When you mention invasive carp, people nowadays probably think of bighead and silver carp — those flying fish we're trying to keep out of Minnesota waters.
But the common carp that's already here is an invasive species, too, and an undesirable one at that. It destroys aquatic plants and stirs up sediment, degrading water quality. Researchers in the north metro area are learning more about these fish as they try to come up with new ways to manage them.
GARRISON, Minn. — Along the rocky shore of Mille Lacs Lake on a recent morning, flat-bottomed fishing boats were idle in their docks. No customers wandered into a bait shop selling night crawlers, minnows and jumbo leeches. The restaurant at Twin Pines Resort was hushed and nearly empty, despite the postcard-perfect views of the vast, sparkling lake it offers from the patio.
And it was no mystery why. That morning, it had become illegal to fish here for walleye, the most treasured fish in Minnesota, on Mille Lacs Lake, perhaps the most famous place in the state to fish for it. Only a few days into August, summer on the lake seemed to be over.
“This is a walleye lake,” said Diane Emery, manager of the Blue Goose, which offers guided fishing trips, last week. “There’s no walleye, there’s no fishermen.”
People keep catching bighead carp in the St. Croix River. After the news this summer that a number of the invasive fish, which could decimate the river’s ecology, have been caught in Bayport, more reports continue to come in.
At the same time, action is happening elsewhere to protect precious waters from the fish. In June on the Mississippi River, the St. Anthony Falls lock and dam in Minneapolis was permanently closed, shutting down the city’s shipping industry in an effort to block carp from getting farther upstream.
A secret river runs through Minneapolis and St. Paul.
Almost no one knows that 30 feet beneath the surface of the languid Mississippi there are rapids. Not just a murmuring riffle or two, but a magnificent, roiling whitewater that once thundered for eight miles over massive boulders, around small islands and through the great river’s only high-banked gorge on its way from St. Anthony falls to Fort Snelling.
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.
Five bighead carp have been caught in the past week in the St. Croix River just south of Stillwater — the furthest upstream the invasive fish have been detected and the largest number caught in the St. Croix to date.
There is no evidence that the fish are reproducing in the river system, but the presence of multiple carp raises the level of concern “up a notch,” said Nick Frohnauer, invasive fish coordinator at the Minnesota Department of Natural Resources (DNR).
“It’s a concern, but we have a strong monitoring program that’s been out there looking for these fish in all their life stages,” he said.
Five Asian bighead carp have been caught recently on the St. Croix River near Stillwater, the farthest north the invasive species has been found on the river, the Minnesota Department of Natural Resources reported Tuesday.
The fish were caught about seven miles upstream of the previous point where they had been confirmed.
The catch more than doubles the four bighead carp that had previously been caught in the river. One carp showed up in 1996 and three others were found in 2011.
Fishermen are usually overjoyed to pull a big one into the boat, but five fish caught just south of Stillwater in the past week have both anglers and wildlife officials concerned.
The Minnesota Department of Natural Resources (DNR) says fishermen and DNR personnel pulled five bighead carp from the St. Croix River not far from Xcel Energy's King Power Plant.
This is the furthest upstream invasive carp have been detected in the St. Croix, some seven miles north of the previous point.
In the movies, science happens fast. A plague that threatens all life? One person finds the antidote, spends a few hours in a lab and — boom! — problem solved. An asteroid headed for Earth? A heroic scientist is able to break into a secured computer, punch a few keys and — presto! —threat averted.
Unfortunately, that’s not how it works in real life, especially with a complicated challenge like aquatic invasive species.
A quarter-century ago, there was some spirited debate about whether Minnesota should become the 28th state to have a lottery.
Local proponents said lottery proceeds would be a way to fund state projects without raising taxes. Opponents argued the expansion of gambling through a state-sponsored lottery was “Un-Minnesotan.”
Ultimately voters approved a constitutional amendment authorizing a lottery for Minnesota in November 1988, with the measure passing with 57 percent of the vote.