Here in the Upper Midwest, one of the more notorious invasive species is the flying carp, and for residents of the Great Lakes, the enemy is at the gates.

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

New research shows the super-sized fish likely have made it past the $9 million electric fish barrier on the Chicago Sanitary and Ship Canal

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

Dave Dempsey at Planetsave quotes an official who points out that no actual carp body has yet been found beyond the barrior. Once that happens, of course, it’s pretty much too late.

Last-ditch efforts to stop the carp could include poisoning the entire canal. That’s an extreme measure, and there’s already reason to wonder if it could be done fast enough.