Sophisticated genetic testing in Chicago area waterways has found evidence of the dreaded Asian carp within seven miles of Lake Michigan, federal and state officials said in a cautious note of concern Friday.

The carp apparently leaped over an electrical barrier once called the "last line of defense" for the Great Lakes.

The finding has spurred a crash effort to find the actual fish.

The tests, conducted since August and with findings available in recent days, put the voracious and pernicious invasives one lock and dam away from the Great Lakes.

The testing looks for carp DNA in suspended particles floating in river currents, and for the first time has found evidence of bighead and silver carp in the Calumet River, Des Plaines River and at the confluence of the Calumet Sag Channel and Chicago Sanitary and Ship Canal.

All these locations are above the electrified carp barrier built to stop the transfer of invasive species between the Illinois River system and the Great Lakes, officials said.

Known for their voracious appetite and prolific breeding, Asian carp have eaten their way up the Mississippi and Illinois rivers over 15 years. In the summer, researchers discovered the fish were10 miles closer to Lake Michigan than previously thought, prompting an emergency plan to clean out the Chicago area waterways.