They're Huge Fish With a Huge Mystery

Where do whale sharks mate? It's not an easy question to answer
By Newser Editors and Wire Services
Posted Apr 19, 2025 10:30 AM CDT
Scientists Try to Get to Bottom of a Whale Shark Mystery
In this image from video, whale sharks swim near each other off the coast of St. Helena in the South Atlantic Ocean on Feb. 25, 2025.   (AP Photo/Maria Cheng)

Whale sharks shouldn't be hard for scientists to find. They are enormous—they are the biggest fish in the sea and perhaps the biggest fish to have ever lived. They are found in warm oceans all around the world. By shark standards, they are slow swimmers. But they somehow manage to also be very private: Scientists don't know where they mate, and they've never observed it before. They do finally have some clues, though, reports the AP.

Scientists suspect the magic may be happening in the waters around St. Helena, a remote volcanic island in the South Atlantic Ocean where Napoleon Bonaparte was once exiled and died. It's the only place in the world where adult male and female whale sharks are known to regularly gather in roughly equal numbers—and food doesn't seem to be the main attraction. Kenickie Andrews, the marine conservation project manager at the St. Helena Trust says he's seen male sharks chasing females, nibbling on their pectoral fins and "displaying themselves" to the female sharks, akin to mating rituals observed in other sharks including great whites. "What we've seen here is classic shark courtship behavior," he said.

Whale sharks typically measure from 39 to 59 feet, weigh up to 14 tons, and are plankton eaters; all sharks have a unique pattern of white spots on their upper side. Scientists say they need to know where the sharks are mating and giving birth so they can protect those areas, possibly by creating marine reserves where threats like fishing are banned. Whale sharks are designated as endangered by the International Union for Conservation of Nature; the group says their population has been "largely depleted."

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Fisheries experts in St. Helena have provided eyewitness accounts of what they said were instances of whale sharks mating, but those sightings were not captured on video and are not considered sufficient proof by scientists. Cameron Perry, a research scientist at the Georgia Aquarium in Atlanta, has been working with colleagues on the island to attach camera tags to investigate what the whale sharks are doing, but have run into some technical difficulties: the sharks dive deeper than 6,561 feet and the tags can't withstand the pressure. "We have some very tantalizing and teasing video," Perry said. "We have two sharks about to make contact, and then our camera falls off." Perry isn't sure what the sharks might be doing far below the surface, but hopes new technology being developed will help answer that question.

(More whale shark stories.)

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