JAMESTOWN, St. Helena (AP) — 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. 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. “To this day we haven’t seen successful copulation, but it is proof (whale sharks) are in our waters trying out these behaviors.”
Whale sharks typically measure from 12 to 18 meters (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.”
Simon Pierce, who has studied whale sharks globally, said he has photographed suspected mating scars on female sharks in St. Helena, probably from when male sharks bit their pectoral fins to hold onto them and get into mating position.