The New York Times reports that the non-native Asian Carp have made it past a protective barrier and could be on their way to invading the Great Lakes.
When organisms are introduced into a new habitat where they have no natural predators, they can do serious damage -- the population can grow uncontrollably and they can push out native species. Kudzu, which was introduced to the United States from Japan in 1876, is now considered a pest weed, growing out of control throughout the Southeast and expanding every year. And in Hawaii, where nights used to be quiet, an infestation of non-native tree frogs is filling the forests with a maddening noise (and since there are no natural predators for the frogs, there are a lot more voices in the chorus).
So what's the big deal if Asian Carp get into the Great Lakes? Well, not only would they interrupt the natural balance of the food chain, and threaten other species... they also have a very curious habit, one that looks like it might be a little bit of a nuisance:
Check out this CBS report on the invasion.