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The Challenge of Invasive Carp

The term “invasive carp” refers to several species of related fish that originate from Asia. As many as ten types of carp are considered invasive around the world, but in the United States and Canada “invasive carp” refers to these four species: bighead carp, black carp, grass carp and silver carp. 

Because they are voracious feeders that grow and multiply rapidly, invasive carp can quickly become abundant and destructive. They consume so much of the nutrient sources from our waters that they disrupt the food web in aquatic ecosystems, destroy habitat and out-compete native fisheries. In the most infested areas, they jeopardize the quality and safety of all kinds of on-the-water recreation. They can also cause significant economic impacts.  

Invasive carp were originally imported into the United States for use in aquaculture ponds and wastewater treatment facilities as a way of controlling the growth of algae and other aquatic vegetation. They found their way into the lower Mississippi River through flooding and accidental releases. As they became established throughout the lower Mississippi River, they surged west into the Arkansas, Red and White Rivers, upstream and into the Ohio, Tennessee and Cumberland Rivers reaching east and the Missouri River reaching west. As they moved further north up the Mississippi, they also spread into the Illinois River toward the Great Lakes. Because of potential access through the Chicago area waterway, bighead and silver carp populations are within striking distance of Lake Michigan. Black carp are present in the lower Illinois River and grass carp have begun to populate western Lake Erie.  

With our Great Lakes economy, environmental values and exceptional on-the-water recreation at stake, the Invasive Carp Regional Coordinating Committee stands united in our efforts to stop the spread of invasive carp. Widespread monitoring informs our overall invasive carp management strategy, which prioritizes targeted mass removal, the use of deterrents and barriers and rapid response when we detect spread to new areas. 

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A U.S. Fish and Wildlife Service staff member driving a motorboat with a hoard of silver carp jumping out of the water in the background.
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Management actions for bighead and silver carp are similar and focus on reducing the abundant populations in the Illinois River. Grass carp is the only one of the four invasive carps with a population in the Great Lakes. We have prioritized intensive monitoring and removal to prevent this population in western Lake Erie from becoming established. Less is known about black carp compared to the others because they are harder to capture, but we are learning more by working with commercial fishers to gather specimens for research. Photo: U.S. Fish and Wildlife Service
March 2026

Upper Illinois River Invasive Carp Status Map

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A map displaying the electric barrier system with a star located 37 miles from Lake Michigan in the Chicago Area Waterway in Northeast Illinois. The leading edge of adult bighead and silver carp is 10 miles below the electric barrier system. The leading edge of potential bighead and silver carp reproduction is depicted as 62 miles away from Lake Michigan in the Marseilles Pool. Verified spawning is shown to be in the Starved Rock Pool, 88 miles away from Lake Michigan.
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The Upper Illinois River Invasive Carp Status Map shows the current population front for various life stages of bighead and silver carp. The adult population front is shown in the Dresden Island Pool, 47 miles from Lake Michigan. The map also notes locations for the following detections:

The 2022 capture of a single silver carp in Lake Calumet.
The 2017 capture of a single adult silver carp above the electric dispersal barrier system, but below T.J. O'Brien Lock 9 miles from Lake Michigan.
The 2015 detections of three larval fish in the Dresden Island Pool. There have been no other detections before or after the 2015 event.
The 2010 capture of a single bighead carp in Lake Calumet.
The 2009 capture of a single bighead carp during rotenone action in the Lockport Pool.

All distances measured in river miles from Lake Michigan (Chicago Harbor). Source: U.S. Army Corps of Engineers Illinois Waterway Navigation Charts

How You Can Help

Everyone plays a role in preventing the spread of invasive carp. Educating yourself and others is key in the fight against these aquatic invaders.

  • Learn the difference between juvenile invasive carp and other young bait fish such as Gizzard Shad.
  • Only use wild-caught baitfish in waters where they came from and don’t move live fish from one location to another.
  • Drain lake or river water from live wells and bilges before leaving any waterbody.
  • Become an ambassador for your watershed by helping others learn these simple steps.
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Juvenile invasive carp identification. Michigan Department of Natural Resources, October 9, 2013