The decade-old battle to keep Asian carp out of the Great Lakes might be over.

New research shows the fish likely have made it past the $9 million electric fish barrier on the Chicago Sanitary and Ship Canal, a source familiar with the situation told the Journal Sentinel late Thursday.

The barrier is considered the last chance to stop the super-sized fish that can upend entire ecosystems, and recent environmental DNA tests showed that the carp had advanced to within a mile of the barrier. [img_r]http://media.journalinteractive.com/images/spcl-lakecarp.jpg[/img_r]

That research backed the federal government into a desperate situation because the barrier must be turned off within a couple of weeks for regular maintenance. The plan is to spend some $1.5 million to temporarily poison the canal so the maintenance work can be done.

But even as those plans are being finalized the news everyone dreaded came: It might be too late.

Now the only thing left standing between the fish and Lake Michigan is a heavily used navigational lock.

Army Corps officials declined to comment on the situation.

"I am not prepared to discuss this today, but I will be prepared to discuss this tomorrow," Col. Vincent Quarles, commander of the Chicago District of the Army Corps of Engineers, said when asked about news that the fish had breached the barrier.

The Army Corps, along with its state and federal partners in the barrier's design and operation, has scheduled a news conference for 10 a.m. Friday.

The fish that can grow to 50 pounds or more are a big deal because they are voracious feeders, overwhelming native species, and they pose a huge hazard to recreational boaters because of their habit of jumping out of the water when agitated by the whir of a boat motor.

No fish have been found, but a new type of DNA testing that can show the presence of fish in the water shows that the barrier does not appear to have worked at stopping all the fish.

"We've got some bad problems," Dan Thomas, president of the Great Lakes Sport Fishing Council, said when told the news.

Thomas said the plan to poison the canal is going to have to grow to cover areas above the barrier, which is about 20 miles downstream from the Lake Michigan shoreline.

"Unless we treat that canal real quick as far up as we can, then we can almost be assured that they're on their way into the lake," he said.

For several years, the northern migration of the silver carp had stalled in a pool just above the Dresden Island Lock and Dam on the Des Plaines River southwest of Joliet, Ill. - about 20 miles downstream from the barrier.

In August, the Journal Sentinel learned the environmental DNA testing that biologists had quietly begun using on the canal revealed that the fish had started to move again. It's been all hands on deck ever since.

In addition to plans to poison the river, the Army Corps is scrambling to build a twin to the new barrier. It also is looking at building an emergency berm to prevent the fish from riding floodwaters from the carp-infested Des Plaines River into the canal above the barrier.

The two species of Asian carp threatening to invade Lake Michigan are silver and bighead carp. It's not known which species - or whether both species - have been detected above the barrier with DNA tests.

Silver carp are considered the bigger threat to the economy, ecology and culture of the Great Lakes because of their penchant for leaping out of the water and injuring boaters.

Silver carp were imported to Arkansas in the 1960s where they were used in federally funded sewage treatment experiments.

They escaped their containment ponds soon thereafter and have been swimming north since.