The last boat will pass through downtown Minneapolis next week as the upper St. Anthony Falls Lock and Dam closes for good.
It's part of efforts to stop invasive carp from spreading farther up the Mississippi River. But the move does little to protect Minnesota's other major rivers like the Minnesota and St. Croix rivers.
More invasive carp were caught just south of Stillwater in the past few weeks. That's the farthest upstream they've been detected.
The fish can grow upwards of 50 pounds and crowd out native species.
MPR's Cathy Wurzer spoke with University of Minnesota professor Peter Sorensen, who studies invasive carp with the Minnesota Aquatic Invasive Species Research Center.