The threat to our waters

At least dozens, and most likely hundreds, of adult invasive carp are now found in the Mississippi River’s Pool 8–just north of the Minnesota-Iowa border in MN/WI waters. They could reproduce at any time. The abundance and activity of invasive carp to our immediate south in Iowa and Illinois highlight why this is a serious concern.

• The Upper Mississippi River and its pools offer a good habitat for carp to reproduce successfully. Large female carp spawn over 1 million eggs annually for many years. Once carp are reproducing in MN waters, there will be lots of them.
• Our waters have few predators for adult carp but offer plenty of food, such as plankton, fish larvae, and mussels. Such conditions would support explosive population growth.
• Dozens of published studies show that, in regions south of MN, invasive carp have greatly impacted local fisheries, ecosystems, and biodiversity.
  • Because carp compete for food and eat larval fish, the number of many river fishes will drop by about one-third as their food is eaten and their young consumed. Both game fish like walleye and plantivorous species such as buffalo will be seriously affected.
  • The size and condition of native fish, such as bass, buffalo, drum, perch, and crappies, will also decline notably.
  • Overall ecosystem health will decline as the diversity and abundance of plankton are reduced. Biodiversity will also decline, with mussel-eating black carp posing a threat to all native mussels.
  • Recreating on the river will not be as enjoyable. Adult silver carp, weighing as much as 40 pounds and able to jump up to 9 feet in the air, pose a serious threat to boaters.

Every ecosystem is different, so the precise impact of carp on MN waters is not yet known. However, there is currently no scientifically valid reason to believe that carps’ effects here will differ greatly from those in regions to the south. Being cautious and proactive seems  advisable. 

There is currently no effective way to control carp. Other states spend millions on mass fishing with limited success. A reproducing population of invasive carp would cause major changes to the Upper Mississippi River ecosystem and biodiversity in MN and WI waters. Their movement upstream must be stopped–while we are still able to do so.