5 Invasive Species That Might Conquer the World

Asian Carp

There you are, puttering serenely down the river or across a lake, when suddenly the water around you erupts in a frenzy as immense, prehistoric-looking fish begin jumping and thrashing about. One flies right at you, smacking you in the face and leaving you with a real shiner. Sound idyllic? Hardly. Such "attacks" are one of the many problems posed by Asian carp.

Native to China and parts of Southeast Asia, Asian carp were introduced into the southeastern United States more than 20 years ago to clear algae from catfish ponds. Since then, the fish -- known for their ravenous appetites -- have worked their way up the Mississippi and Illinois Rivers, devouring so much plankton and other organisms that there's little left for the native species. Add to that an insanely high reproductive rate and few natural predators, and you can see why they're quickly decimating all the native fish species in their path. Now they're poised to enter the Great Lakes -- an area already compromised by non-native sea lampreys, plus zebra and quagga mussels -- where many fear they'll ruin the lakes' $7 billion fishing and tourism industries [source: Harrison].

But it's not just the Great Lakes that are endangered. The fish are also in the Kansas River and threatening to swim into the Arkansas. Plus, they're causing similar problems in Eastern Europe [source: Pearce]. And who knows where these giant fish -- some top 100 pounds (45.4 kilograms) -- will swim from there [source: WebEcoist]?

One bright spot: Asian carp are a delicacy in China, where they're increasingly rare, due to overfishing. Some Midwestern fishermen are now catching these fish and selling them back to China [source: WebEcoist].

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