Originally introduced by the U.S. Fish and Wildlife service to control vegetation, Asian carp have overrun the Mississippi River. With no natural predators the fish are reproducing at a alarming rate and now threaten to enter the Great Lakes. Although there are four species, the most famous is the silver carp, which jump out the water en masse when boats pass, often injuring boaters.
No one has been able to find a practical solution to the problem yet, but a few rednecks with a ski boat and and a samurai sword came up with an even better idea. Check it out.