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Alabama, Arkansas, Colorado, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Virginia, West Virginia, Wisconsin, WyomingEcosystem
Lake, River/streamSince their entry into the lower Mississippi River some 50 years ago, invasive carp proliferated and are now widespread throughout much of the 31-state Mississippi River basin and threaten the Great Lakes. Over the last five decades, as they gradually spread and grew abundant in many areas, invasive carp have depleted the vitality of many rivers, lakes and reservoirs within the Mississippi鈥檚 broad reach. Invasive carp now represent one of the most urgent, wide-ranging and complex environmental challenges of our time.
The term invasive carp refers to several species of related fish that originate from Southeast 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 four of these species: bighead carp, black carp, grass carp and silver carp.
Up and down the Mississippi River waterways and throughout the Great Lakes, the U.S. Fish and Wildlife Service and our partners are working together across the waterscape to protect our environment, our favorite outdoor pastimes and our economic prosperity from the invasive carp threat. Together, we are carrying out more than 80 projects to manage invasive carp.
What makes invasive carp so harmful?
Invasive carp are voracious feeders that grow and multiply quickly and have no significant predators. When they move into an area and become established, they leave a trail of destruction in their wake.
- In the most infested areas, invasive carp wipe out populations of other aquatic species 鈥� from tiny zooplankton and vegetation to mollusks and fisheries 鈥� disrupting the entire food web in aquatic environments.
- Invasive carp jeopardize the safety and quality of our outdoor experiences, causing physical harm to anglers and boaters when they leap from the water and diminishing opportunities for on-the-water recreation where they are abundant.
- Invasive carp have significant economic impacts in communities that rely on certain commercial fisheries and outdoor recreation and tourism-related businesses. They threaten our broader economic stability the more they spread.
Where are invasive carp populations now?
The distribution of each of the four kinds of invasive carp in North America is different. Grass carp are the most widespread and, unlike the others, have populations outside the Mississippi River basin. The bighead carp is believed to have the largest distribution of the three others, with silver carp occupying a similarly broad range. Because black carp are are bottom-feeders, they are harder to find and efforts are underway to get more thorough information on their distribution.
As invasive carp became established throughout the lower Mississippi River, they moved into the major tributaries, including the Arkansas, Red and White Rivers in the lower region, upstream into the Ohio, Tennessee and Cumberland Rivers reaching east and the Missouri River reaching west, and then into the Illinois River toward Lake Michigan. In recent years, they have increasingly spread into the upper Mississippi River region as well.
The population densities of invasive carp vary considerably by species and location and invasive carp are not necessarily established in every location where they are detected. Within the Mississippi River basin, there are still some outer reaches, reservoirs and areas between navigation dams that do not have self-sustaining populations. Many of our projects are focused on holding the line to prevent further spread in areas where there is an existing population front, which is the term we use to describe dense concentrations of invasive carp as they migrate upstream.
The situation with grass carp is different from the other kinds of invasive carp in North America. Unlike the others, there is a known grass carp population in the Great Lakes, specifically in Lake Erie, and they have historically been detected in all the other Great Lakes except Superior. There is currently no evidence to suggest that the Great Lakes are home to self-sustaining populations of bighead carp, black carp or silver carp.
More specific information on each species is available from the U.S. Geological Survey鈥檚 Nonindigenous Aquatic Species Database showing the current distribution of ,鈥�,鈥� and in North America.
What are we doing to manage invasive carp?
Invasive carp management is led by state natural resource agencies working with dozens of other partners, including the U.S. Fish and Wildlife Service, to leverage expertise and resources. Our agency also serves a lead role in administering grant programs to state and federal agencies to support invasive carp management. Our collective efforts vary in different locations and by species, since the four kinds of invasive carp in North America have life-cycle and distribution differences among them.
The main elements of invasive carp management are:
- Conducting targeted mass removal efforts to reduce the abundance of invasive carp populations, decreasing the risk of expansion and inhibiting reproductive success
- Developing deterrent technologies and barriers to block or impede invasive carp movement
- Ongoing monitoring, including in areas invasive carp haven鈥檛 yet reached, to inform management strategies and detect their spread to new areas before they can become established.
Several state natural resource agencies work with commercial fishers and use special methods to remove large amounts of invasive carp from our waterways 鈥� in some states millions of pounds of invasive carp are removed annually. The most intensive efforts are in Illinois, Kentucky and Tennessee, with growing programs in Arkansas, Louisiana, Mississippi and Missouri. States are using a variety of harvest incentive programs to increase participation in removal.
In 2022, the State of Illinois launched a special initiative to further incentivize the partnership with commercial fishers and increase removal. The initiative encourages restaurants and consumers to cook with invasive carp, or 鈥渃opi.鈥� The goal is to develop a new domestic commercial market for these fish that are widely consumed around the world.
Lock and dam sites on the Mississippi River and tributaries have served to slow or impede the spread of invasive carp to some extent, and existing infrastructure at certain sites has been suitable for testing different deterrent technologies. Major deterrent project sites include the Chicago Sanitary and Ship Canal in the uppermost reach of the Illinois River, Barkley Lock and Dam on the Cumberland River in Kentucky and Lock and Dam No. 19 on the Mississippi River near Keokuk, Iowa. In these and other locations, partners are developing and evaluating deterrent technologies such as electric currents, bubble curtains, acoustics or sound waves, light and carbon dioxide. In many other areas in both the Mississippi River and Great Lakes basins, partners are constructing different kinds of barriers to block potential pathways for invasive carp movement.
To help inform all invasive carp management, partners use several methods for ongoing monitoring of existing invasive carp populations and to screen for their presence in new areas. Widespread on-the-water sampling helps us detect new movement early on so we can intervene to prevent invasive carp from becoming established. We also use eDNA sampling 鈥� or environmental DNA 鈥� as an early detection tool and to help guide priorities for where to sample further with more traditional fishing gears like nets and electrofishing. We implant individual invasive carp with coded tags that allow us to track their movement. This technology, as well as hydroacoustics, helps us gather crucial information on invasive carps鈥� life cycle, population status, congregating habitats and movement.
Partnerships for invasive carp management
Nearly 50 natural resource management agencies and others have organized into seven geographic partnerships to most effectively manage invasive carp throughout the Mississippi River and Great Lakes basins. These partnerships are among the largest coordinated conservation efforts in North America.
Six partnerships are based upon sub-basins of the Mississippi River where invasive carp have proliferated. These are organized under the umbrella of the Mississippi Interstate Cooperative Resource Association, known as MICRA. Established in 1991, MICRA unites 28 states and three federal agencies.
MICRA partners originally organized to promote collaboration in managing aquatic species that cross state boundaries. Partners work together to conserve native fisheries and mussels as well as gamefish such as bass and trout. Over the last 10 years, MICRA has significantly strengthened efforts to manage invasive carp. All of MICRA鈥檚 efforts are facilitated through sub-basin partnerships covering the Lower Mississippi River sub-basin; Arkansas, Red and White Rivers sub-basin; Ohio River sub-basin; Tennessee and Cumberland Rivers sub-basin; Missouri River sub-basin and Upper Mississippi River sub-basin.
A growing concern that invasive carp could spread into the Great Lakes spurred the establishment of a seventh partnership in 2010. The Invasive Carp Regional Coordinating Committee brings together 26 members in the United States and Canada. This partnership is most focused on blocking pathways into the Great Lakes basin and managing the Illinois River invasive carp population because of its connection to Lake Michigan through the Chicago area waterway. While partners have been able to hold the line on the Illinois River population, the increasing number of grass carp in Lake Erie is an emerging, urgent concern.
Both regional partnerships produce annual plans describing priority projects underway to manage invasive carp. Currently there are more than 80 projects being carried out through both partnerships at a total cost of nearly $70 million.
Our collective commitment
In addition to the formal members of our regional invasive carp partnerships, scores of other partners provide crucial support, such as conservation groups, outdoor recreation organizations and academic institutions. The Mississippi Interstate Cooperative Resource Association includes 31 partners and the Invasive Carp Regional Coordinating Committee has 26 members. Some organizations are members of both.
