In 2014, a remarkable encounter with a whale shark sparked a journey of discovery off the coast of Madagascar’s Nosy Be. Little did marine enthusiast and researcher, Stella Diamant, know that this encounter would lead to a groundbreaking initiative in citizen science. Fast forward to today, and the results are nothing short of extraordinary: the identification of over 500 whale sharks in the region, cementing Nosy Be’s status as a significant hub for these magnificent creatures in the Indian Ocean and Africa.
Whale sharks (Rhincodon typus) hold the title of being the largest known extant fish species, capable of reaching lengths of up to 40 feet or more. Despite their enormous size, whale sharks are characterized by their peaceful nature and docile demeanor. They boast striking patterns of white spots and lines against a dark background, which make them easily recognizable and sometimes referred to as “checkerboard sharks.” Unlike many other shark species, these filter-feeding giants primarily feed on plankton, small fish, and other microscopic organisms by swimming with their mouths wide open, filtering vast amounts of water through their gills. Found in warm oceans across the globe, they are one of the most popular sharks tourists come to see.
Nosy Be, nestled in the sparkling waters of the Indian Ocean, is located off the northwest coast of Madagascar. Celebrated for its lush landscapes, fragrant plantations, and its diverse and vibrant marine life, snorkeling and diving enthusiasts come from all over to check out Nosy Be’s coral reefs. Teeming with colorful fish, it’s turned out to be a prime location to encounter the whale sharks that frequent its waters. The journey to cataloging this vast number of whale sharks began in 2015 when Diamant partnered with the local operator, Baleines Rand’eau. Their mission was to collect photos and videos of these gentle giants for photo-identification purposes, ultimately shedding light on the whale shark population in Madagascar. Prior to this, only a dozen whale sharks had been identified between 2005 and 2007, recorded on the collaborative global database.
The breakthrough came in 2015 during a pilot season when the operator, in between guiding and operating boats, noted over 200 encounters. These findings were subsequently presented at the Fourth International Whale Shark Conference in Qatar in 2016, with support from the Marine Megafauna Foundation. From there, the project gained momentum. Diamant continued data collection in 2016, and in the following years, volunteers joined the cause in 2017, 2018, 2019, and 2022. Countless partners, divers, photographers, and operators also lent their invaluable support to this ambitious project.
The remarkable milestone of identifying 503 distinct whale sharks solidifies Nosy Be’s standing as a major whale shark habitat. Diamant is quick to acknowledge the collaborative nature of this achievement, emphasizing that it would not have been possible without the contributions of the diverse group of people who participated in the project. “The amazing thing about photo-identification is that anyone can contribute, without a marine biology degree!” she said. “Just by capturing a photo or video of a whale shark underwater, you can contribute to research and conservation efforts.” This approach isn’t limited to whale sharks alone; many other species, like leopards and humpback whales, have unique patterns that scientists use to identify and track them throughout their lives.
To make the identification process more engaging, all the whale sharks in the database were given names rather than impersonal data codes. This approach not only made it easier to remember each shark but also involved the community in the naming process. Nearly 100 people adopted a whale shark, resulting in a diverse and multicultural database. To celebrate the remarkable achievement of identifying 500 whale sharks, the community was invited to participate in a naming contest on social media. “We gave our community the chance to name the 500th whale shark through a contest on social media. After two weeks of voting, one name came out on top: Dimanjato,” Diamant said. “This suggestion, from Instagram user @rhiawelsh is a meaningful one: Dimanjato‘s name is the Malagasy word for ‘500.’ We could think of no better way to honour the community that has embraced and supported our efforts than giving this whale shark such a meaningful name in Malagasy!”
Reaching the 500-mark was a lengthy process that relied on the dedication of over 80 volunteers since 2017. “We are so thankful to the 80+ volunteers who have volunteered with us since 2017, contributing to our efforts; both spatially by being on different boats at different times, and temporally through the different months and seasons,” Diamant continued. “We are also deeply thankful to our long-lasting partners Baleines Rand’eau, who have accommodated us on their boats since 2016, and to many local operators and visiting photographers who shared usable photos. Teamwork makes the dream work!”
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