They grow to 50-120 pounds, jump like tarpon, and breed so fast that Australians nicknamed them “river rabbits.” They eat so much, they can suck down two or three times their weight in plankton every day.

And now these exotic Asian carp are knocking on the door of the Great Lakes, where biologists fear they could cause environmental changes that would put the zebra mussel to shame.

“In some places on the Mississippi and Illinois rivers, there are so many Asian carp that commercial fishermen gave up trying to fish those pools,” said Jerry Rasmussen, a U.S. Fish and Wildlife Service biologist at Rock Island, Ill.

In 1990, biologists netted no Asian carp when they sampled the Mississippi and Illinois rivers. Ten years later, Asian carp made up 97 percent of a massive fish kill in a Mississippi slough south of St. Louis.

If the carp reach the Great Lakes, the fear is that they will compete for food not only with juvenile game fish but with all the bait fish fry and fingerlings near the bottom of the food chain.