Asian carp from Lower Wisconsin River (copy)

Wisconsin DNR fisheries supervisor David Rowe, left, and technician Alex Bentz display one of the bighead Asian carp captured during the department's fall sturgeon surveys on the lower Wisconsin River. The invasive and destructive fish is stopped by the Prairie du Sac dam from getting further up the river.

WISCONSIN DNR/Contributed

Wildlife officials aren’t worried about voracious Asian carp invading the Wisconsin River north of Prairie du Sac because a large dam blocks their way.

A similar solution is needed in a shipping canal near Chicago so the invasive species doesn’t infest Lake Michigan and the Great Lakes.

Specifically, the Brandon Road Lock near Joliet, Illinois, should be shut down to separate the Mississippi River Basin from the Great Lakes, as nature intended.

The attorneys general of three Great Lakes states — Republican Bill Schuette of Michigan, Democrat Lori Swanson of Minnesota and Democrat Josh Shapiro of Pennsylvania — last week urged the U.S. Army Corps of Engineers in Chicago to close the lock and replace it with a concrete structure.

That’s the most effective, least expensive and quickest solution to stopping the Asian carp from advancing farther north, the attorneys general correctly stressed.

Wisconsin officials should add their voices and clout to this bipartisan effort to protect the Midwest’s precious waterways.

Wisconsin was previously part of a lawsuit against the federal government seeking permanent closure of the Chicago canal, and it shouldn’t back down now.

Asian carp escaped decades ago from Southern fish farms and have been moving north ever since. In some northern Illinois waterways, Asian carp now make up 90 percent of the concentration of fish. With their large size and appetites, they crowd out and decimate the sport fish anglers love to catch, such as walleye and bass.

Even a relatively small number of Asian carp reaching Lake Michigan through the Chicago canal system could eventually spread across the Great Lakes. And the man-made canal leading from the Illinois River to Lake Michigan has shown vulnerabilities.

Electric shock barriers in the water have been breached by smaller fish, according to a federal study last year. And an adult bighead carp was caught last spring in the Chicago waterway well past the barriers and only 9 miles from Lake Michigan.

“In the absence of more effective action, they will move through the Brandon Road Lock and the Chicago waterway in sufficient numbers to ultimately invade the Great Lakes, causing devastating ecological and economic damage,” the attorneys general of Michigan, Minnesota and Pennsylvania wrote last week to the U.S. Army Corps of Engineers.

They’re right.

The Army Corps of Engineers has highlighted the potential cost to the shipping industry if products must travel over land rather than on barges in the canal. We understand that concern.

But the cost to the Great Lakes’ fishing and tourism industries would be much greater should Asian carp take over the world’s largest supply of fresh water.

The best solution is a permanent barrier that will stop the Asian carp for good.