Scientific data collection

Science as a tool for conservation

The Madagascar Whale Shark Project’s main scientific objective is to establish the occurrence, residency, and population structure of whale sharks off Nosy Be, Madagascar.

This is achieved through the collection of standardised sighting data, such as the GPS location, size and gender of all individuals, coupled with photo-identification for every encountered shark. Data is collected while free diving from the boats of Les Baleines Rand’eau, our local operating partner. When possible, we also collect small skin samples to examine diet and movements using biochemical markers (stable isotopes and fatty acids), along with population genetics and genomics studies, collaborating with multiple scientific institutions.

Whale shark photo-identification data is compared with photos collected throughout the Indian Ocean, and further afield, using a global online database of whale shark sightings ( This enables us to investigate the connectivity of Madagascar to other regional aggregations through the movements of individual sharks. So far, we have identified more than 400 individual juvenile whale sharks; yet, none of these individuals have been spotted elsewhere. We also deployed satellite tags on whale sharks in 2016 in order to better understand their movements; activity which resulted in the publication below.

Finally, we provide information necessary for appropriate management measures in Madagascar and in the Western Indian Ocean through publications and data sharing.

Identified whale sharks since 2015

The objectives of the project are to investigate:

Population size and structure
Thanks to dedicated photo-identification efforts we can infer population size and structure. Because each whale shark bears a unique spot pattern, we can easily tell individuals apart, and also determine the size and sex of each shark.
Movements and residency
Thanks to the combination of satellite tags, photo-identification and genetics we are starting to better understand horizontal movements and residency patterns of the Nosy Be population.
Feeding ecology
Through collaborations with specialized teams and sampling we are trying to better understand the drivers of whale shark presence: the food sources they rely upon.
Socio-economic value
Through interviews with tourists and operators we are quantifying the socio-economic value of live whale sharks as an economic asset to Madagascar’s economy, another argument for protecting their habitat.
Local perceptions
How are whale sharks perceived by local communities? Better understanding the cultural spatio-temporal importance of whale sharks across Madagascar is key to their survival.