Marine mammals have long been considered sentinels of the sea, providing crucial insights into the health of ocean ecosystems. When dolphins and whales exhibit signs of stress or illness, it often signals underlying issues within the marine environment that humanity relies on. However, assessing the health of these creatures poses significant challenges due to their aquatic lifestyle, extensive migratory patterns, and the stress caused by close examination.
In a groundbreaking study published in the Journal of Thermal Biology, researchers have unveiled a promising solution: drone-mounted thermal cameras capable of monitoring dolphins’ vital signs, such as skin temperature and breathing patterns, without physical contact. This innovative approach could revolutionize how scientists study marine mammals, offering a non-invasive alternative to traditional methods.
Monitoring Animals Without Handling Them
Historically, scientists have relied on invasive techniques to assess the health of wild marine mammals. These methods often involve attaching tagging devices or taking measurements during capture and handling, which can be costly, complex, and stressful for the animals. Such stress can alter their behavior and physiology, complicating the interpretation of results.
To address these challenges, researchers have been seeking tools that enable repeated and accurate monitoring of dolphins with minimal disturbance. Enter drones equipped with thermal cameras, which detect heat emitted from surfaces, allowing remote measurement of temperature patterns. When mounted on drones, these cameras can potentially gather data from above, enabling animals to move freely without interference.
For dolphins, this technology promises to measure skin temperature and breathing patterns based on the heat emitted from their blowholes, bodies, and dorsal fins, all without the need for close proximity or physical contact. Until now, the practicality and accuracy of this approach in real-world conditions had not been thoroughly tested.
Testing Drones on Dolphins
In the study, researchers employed a drone-mounted thermal camera to measure the body surface temperature and breathing rate of dolphins under controlled conditions that mimic wild monitoring scenarios. The study involved 14 adult common bottlenose dolphins at Dolphin Beach, Sea World on the Gold Coast, Australia. Various heights, camera angles, and environmental conditions were tested to validate drone-based measurements.
Measurements obtained from drones were compared with close-range reference data collected simultaneously. Body surface temperature was assessed using hand-held thermal cameras, while breathing rates were calculated from the drone’s visual footage. This comparison allowed researchers to evaluate the accuracy and reliability of drone measurements.
Notably, the study required no restraint or tagging, as drone-based measurements were collected without physically handling the animals. The findings revealed that the manner in which the drone was flown significantly impacted measurement accuracy. For instance, flight height influenced the reliability of body surface temperature and breathing rate estimates.
Measurements collected at lower altitudes, particularly around ten meters directly above the dolphin, consistently produced the most accurate results. At this height, body surface temperatures derived from thermal imagery closely matched close-range reference measurements taken at the same time.
As flight height increased, measurement accuracy declined, though temperature estimates remained within approximately 1°C of the reference measurements. Camera angle also played a role, with thermal measurements proving most accurate when the camera was positioned directly above the dolphin. Breathing rates were accurately estimated from thermal imagery, as each breath produced a brief, localized temperature increase at the blowhole visible in the footage.
Growing the Conservation Toolbox
The results demonstrate that drone-mounted thermal cameras can reliably measure dolphins’ surface temperature and breathing rate, marking a significant advancement in monitoring dolphin vital signs in the wild. Previously, repeated temperature and breathing measurements required researchers to be in close proximity to dolphins, either from boats or by capturing and handling the animals.
This limitation restricted the frequency of measurements. Thermal drones offer a solution, enabling routine data collection without significantly disturbing dolphins. This approach could enhance our ability to detect physiological changes and examine how dolphin health varies over time in the wild. When combined with behavioral observations, drone-based thermal imaging could help explore links between surface temperatures, breathing patterns, and environmental conditions.
While the study focused on dolphins under human care, the same approach could be applied to free-ranging dolphins and other marine mammals for which close-range monitoring of vital signs is challenging. As coastal ecosystems face increasing pressure, tools like thermal drones that allow researchers to monitor wildlife efficiently, repeatedly, and non-invasively will become increasingly important. They provide a practical addition to the conservation toolbox, aiding in the understanding and protection of dolphins and other marine animals in a changing ocean.
The authors acknowledge the contribution of Dr. Andrew Colefax to this research and the support and in-kind contributions from the Sea World, Gold Coast team.
/Courtesy of The Conversation. This material from the originating organization/author(s) might be of the point-in-time nature, and edited for clarity, style, and length. Mirage.News does not take institutional positions or sides, and all views, positions, and conclusions expressed herein are solely those of the author(s).
