WADENA — Fed by several rivers, the Twin Lakes east of Menagha are home to a diverse assortment of fish.
But those sunfish, crappies, walleye, northern, bass and the occasional trout would be at risk if the Asian carp enter the upper Mississippi River watershed and hog the native species’ food. To help stop the invasive species — and protect Minnesota’s multibillion-dollar tourism industry — both houses of Congress have included a provision in their water resources development bills that would likely close the Upper St. Anthony Falls Lock and Dam in Minneapolis within one year.
Rep. Rick Nolan, a Democrat representing Minnesota’s 8th District, and Democratic Sen. Amy Klobuchar are on the conference committee that is negotiating the differences between the bills, which passed both chambers by wide margins. Nolan said a compromise should be reached early this year, and it will include language that authorizes a closure once the environment and economic impacts are assessed.
Those who enjoy the lakes and rivers of central Minnesota “are the people that are affected,” Nolan said. “The last place to stop (Asian carp) is the lock and dam at St. Anthony Falls. This is an event that happens in Minneapolis that has a profound impact on the rest of the state.”
The bill also includes Nolan-sponsored language that expands the definition of invasive species — currently limited to plant life — to include animals. That would make it easier for federal money to flow to research of Asian carp, zebra mussels and other non-native species.
Experts say the closure would go a long way to prevent the Asian carp from advancing into northern Minnesota, but they caution that more work must be done to protect the rest of the state. Although the river barge industry opposes the measure, most of Minnesota’s congressional delegation supports it, as does the Department of Natural Resources, invasive species researchers, conservation groups and the tourism industry.
According to a poll last summer sponsored by the Stop Carp Coalition, a group of conservation organizations, Minnesotans of all political affiliations agree with the move. Sixty-three percent of those polled said they supported a proposal to “create a physical barrier to stop the carp by closing the locks, or gate, in the Mississippi River in Minneapolis.”
Formidable fish foe
Former New York Mills Superintendent Todd Cameron lives on Big Pine Lake and guides trips around central Minnesota, including to the fishing mecca of the Mississippi watershed, Lake Mille Lacs. He also co-hosts a Perham-based fishing radio show.
“At least (closing down the lock and dam) will buy us some time to figure out other ways and other means to take care of it,” Cameron said. “They are very aggressive in terms of damage they cause and the takeover of the lake. We need to do what we can to stop Asian carp from entering our streams and waters.”
Nick Frohnauer, the DNR’s invasive fish and river habitat coordinator, called closing the lock and dam “the best option for protecting the Upper Mississippi,” along with improvements to the Coon Rapids Dam a few miles upstream.
“The question is, is it inevitable?” he said. “I don’t know. But it’s definitely worth trying to prevent them from getting here. It’s a risk not worth taking”
Even with the closure, boats could transport the fish into the system, he said.
They’ve established populations farther down the Mississippi and in the Missouri River watershed, but so far Asian carp have not developed breeding populations in Minnesota. A U.S. Fish and Wildlife Service worker found a carcass of a silver carp, one of the four species collectively called Asian carp, on a dam near Winona in August, demonstrating the fish are working their way farther up the river.
With help from the University of Minnesota Aquatic Invasive Species Research Center, the DNR is working on other ways to stop the species from spreading to other Minnesota waterways, such as the Minnesota and St. Croix rivers.
“Closing the lock makes a lot of sense, but it does nothing at all to protect the rest of the state,” said Peter Sorensen, aquatic invasive species center director.
Part of what the university is doing is studying the carp to determine their swimming abilities — useful knowledge when plotting a prevention strategy.
“You’d be surprised at how little we know about some of these fish,” Sorensen said.
The center’s research discovered Asian carp are not terrific swimmers, so researchers have started looking at ways to alter the engineering of dams all the way to the Iowa border to increase flow and make it harder for the fish to swim upstream.
So far officials have opted against electric barriers, which have been used in other states, because of the danger to boaters. Other options include attracting the carp with food, then capturing them or rattling the sound-sensitive fish with acoustic barriers.
Besides devastating native fish populations, Asian carp pose a physical threat to humans and equipment, Frohnauer said. The silver can weigh up to 60 pounds and have leapt into boats, maiming occupants.
Barge traffic disrupted
If the Upper St. Anthony Falls Lock and Dam closes, barges would no longer be able to navigate the river north of that point.
While he hopes Asian carp don’t become a problem, Greg Genz questioned whether the closure is worth the cost. The president of the Upper Mississippi Waterway Association, a barge industry organization, fishes the Mississippi southeast of the Twin Cities, a walleye hotspot that wouldn’t benefit from the action.
“I’m scared to death about these fish,” he said. “They completely change your recreation opportunities.”
Genz’s company, Kaposia Marine, provides support services for the river barge industry.
A 2012 Metropolitan Council report found that the closure would lead to the loss of 72 jobs.
Genz said the real cost isn’t to the workforce, but rather to the state’s infrastructure, as the river traffic moves to the roads.
“We’re trying to move traffic off of the highways,” he said, “but this move puts traffic back on the highways.”
Genz said there are dam barriers between St. Cloud and Brainerd that would help prevent carp from making it to those lakes and river systems, but even if they were to invade, the impact has been overblown. “Asian carp will not affect broad swaths of our tourism industry; it will affect boating and fishing.”