A fat, flopping fish with black, beady eyes and an insatiable appetite for plankton seems to have pulled the slip on the United States Army Corps of Engineers.

They haven’t been spotted yet, but environmental DNA tests show that Asian carp have breached an electric barrier designed to keep them out of the Great Lakes. Scientists recently collected 32 DNA samples indicating the presence of Asian carp between the barrier and Lake Michigan in waterways south of Chicago, said Major-General John Peabody of the U.S. Army Corps of Engineers.

Asian carp DNA was found within 12.8 kilometres of Lake Michigan and only 1.5 kilometres south of a navigational lock that is the only remaining obstacle between the carp and the Great Lakes.

Several species of carp were imported from Asia about 30 years ago and used on catfish farms to control algae populations. They soon made an escape into the Mississippi River and have been making their way north ever since.

Along the way, they’ve starved out nearly every other species of fish and earned a reputation as a safety hazard. The carp are sensitive to motion, and will leap into the air when a boat goes past. In 2003 a jet skier broke her nose and nearly drowned when she was struck by a jumping carp.

The arrival of the fish in the Great Lakes could mean the beginning of dangerous new era for water sport enthusiasts and the end of a $7-billion sport fishing industry.

The carp can grow to more than a metre long, weigh more than 45 kilograms, and eat 40 per cent of their body weight in plankton each day. Ecologists predict that they could out-eat every other species of fish in the Great Lakes and cause the collapse of an ecosystem.