Just 20 Fish Could Overtake the Great Lakes

Twenty fish – 10 mommies and 10 daddies. That's all it could take to establish a population of the invasive and ecologically destructive bigheaded or Asian carp in the Great Lakes, according to a new report out from the Canadian government. And depending on the activity of the females, even fewer than 10 males may be needed to start a population boom in the Great Lakes that would likely be impossible to stop.

The problem with these bigheaded carp is that they are voracious eaters of plankton – the broad base of aquatic food chain – and have no natural predators. They can grow to more than 4 feet and 100 pounds. One particular species has become famous in videos for its tendency to jump high out of the water when near the sound of boat motors. They've already established themselves in the Mississippi and Illinois rivers, in some places accounting for 97 percent of the fish population. If they were to enter and set up shop in the Great Lakes, the region's $7 billion commercial and sport fishing industry could be in serious trouble.