Streaking silver carp swimming from La Crosse to Winona raises invasive concerns

Carp Photo
Carp can reach as much as 20 to 40 pounds, experts say. This photo is not the tagged carp that raised concern. (Minnesota DNR photo)

LA CROSSE (WKBT) — A speedy silver carp that shrugged off the swift current of the swollen Mississippi River to zoom about 35 miles from La Crosse to Winona, Minn., is propelling a call to arms to thwart the invasive species.

The battle line must be drawn just above Lock and Dam 5 about 10 miles northwest of Winona, says one expert, who has a plan that could cost as much as $16.5 million.

The Minnesota Department of Natural Resources tagged the rogue fish, which took advantage of a high-water loophole last month to slip the surly bonds of locks and dams as spillways opened.

The DNR released a report to environmental groups last week showing that the fish navigated roughly 35 miles upriver against strong current and traveled about 35 miles from La Crosse to just north of Winona in less than a day.

That is the farthest north a tagged silver carp has made it in the Mississippi, although though some silvers and other invasive carp species have been caught upstream, DNR invasive fish consultant Grace Loppnow told the Minneapolis StarTribune.

This particular carp’s northward progress adds urgency to the need to block the fish, University of Minnesota professor Peter Sorensen told the StarTribune.

The mostly likely place to stop the surge is at Lock and Dam 5 just above Winona, Sorenson said.

“It’s the day of reckoning, in a way,” said Sorenson, who has made a career of studying carp and has found the carp in the pool of the lock, with only a gate preventing increasing invasion.

The Stop Carp Coalition raised concern in 2020, when a comercial contractor netted 51 silver and grass carp in the Mississippi near La Crosse.

Coalition co-chair Christine Goepfert said the advance of the tagged silver carp has created an urgent moment, which should inspire the state to act quickly.

“It’s like sounding the alarm,” she said. “It’s time to move on.”

In April 2021, the Wisconsin Department of Natural Resources launched 10 boats near La Crosse with crews whose goal was to get a head count — no pun intended on the presence of bighead carp.

“What we’re attempting to do is assess how many silver and bighead carp are out in certain sections of the Mississippi River,” Jordan Weeks told News 8 Now at the time.

Commercial fishermen have caught increasing numbers of Asian carp in recent years, said Weeks, who added, “And it’s a little bit concerning.”

The problem stems in part to the time when private fish farms in the South that contained Asian carp flooded, releasing them into rivers.

The invaders wreak havoc with the environment, experts say.

“Any time you have invasive species that move into an area, there’s potential to push out the native species,” environmentalist Hallie Rasmussen told News 8 Now last year.

“It changes the whole dynamic of the ecosystem,” said Rasmussen, visitors services manager at the La Crosse District Office of the Upper Mississippi River National Wildlife and Fish Refuge

It also creates danger for anglers, because silver carp can weigh 20 to 40 pounds pounds and can leap high out of the water.

“If you’re driving a boat motor and you come across a large school of these things, they may jump out of the water,” Weeks said.

“Individuals could get hit with these fish and potentially become injured,” Weeks said.

All the more reason for DNRs to jump into action, the experts say.

Lock and Dam 5 is the most likely place to halt the migration because there isn’t a large spillway that would allow carp to swim around the structure, according to Sorensen.

He and a group of engineers had a brainstorm about one method that might work — a wall of bubbles and noise known as a “bioacoustic fish fence” to span the lock pool and make the carp retreat.

The Minnesota DNR needs to evaluate a slew of possible solutions besides Sorensen’s plan, Loppnow told the StarTribune.

Another factor adds urgency, according to Colleen O’Connor Toberman, land use and planning program director for Friends of the Mississippi River. If the DNR moves rapidly and outlines the next steps in its strategy, if could ask for funding for a barrier at Lock and Dam 5 this fall and possibly secure a spot in the state budget, she said.

If not, the DNR would have to wait another two years to get into the Gopher State’s biennial budget.
An engineering report Sorensen produced for his proposal estimates the cost at between $8.25 million and $16.5 million.

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