Whale watching in the 21st century
Drones are making waves in marine conservation
SOUTH AFRICA: Changing the face of marine conservation research, specialised drone technology and processes are being used to observe and assess Southern Right Whales in a cost-effective, non-invasive manner that will help to protect this species and assess the impacts of a changing climate on sensitive marine ecosystem.
The Endangered Wildlife Trust (EWT) has partnered with the University of Pretoria’s Mammal Research Institute (MRI) Whale Unit to enable critical research on the body conditions and behaviour patterns of Southern Right Whales (Eubalaena australis) using drone technology.
The body condition and calving rates of these majestic animals are important factors when assessing the potential threat of global warming to the Southern Right Whale population. Their main food source is krill (a small shrimplike planktonic crustacean), and current research indicates that changes in ocean temperatures affect the abundance and location of these and other creatures, with far-reaching environmental consequences.
Dr Els Vemeulen, Research Manager of the MRI Whale Unit, said: “Drone technology has revolutionised the way we conduct our research. Using drones, we can gather overhead images of right whales every year, allowing us to track the variation in their body condition over time in a very cost-effective manner, and collect additional photo-identification data, which allows us to assess the residency time of individual animals on the South African breeding ground. Also, an aerial view of these animals reveals more information on their behaviour than viewing them from a boat. It is truly a unique piece of technology that can be adjusted for various research projects, and we aim to apply it in much more of our research going forward.”
In this study, the Whale Unit uses photographs to assess the temporal change in the body condition of South Africa’s Southern Right Whales. These images are a mixture of aerial photographs collected in South Africa in 1988 and 1989 using a helicopter and, more recently, photographs collected using a drone. Drone images from South Africa are also applied in a comparative study with images of Southern Right Whales captured in Australia and Argentina.
After data filtering, the selected images are used for photogrammetry purposes. Using a custom-written script, measurements of the total body length and width are made (in pixels) at 5% increments perpendicular to the body axis for each whale. Subsequently, using the altitude data from the drone, these measurements in pixels can be converted to true measurements in meters. Researchers can now calculate the Body Condition Index (BCI) using the established height-width ratio of a Southern Right Whale. A positive BCI means that an animal is in better condition than the average of the sample population and a negative BCI indicate that the animal is in poorer than average condition. Clear images of the head are also used to identify animals, enabling the long-term tracking of several individual whales.
Lourens Leeuwner of the EWT Drone project said: “We are really excited to assist the Whale Unit with this important work by providing a licensed drone pilot, ensuring all work can be conducted in accordance with permit conditions. This research is a perfect example of why the EWT started the Drone project: to support conservation work across the country through affordable aerial solutions.”