MACKINAC ISLAND, Mich. (AP) — Illinois Gov. Pat Quinn said Saturday that separating the Great Lakes and Mississippi River systems is the "ultimate solution" to prevent voracious Asian carp from overrunning the lakes, a potential step toward resolving a longstanding regional feud.

During a meeting with governors of several neighboring states, Quinn said it would be a massive and costly undertaking to rework the Chicago canal project that linked the two giant watersheds a century ago. He defended Illinois' efforts to block the advance of silver and bighead carp toward the lakes by hiring commercial fishermen and operating an electric barrier, but acknowledged more needs to be done.

"Ultimately, I think we have to separate the basins," Quinn said. "I really feel that is the ultimate solution."

His comment during a Council of Great Lakes Governors panel discussion on this Lake Huron resort island drew applause from government officials, environmental advocates and others in attendance. "I hope you're clapping when Congress comes to invest the money," Quinn said. "It has to be a national project."

But Indiana Gov. Mike Pence, a Republican whose state has sided with Illinois in opposing separation, told reporters his position had not changed. It would "cost thousands of Hoosier jobs and cause additional harm to many Hoosiers to manufacture and grow our products," Pence said. "It's important that we deal with this issue but it's also important that we deal with it in a way preserves the logistical advantages and opportunity to move commerce through our region."

Asian carp were imported in the 1970s to cleanse Deep South aquaculture and sewage treatment ponds. Some escaped during floods and have migrated northward in the Mississippi River and its tributaries. They have advanced to within 55 miles of Lake Michigan in the Illinois River, which connects with a shipping canal and other waters that reach Lake Michigan.

The Great Lakes region has been sharply divided over how to deal with the threat. Michigan went to court in an unsuccessful effort to force closure of Chicago-area shipping locks, then joined four other states — Wisconsin, Minnesota, Ohio and Pennsylvania — in a lawsuit against the U.S. Army Corps of Engineers and Chicago's water district, claiming their refusal to physically separate the watersheds was creating a public nuisance. A federal judge tossed out the case in December.

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Indiana and Illinois have contended that separation would boost flood risks and disrupt water tourism and commercial shipping in the busy metro area. They say the electric barrier in the shipping canal is keeping the carp at bay. But scientists have detected Asian carp DNA in dozens of water samples collected farther upstream, some just a few miles from Lake Michigan.

Quinn told reporters that any separation project would have to address economic and safety concerns. He said he was "intrigued" by a 2012 study that proposed three alternatives for placing dam-like structures in the Chicago waterways. The Great Lakes Commission estimated the price tag would range from $3.2 billion to $9.5 billion.

"I personally favor rigorous study of what the costs are and what has to be done in order to carry it out," said Quinn, a Democrat. "There's no question it would be a very expensive endeavor. But if it's necessary to have clean water in the Great Lakes in the 21st century, it's worth looking at."

Even though he stopped well short of endorsing a particular plan, many at the conference described Quinn's embrace of the separation idea as significant.

"I think it's great to see people talking about longer-term solutions," said Rick Snyder, Michigan's Republican governor. Chris Kolb, president of the Michigan Environmental Council, called it "a very positive step forward."

"There's been so much rancor and disagreement about this issue," said Joel Brammeier, president of the Alliance for the Great Lakes, a Chicago-based environmental group. "To hear Gov. Quinn make a point of bringing it up in this forum speaks volumes."