I find it funny that people seem to forget the largest predator of all time currently roams the ocean...but no one worries about getting eaten by a Sperm Whale when at the beach. A fish the size of Megalodon wouldn't even bother with small fry like people, they preyed on whales.
lol, but hey, there are still freshwater spots in asia and china that haven't ever been explored thoroughly. They could still be lurking around in isolated areas. =D