Adopt a Whale Shark

Why adopt a whale shark?

Whale sharks are the biggest fish in the world, and they are harmless to people. These filter feeders eat some of the ocean's smallest animals, and their tiny teeth play no part in feeding. When you adopt a whale shark, you back the people working to keep them in the sea.

They need that help. The current IUCN Red List assessment, led by MMF scientists, keeps whale sharks Endangered and still declining. It infers that numbers have fallen by 50 to 79% over the past three generations, about 120 years. Decades of targeted fishing did most of the damage.

Today the biggest problems are whale sharks caught accidentally in fishing nets and whale sharks killed by ships. A satellite-tracking study we contributed to found that 92% of the tracked sharks' horizontal space use overlapped with persistent traffic from large vessels. A dead whale shark typically sinks rather than washing ashore, so many of these deaths likely go unrecorded.

About whale sharks

The largest widely accepted length estimate for a whale shark is 18.8 meters (62 feet), and one reported catch weighed 34 metric tons (37 US tons). The second-largest fish, the basking shark, reaches about 12.3 meters (40 feet). Whale shark skin is up to 15 cm (6 inches) thick, the thickest in the animal kingdom.

For all that size, whale sharks feed on shrimp, fish eggs, krill, copepods, and crab larvae, plus small fish such as anchovies. Their prey must be small, because a whale shark's throat is only about the size of a baseball.

Whale sharks live in all tropical and warm temperate oceans, with their core range between about 30°N and 30°S. More than 50 coastal sites with predictable gatherings are now known, and young males of 4 to 8 meters (13 to 26 feet) dominate most of them. They also travel far: two sharks tagged off Madagascar by the Madagascar Whale Shark Project traveled at least 3,414 and 4,275 km (2,120 and 2,660 miles).

Each whale shark's spot pattern is unique and stable over decades, so a clear photo can identify the same shark year after year. Much of their life is still a mystery. Scientists have examined only one pregnant whale shark, which was carrying about 300 embryos.

How your whale shark adoption helps

Your whale shark adoption supports MMF's work as a whole, including the Global Whale Shark Program, led by MMF's Dr. Simon Pierce, who co-edited the first scientific textbook on whale sharks and led the species' current Red List assessment.

Through the program, we lead or contribute to research at whale shark aggregation sites:

• Mozambique: we have studied the sharks of southern Mozambique since 2005. Our 15-year survey off Praia do Tofo recorded an 87% drop in sightings, and our research and lobbying were a major factor in their legal protection in January 2021.
• Tanzania: at Mafia Island we have monitored the same sharks since 2012 and identified 268 individuals, and monitoring from 2012 to 2019 found a stable population with high survival, a rare finding for this Endangered species.
• Oman: our first dedicated field season, in June 2025, photo-identified 30 sharks and deployed nine satellite tags, the first ever placed on whale sharks in Omani waters.
• Galápagos: the Galapagos Whale Shark Project leads the research at Darwin Island, one of the very few places where large females can be found predictably, with MMF as a collaborating partner. There, the team made the first ultrasound scans of wild whale sharks.
• Madagascar: the Madagascar Whale Shark Project leads research at Nosy Be, with MMF collaborating. There, 546 sharks had been identified by the end of the 2025 season and the tourism code of conduct is now Malagasy law.