Nobody knows where whale sharks, the biggest fish in the sea, are mating. But scientists suspect it 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. St. Helena is the only place in the world where adult male and female sharks are known to regularly gather in roughly equal numbers, and food doesn’t seem to be the main attraction. In recent years, scientists have gathered some highly suggestive photographic and video evidence pointing to a possible mating grounds.