Apparently, in Illinois they have an infestation of Asian Carp in their rivers.
Asian Carp can grow to 100 pounds in mass, and have become notorious for being easily frightened by boats and personal watercraft, which causes them to leap high into the air. The fish can jump up to 8–10 feet into the air, and numerous boaters have been injured by collisions with the fish. According to the EPA, “reported injuries include cuts from fins, black eyes, broken bones, back injuries, and concussions.”
Therefore, (logically!) they’ve taken a dangerous nuisance and turned it into a sport.
On the plus side, as opposed to most carp, apparently this behemoth makes for good eating!