State hopeful about blocking Asian carp
BLOOMINGTON — The prospects for blocking Asian carp from the Upper Mississippi River watershed are looking promising.
That’s the gist of where things stand today, according to Steve Hirsch, director of ecological and waters resources at the Minnesota Department of Natural Resources.
Current legislation in Congress would allow for the closing of Lock and Dam One at St. Anthony Falls on the Mississippi River, Hirsch told an audience at the DNR-sponsored Roundtable in Bloomington on Jan. 11.
The legislation is part of the Water Resources and Development Act. It appears likely to pass in both chambers, he said.
“It’s the single best thing the state can do to keep Asian carp out of the Upper Mississippi River watershed,” Hirsch said of closing the Lock and Dam. The closure would again make St. Anthony Falls a natural, geologic barrier to upstream fish migration.
Unfortunately, there is no one, big thing that can be done to block the impending arrival of Asian carp to the Minnesota River system.
And there are very good reasons to believe the invasive carp will find the Minnesota River to their liking.
The fish need a moving, big river for spawning.
They also do well in river systems where there are highly productive side waters — exactly what the Minnesota River also offers, he noted.
Once in the system, it will be impossible to stop their upstream migration for 284 miles to the Churchill Dam at Lac qui Parle Lake. Floodwaters bypass the only other obstruction — the Granite Falls dam — roughly once every four years.
The state is hoping that the arrival of Asian carp into the Minnesota River can be delayed until research provides better tools to manage them. Hirsch also noted that keeping water quality and habitat strong for native species is an important strategy to manage the potential impacts of Asian carp.
In hopes of delaying their arrival, the Minnesota Aquatic Invasive Research Center at the University of Minnesota is seeking funds to look at what can be done at Locks and Dams 2, 5 and 8 on the Mississippi River.
The research would look at whether there are ways to operate the radial arm floodgates at the sites to affect water velocities and make it difficult for the fish to migrate upstream. The research would also look at whether there are already attributes at the sites that are inhibiting upstream colonization by the fish.
Asian carp are currently well-established in the Mississippi River below the lock and dam at Keokuk, Iowa. They are also established in a pool or two upstream. As of now, the carp are not believed to have strong, established populations farther upstream.
Hirsch said there is some reason to believe that the upstream colonization by the fish is a slower process than originally believed, giving hope that Minnesota still has time to take action.
The fish were deliberately released into the U.S. and began showing up in waters where they had not been released in the 1970s.
Nearly four decades later, Minnesota is seeing its first. Four individual Asian carp were documented in Minnesota waters in each of the last two years.
They’ve been periodically showing up in the state’s waters, but there is no evidence that any of the four species of Asian carp has an established population in Minnesota waters, Hirsch said.
“We treat this as one where there is a lot of urgency, but hopefully there is some time to deal with and get some of these things in place,” he said.