Two invasive species have infested one of the state's biggest rivers

Two different invasive species are in it
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Zebra mussels

Zebra mussels

The Minnesota River has now joined the state's list of waters infested with a couple of unpopular invaders. 

The river that drains much of western and southern Minnesota has zebra mussels and invasive carp, the DNR said Thursday.

Zebra mussels were found near the river's source last fall and in recent surveys they showed up as far downstream as New Ulm. There's still no sign of them in the lower stretches of the Minnesota, but since there's nothing to stop their spread, the DNR listed the whole river as infested. 

Meanwhile, two kinds of invasive carp – bighead and grass carp – have made it upstream as far as Granite Falls. 

Just like on the Mississippi and St. Croix, no schools of invasive carp have been found – just individual ones here and there. But the DNR's invasive carp coordinator, Nick Frohnauer, says on the Minnesota River “The tipping point was the recent capture of a large bighead carp with eggs. Although it’s just a few individuals, both male and female fish have been captured. This designation is a precautionary tool to help minimize risks."

Classifying the Minnesota River as infested will mean some changes in how the state gives permits to people who do commercial fishing or harvest bait. But the rest of us aren't immediately affected. 

What's so bad about these invaders?

You can learn more about Minnesota's invasive species here, but the short answer is they crowd out the native fish and mussels because they eat a lot and reproduce fast. 

Zebra mussels also clog water pipes, mess up boat motors, and cut the feet of swimmers. 

Zebra mussels on a motor

Zebra mussels on a motor

Bighead and grass carp wipe out underwater plants and hurt water quality. Their biggest threat to Minnesota, though, is that they could crowd out the sport fish that people come here to catch. 

To limit the spread of invasive species, Minnesota law requires people to clean the plants and other gunk off their boats whenever they leave a lake or river. You also have to drain all the water out of the boat and throw any leftover bait in the trash, not the water. 

The Minnesota River runs 335 miles from Big Stone Lake on the state's western border southeast to Mankato and then northwest to the Twin Cities, emptying into the Mississippi River at Fort Snelling. Take a virtual tour of it here

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