The shortage of baitfish due to overpopulation forces them to seek other food.
Over here (Puerto Rico/Caribbean) shark attacks have numbered like nine over the last hundred years. Why? Overfishing. Shark fins are great for sheshkabobs (sp?). Teeth or full jaws make great souveneirs. Shark oil is good for a number of things. The rest have to be tossed out. Take notice, Florida.
Before a tree-hugger zots me, sharks are mostly scavengers of injured or dead seafood.