Indeed, "shark-infested" is journalistic cocaine used to excite readers.
Unless one jumps into the middle of a shark-frenzy with an already bloody carcas in the middle, sharks are cautious creatures that will first circle prey, take some time to figure out what it is, confirm if its edible, make an exploratory bump/bite (which nonetheless could be fatal to humans) etc...
I don’t remember who it was who said the waters are so shark infested, to this day, because so many slaves were thrown overboard. Rush use to play the clip on his show. It was from his TV show days.