducted. The technology allows scientists to simultaneously observe multiple widely spaced animals and monitor surface behavior patterns that weren’t easily visible from boat-level perspectives. The method is particularly valuable during focused research activities like biopsy sampling or satellite tagging, where comprehensive identification of individuals is crucial.
Stories written on sperm whales’ skin
The aerial views also provide unprecedented insights into the whales’ past and health. Permanent scars tell stories of past encounters – thin lines from fishing gear entanglements, deep indentations from ship strikes, and rake marks from social interactions with other whales. During the study, these permanent markings proved reliable for identifying individuals over periods of up to three years.
Other markings are more ephemeral but no less informative. White whale lice cluster on females and young whales, providing temporary identification markers and potential clues about the animals’ health. Skin lesions and blotches vary with water temperature, appearing more frequently in warmer waters (19-26°C) than in cooler regions (14-18°C). While these temporary marks may not serve for long-term identification, they still offered valuable insights into sperm whale health.
The future of drones in whale research
The implications extend beyond sperm whales. Researchers are already applying similar techniques to other marine mammals, from belugas to dolphins. Combined with emerging technologies like artificial intelligence for image analysis, drone photography promises to enhance our understanding of marine mammal populations worldwide.
However, the approach isn’t without challenges. Careful protocols are necessary to avoid disturbing the whales, and environmental conditions like wind and precipitation can limit drone operations. Remarkably, sperm whales from this study showed little reaction to drones unless the aircraft flew unusually close (within 5-25 meters). When they did react, they typically rolled to one side, possibly attempting to view the drone. This tolerance suggests that well-planned drone operations can gather valuable data while respecting the animals’ space.
As ocean ecosystems face growing pressures from climate change and human activities, such innovations in research methodology are increasingly valuable. The ability to track and identify individual whales more effectively, particularly younger animals and social groups, will provide crucial data for conservation efforts.
Sources and further reading:
- O’Callaghan, S. A., Al Abbar, F., Costa, H., Prieto, R., Gammell, M., & O’Brien, J. (2024). Aerial Photo-Identification of Sperm Whales (Physeter macrocephalus). Aquatic Mammals, 50(6), 479-494.
- Degollada, E., Amigó, N., O’Callaghan, S. A., Varola, M., Ruggero, K., & Tort, B. (2023). A novel technique for photo-identification of the fin whale, Balaenoptera physalus, as determined by drone aerial images. Drones, 7(3), 220.
- Ryan, K. P., Ferguson, S. H., Koski, W. R., Young, B. G., Roth, J. D., & Watt, C. A. (2022). Use of drones for the creation and development of a photographic identification catalogue for an endangered whale population. Arctic Science, 8(4), 1191-1201.
- Raudino, H. C., Cleguer, C., Hamel, M. A., Swaine, M., & Waples, K. A. (2022). Species identification of morphologically similar tropical dolphins and estimating group size using aerial imagery in coastal waters. Mammalian Biology, 102(3), 829-839.
Did you enjoy this post about sperm whales? Consider checking our other posts about sperm whales and how scientists can measure their size using sounds:
Anaïs is the founder of Whale Scientists. She is a postdoc fellow at Simon Fraser University working on killer whale ecology, pollution, and health impacts. You can read more about her here.
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