Tracking whale sharks to protect their habitat in Madagascar
Marokintana or ‘many stars’, as the Malagasy call whale sharks, roam Madagascar’s waters following cues from the seasons. Stella’s tracking research has found that whale sharks appear to be using Nosy Be’s waters more than initially imagined. She now wants to know if juvenile whale sharks are using the area year-round. Acoustic data from tracking have helped delineate a Key Biodiversity Area and an Important Shark and Ray Area. Stella hopes that whale shark habitat, identified through acoustic data, will continue to be the focus of protection efforts, such as the establishment of a new marine protected area corridor, Tandavandriva.
Stella Diamant
Born in Belgium, I was always drawn to the natural world, remote places and exploration. I am fascinated by marine megafauna and their mysteries and strive to use my scientific knowledge to support sustainable development and capacity building at my study site. After studying biology at the University of Warwick, I visited Madagascar for the first time and knew I would return. The island has amazing wildlife and biodiversity, but very little is known about the life in its waters, even though this life plays such a major role for communities locally.
After specialising in ecology and...
Madagascar Whale Shark Project
Our primary objective is to identify whale shark habitat in order to better protect the species. We know that juvenile whale sharks use the region seasonally but, in a bid to support ongoing regional efforts for the enhanced protection of sharks and rays in Madagascar, we are investigating whether they use the area year-round.
Whale sharks are present in Madagascan waters, but their numbers in the Mozambique Channel have been declining in recent decades. They are only visible at the surface at certain times of the year, but acoustic tracking indicates that they appear to be using Nosy Be’s waters more than we initially thought.
Although Madagascar is one of the poorest countries in the world, it boasts unrivalled biodiversity, with up to 90% of its species found nowhere else on earth. In Malagasy, the whale shark is known as marokintana, meaning ‘many stars’. Listed as Endangered by the IUCN since 2016, this largest fish in the world roams Madagascar’s waters following seasonal cues.
Since the inception of the project in 2016, we have identified the bay of Nosy Be as a global hotspot for whale sharks. However, regional marine protected areas, located to the north and south of Nosy Be, do not cover this hotspot. Since 2022 we have been developing a passive acoustic array in north-western Madagascar and deploying tags on whale sharks to monitor their long-term habitat use in this area.
Stored in underwater receivers, the acoustic data are retrieved twice a year and used to further support conservation initiatives locally. For instance, the creation of both a Key Biodiversity Area (KBA) and an Important Shark and Ray Area (ISRA) were made possible thanks to acoustic data. This work is directly supporting the establishment of a marine protected area corridor, Tandavandriva, which will encompass most of the whale shark habitat.
The data we have collected have enabled us to collaborate with a range of partners on the legal implementation of protection initiatives for marine megafauna; code of conduct awareness campaigns; and the development and analysis of research both locally in Madagascar and internationally.
- To continue collecting data to guide the implementation of protection measures, while contributing to global research on whale sharks.
- To expand research themes to include ecotoxicology, population genetics, eDNA and stable isotopes, among others.
- To continue offering training and opportunities to young researchers with the aim of supporting the next generation of Malagasy scientists. After welcoming four Master’s students, we grant one internship opportunity per year to a Malagasy student.
- To support these students as they pursue their academic careers, particularly PhDs in collaboration with partner universities abroad.