A 19-pound Asian carp has been found near the shore of Lake Michigan, above a navigation lock that regional political leaders had been demanding the Army Corps slam shut to try to keep the invaders out of the world's largest freshwater system.

The fish confirms what DNA evidence had been telling fishery managers for months - that Asian carp had indeed breached an electric fish barrier on the Chicago Sanitary and Ship Canal, considered the last line of defense for Lake Michigan.

The bighead - nearly 3 feet long - is the first actual Asian carp found above the barrier, despite weeks of netting on the canal system and a $1.5 million fish-poisoning program last month.

It was plucked Tuesday from Lake Calumet, about six miles downstream from Lake Michigan, by a commercial fisherman hired by the state of Illinois to do routine fish sampling in the area.

"We set out earlier this year on a fact finding mission and we have found what we were looking for," John Rogner, assistant director of the Illinois Department of Natural Resources, said in a news release Wednesday. "This is important evidence and the more information we have about where Asian carp are, the better chance we have of keeping them out of the Great Lakes."

The federal government said it has no intention to order shut two navigation locks in the area, something regional politicians outside Illinois have been demanding for months.

The plan is to continue "sampling actions" in Lake Calumet, which is north of the O'Brien lock, as well as other areas on the Chicago canal system. This will involve netting and electrofishing.

Biologists say a handful of fish making their way into Lake Michigan does not mean a self-sustaining population is going to get established. They say most initial invasions fail because the fish must find a suitable place to reproduce, then they must find each other and then their offspring must survive long enough to reproduce on their own. Then, of course, the cycle has to repeat itself. Over and over.

"We remain firmly committed to achieving our collective goal of preventing Asian carp from becoming established in Great Lakes waters," said Mike Weimer, U.S. Fish and Wildlife Service assistant regional director of the fisheries and aquatic resources program.

Meanwhile, federal officials say they will do their best to keep it business-as-usual for the barges, tour boats and recreational boat owners who use the navigation locks to move between the waterways and Lake Michigan.

"The Army Corps of Engineers will continue to operate the locks and dams in the Chicago Area Waterway System for congressionally authorized purposes of navigation, water diversion and flood control," said Col. Vincent Quarles of the U.S. Army Corps of Engineers.

'Worst fears' realized

Michigan Attorney General and gubernatorial hopeful Mike Cox said the find means that the region's "worst fears" have been realized, and he is considering further legal action.

The Republican led a coalition of Great Lakes states this year, including Wisconsin, in a push to reopen a decades-old U.S. Supreme Court lawsuit over of the operation of the Chicago Sanitary and Ship Canal.

He wanted the court to order the locks shut, something the court declined to do.

"President Obama and the Army Corps of Engineers have simply refused to take the threat seriously," Cox's office said in a statement.

But the news came as a relief to an industry group that depends on the navigation locks, which Army Corps officials say were never designed to be used as fish barriers.

"As the government's own studies have shown, lock closure undermines the resources and regional support necessary to solve this problem, while doing nothing to protect the Great Lakes," said Mark Biel, executive director of the Chemical Industry Council of Illinois.

Not necessarily a breach

Biel also said the fish find doesn't necessarily prove there has been a breach at the electric fish barrier downstream on the Sanitary and Ship Canal, a sentiment echoed by Rogner of the Illinois DNR.

Rogner said in a Wednesday conference call with reporters that he is not convinced the fish made it to Lake Calumet on its own. He noted that in the past decade there were two occasions where Asian carp were found in Chicago lagoons, bodies of water not connected to Lake Michigan. Those fish likely were planted by individuals - live bighead were once commonly sold in Asian fish markets in the Chicago area.

Of course, Rogner said, it is also possible the fish somehow swam through the barrier; the Army Corps did not turn up the fish-shocking device to a level strong enough to repel all sizes of Asian carp until the middle of last year, when the first DNA tests indicated the fish were mustering in an area just below it.

Conservationists Wednesday said they weren't surprised by the news.

"The (environmental) DNA has told us for months that the threat is real. It's time to stop fighting about whether there's a problem and move on to developing real solutions," said Thom Cmar of the Natural Resources Defense Council. "Asian carp are like cockroaches. If you find one, you likely have a much larger problem on your hands."

