When sharks are removed from their habitats en masse, as a group of marine biologists argued in a 2007 paper in Science, the negative effects can be wide-ranging. The overfishing of sharks led to increased populations of rays and skates, the ecologists said. And without predatory sharks to keep them in check, large numbers of hungry rays and skates may have contributed the devastation of shellfish in the Atlantic.
Too many of any species anywhere can cause problems, of course. But that's infrequently the case with shark-infested waters - more often, the sharks are simply living in their natural habitats. (Meadows are rarely butterfly-infested, and dolphins seem incapable of infestation.)
Beyond doing a disservice to the feeding behaviors of these fish, shark-infested is yet another mark against a species with more than their fair share of public relations problems. Let sharks teem, abound, bustle or brim. Ban infest.