As many as 85 whale sharks have been spotted off the coast of Madagascar, as reported in the first major scientific survey of the area.

This promises to be a boost for eco-tourism for the island, as tourists travel to see and swim with the gigantic, harmless sharks. They are called marokintana by the locals, meaning ‘many stars’ because of their unique spotted patterns.

The data suggests that the sharks – all juveniles – had not migrated from Mozambique or other neighbouring areas. However, satellite tags attached to the sharks to track their movements showed that half of them visited a second hotspot off southern Madagascar, and five of them swam over to Mayotte and the Comoros islands.

"Madagascar clearly provides an important seasonal habitat for these young whale sharks, so we need to ensure they are effectively protected in the country," said Stella Diamant of the Madagascar Whale Shark Project in Nosy Be, an island off the coast of Madagascar. Protection of the species is important, as the whale shark (Rhincodon typus) – the world's largest fish – is classed as globally endangered on the RIUCN RedList. Overfishing, accidental catches and boat strikes are named as causes for the dramatic decline of the species – which has seen more than 50% decline over the past 75 years.

Madagascar is known for its huge diversity of marine life, including sharks, whales and turtles, and Simon Pierce, Principal Scientist at the Marine Megafauna Foundation, says: “These sharks can be a major asset for the country. There's already a good marine ecotourism industry developing.”