Asian carp are a group of fish that were brought to North America from East Asia. These fish are not native to the United States or Canada and are considered invasive. They cause serious problems for the environment, ecosystems, economies, and people living in the Upper Midwest and Great Lakes regions of the United States and Canada. The term "Asian carp" refers to several types of cyprinid fish, many of which have become invasive in the United States. These fish are the biggest threat to the health of the Great Lakes.
In December 2014, the United States Department of the Interior and the United States Fish and Wildlife Service gave their first annual report to Congress about the issue. In June 2022, the United States Environmental Protection Agency (EPA) announced a program to rename Asian carp as "Copi." This new name is part of a national and state-level effort to change how the public views these fish. The goal is to promote "Copi" as a healthy and safe seafood option to reduce their numbers in U.S. waterways.
Background
The four main types of Asian carp found in the United States are non-native species that cause harm in their new environments. These species include black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix), and bighead carp (Hypophthalmichthys nobilis).
Black carp eat native mussels and snails, some of which are already endangered. Grass carp are plant-eaters that consume aquatic plants, which can change the balance of food webs by affecting plant, insect, and fish populations. Silver and bighead carp are filter feeders that eat plankton, a vital food source for young fish and mussels.
Silver and bighead carp have become very common in the Mississippi River basin, raising concerns because they compete with native species for food and space. These fish are difficult to catch with typical fishing methods because they do not eat most types of bait.
In the 1970s, fish farmers in southern states began bringing Asian carp from China to help clean their ponds. Silver and bighead carp have grown in number quickly in the Mississippi River basin. While some sources say that floods in the 1990s allowed carp to escape from ponds, this is not confirmed. At least one escape of bighead carp was recorded in 1995, but these species were already in the Mississippi River basin before 1990. Grass carp have been reproducing in the Mississippi River since the 1970s.
The term "Asian carp" is often used to refer specifically to grass, black, silver, and bighead carp. Of the Asian carp introduced to the United States, only two species (crucian and black carp) are not firmly established. Black carp may now be living in the United States, as adult fish have been found in rivers connected to the Mississippi River. In South Florida, sterilized grass carp are used in canals to control the growth of hydrilla, a plant that blocks water systems.
Silver carp are known for jumping out of the water when startled by boats or watercraft. These fish can grow to weigh 100 pounds (45 kg) and jump up to 8–10 feet (2.4–3.0 meters) high, causing injuries to boaters. The Environmental Protection Agency (EPA) reports that injuries include cuts, broken bones, and concussions. Bighead carp do not typically jump when frightened. Some fishing events, such as the Redneck Fishing Tournament in Illinois, use nets to catch jumping silver carp. Groups like the Peoria Carp Hunters have also used the jumping behavior to hunt these fish. Silver carp in North America jump more than their relatives in Asia, but the reason for this difference is not fully understood.
Presence and threats
Bighead, silver, and grass carp are common in the Mississippi River basin, including its tributaries, the Ohio and Missouri rivers. These fish can reach very high numbers, especially bighead and silver carp. They have been found in this area from Louisiana to South Dakota, Minnesota, and Ohio. Grass carp are also present in at least one other area in Texas and may be in other places.
The Environmental Protection Agency (EPA) is worried about Asian carp possibly moving across the Saint Lawrence River divide into the Great Lakes drainage basin. In 2002, the U.S. Army Corps of Engineers (USACE) built an electric fish barrier in the Chicago Sanitary and Ship Canal. This canal connects the Mississippi River drainage basin (via the Illinois River and Des Plaines River) to the Great Lakes Waterway (via the Chicago River) and is the only navigable water link between these basins. The first barrier was a test to study its effectiveness. After positive results, a permanent barrier was built in 2004. USACE also identified 18 sites in five states, from Minnesota to New York, that could allow fish from the Mississippi basin to move into the Great Lakes.
Asian carp have been found in Lake Calumet in Illinois. Grass carp have been caught in every Great Lake except Lake Superior, but no reproducing population has been found. No silver carp or black carp have been found in any Great Lake. Common carp are common throughout the Great Lakes.
A 2012 report by the Great Lakes Commission said that physically separating the Great Lakes and Mississippi River watersheds is the best long-term way to stop invasive species like Asian carp from moving between the areas.
Stopping Asian carp from spreading into Lake Erie is a concern because Lake Erie provides good conditions for the carp to survive. This could harm native fish and hurt the sport-fishing industry, as catching these carp with traditional methods is hard. In October 2013, scientists found that Asian carp had reproduced in Ohio's Sandusky River, a tributary of Lake Erie. A 2015 study showed the serious risks of a carp invasion in Lake Erie.
In May 2013, a test for silver carp environmental DNA (eDNA) in Lake Michigan near Green Bay, Wisconsin, was positive. Scientists retested in May 2014.
In 2016, many Great Lakes charter boat captains asked for quick action to stop the carp invasion. In August 2016, Michigan’s Department of Natural Resources said no Asian carp had been found in their state’s waters or the Great Lakes system.
On December 21, 2009, Michigan’s attorney general filed a lawsuit with the U.S. Supreme Court to close the Chicago Sanitary and Ship Canal and keep Asian carp out of Lake Michigan. The U.S. Army Corps of Engineers and neighboring Great Lakes states were co-defendants.
In response, Illinois’s attorney general filed a counter-suit, arguing that closing the canal would harm shipping and jobs. Michigan said the sport-fishing industry could lose over $3 billion and 4,000 jobs. President Obama supported keeping the canal open, and reports from the U.S. Geological Survey and U.S. Fish and Wildlife Service said Asian carp did not pose a threat.
The Supreme Court rejected Michigan’s request to close the canal in 2010 but did not act on other requests. The lawsuit continued in lower courts.
In 2010, Michigan again asked to close the locks after finding DNA evidence of Asian carp in Lake Michigan, but the request was denied. Four states joined Michigan in a lawsuit against the U.S. Army Corps of Engineers and the Metropolitan Water Reclamation District of Greater Chicago. Their request to close the locks was denied multiple times.
In December 2012, a court dismissed the lawsuit, saying separating the Great Lakes from the Mississippi River basin would violate federal laws requiring navigable waterways. The states were given time to refile the case.
In 2010, Ontario’s government joined the American states in a lawsuit to stop Asian carp from entering the Great Lakes.
The U.S. Geological Survey and the University of Minnesota created a report on using eDNA to detect species in waterways. This followed findings of Asian carp DNA in Minnesota’s Mississippi and St. Croix Rivers in 2011. Later tests did not find Asian carp, though some have been caught in Minnesota. Scientists are unsure why they were not detected again.
In 2011, the National Park Service created an action plan to stop Asian carp from spreading in Minnesota.
The Upper Mississippi CARP Act was proposed in 2013. It would give the Army Secretary the power to use strategies to stop Asian carp and remove them from the environment.
Remediation efforts
Other efforts to reduce the number of Asian carp have included encouraging the public to eat more carp and fisheries shipping the fish to other markets, such as Israel.
As of 2016, there are plans to reintroduce Alligator gar between Tennessee and Illinois as part of an effort to control Asian carp. While gar cannot eat adult carp, they can eat juvenile carp.
The fish response to loud noises ranges from nothing to death. There is short-term avoidance, where fish simply move away from the sound, and long-term avoidance, where fish change their behavior to completely avoid the sound. A fish can also lose its hearing.
The United States Geological Survey is conducting research on the effects that sound has on Asian carp. The obvious connection is how the carp jump out of the water when a boat passes by. The current focus is finding sounds that affect Asian carp but not native fish. One active study, conducted with the U.S. Army Corps of Engineers Engineer Research and Development Center, the University of Minnesota Duluth, and the U.S. Fish and Wildlife Service, found that the noise of a 100 HP boat motor is highly effective. In fact, one study showed that the noise of a boat motor impacted Asian carp and had little to no impact on native fish populations.
Other concerns with using sound include damage to underwater structures, negative effects on navigation, public safety risks, and potential weakening of shorelines.
There are currently plans for a barrier to be built at the Brandon Road Lock and Dam on the Des Plaines River in Joliet, Illinois. It will include electricity, audio sounds, and bubbles as deterrents. The Brandon Road Interbasin Project will cost $1.15 billion. It is believed this project will save the $7 billion annually fishing industry in the Great Lakes.
U.S. Rep. Clay Higgins has been calling for a bounty program since 2018. He believes the program enacted with the Coastwide Nutria Control Program has had good results and thinks it can be used for Asian carp.
Other efforts to reduce the number of Asian carp have included encouraging the public to eat more carp and fisheries shipping the fish to other markets, such as Israel.
Legislation
In July 2007, the U.S. Department of the Interior classified silver carp and largescale silver carp as harmful species under the Lacey Act. In July 2012, Congress added the "Stop Invasive Species Act" to a transportation bill. This law requires the U.S. Army Corps of Engineers to speed up efforts to protect the Great Lakes from Asian carp.
U.S. Representative Dave Camp from Michigan’s 4th district and Senator Debbie Stabenow of Michigan introduced the Close All Routes and Prevent Asian Carp Today (CARPACT) law. This law directs the Army Corps of Engineers to take action to stop Asian carp from entering the Great Lakes. The law estimates that preventing this would cost over $30 million in 2010. The law requires closing and keeping closed the locks and sluice gates at the O'Brien Lock and Dam and the Chicago Controlling Works until a better strategy is created. It also allows the Army Corps of Engineers to improve barriers and monitoring systems by acquiring land needed for construction and maintenance. The Corps can also use fish toxicants, commercial fishing, netting, and harvesting to eliminate and stop the spread of carp. A 2012 report by the Great Lakes Commission stated that physically separating the Great Lakes from the Mississippi River watersheds is the best long-term solution to prevent Asian carp and other invasive species from moving between waterbodies.
In November 2009, scientists found genetic material from Asian carp beyond the two electric barriers, leaving only one lock and dam on the Calumet River between the detected presence and Lake Michigan. Joel Brammeier, acting president of the Alliance for the Great Lakes, said, “This is absolutely an emergency,” referring to the threat to the environment and recreational boaters. He and others called for the immediate closing of the lock, though others questioned whether it was possible to stop shipping traffic there. Jacqueline Y. Ashmon, a spokeswoman for the U.S. Army Corps of Engineers, said, “All options are on the table,” but added, “We don’t have any specifics.”
In December 2009, the U.S. Army Corps of Engineers shut down one electric barrier for maintenance. In response, the Illinois Department of Natural Resources poured 2,200 gallons of the toxin rotenone into the canal. Rotenone is deadly to fish but not harmful to humans, animals, or most other aquatic life. While many fish were killed, only one carp was found near Lockport Lock and Dam, nearly six miles below the electric barriers.
On September 8, 2010, the Council on Environmental Quality announced the appointment of John Goss as the Asian Carp Director. His role is to advise the chair of the Council on Environmental Quality, Nancy Sutley, on Asian carp issues and oversee federal, state, and local efforts to control the carp. Goss previously worked as executive director of the Indiana Wildlife Federation, director of the Indiana Department of Natural Resources, and vice-chairman of the Great Lakes Commission.
The Stop Asian Carp Act of 2011 required the Secretary of the Army to study the feasibility of separating the Great Lakes and Mississippi River Basins using methods like electric barriers. The law gave the Secretary 30 days to begin a study on the best ways to separate the Great Lakes to prevent Asian carp from entering. The study needed to examine techniques that would stop carp from spreading through flooding, wastewater systems, stormwater infrastructure, waterway safety operations, and traffic from barges and recreational boats.
In 2012, the U.S. Senate and House introduced new bills to help stop Asian carp from entering the Great Lakes by accelerating parts of the Stop Asian Carp Act of 2011. The legislation requires the U.S. Army Corps of Engineers to complete their study within 18 months on how to separate the Great Lakes from the Mississippi watersheds.
As food
Asian carp have been eaten as food in Asia for thousands of years. The four most famous species—bighead, silver, black, and grass carp—are among the most eaten fish in the world. In China, these fish have been called the "Four Great Domestic Fishes" since the Tang dynasty (618–907 AD). Some dishes made with carp include "sweet-and-sour carp" and "thick miso soup with carp." However, in North America, the name "Asian carp" is often linked to a different type of carp, the invasive Eurasian carp. This carp eats both plants and animals, lives at the bottom of waterways, and has many bones. It is not commonly eaten in the United States.
The meat of Asian carp is white and is described as tasting like cod and having a texture similar to scallops and crabmeat. Most Asian carp have low levels of heavy metals like mercury because they are mostly filter feeders and herbivores, which means they are lower in the food chain and less affected by harmful substances building up in their bodies. People have worked to increase the popularity of carp by cooking and selling carp-based dishes and using its organs to make fertilizer.
Between 2010 and January 2019, fishermen in Illinois caught 7.5 million pounds of carp from the Illinois River. Most of this catch was used to make bait, fertilizer, and pet food.
As of 2020, there was no market in the United States for Asian carp roe as a substitute for caviar, though efforts to promote it have started in Europe.
In June 2022, the Illinois Department of Natural Resources launched a campaign to rebrand Asian carp as "Copi" as part of a federal and state initiative to encourage people to eat the invasive fish, reduce its population in Midwestern waterways, and stop it from entering the Great Lakes. The U.S. Environmental Protection Agency, through the Great Lakes Restoration Initiative, is funding the Copi rebranding. Copi is now sold in restaurants in Illinois, Arizona, and Washington, D.C., in seven fish markets in Illinois and Tennessee, and by seven fish distributors in Illinois, Michigan, New York, Ohio, Maryland, and Wisconsin. The success of the Copi campaign will be measured by how many pounds of carp are removed from waterways. At the start of the campaign, 6,000,000 pounds of carp removal was expected, with a goal of 12,000,000 pounds in the first year. Within two months of launching, removals exceeded 10,000,000 pounds.
In addition to the EPA renaming the fish "Copi," other rebranding efforts are underway to increase consumption and reduce the number of invasive carp. One campaign, led by the University of Illinois at Urbana-Champaign, refers to the fish as "silverfin" and serves it in different forms, such as smoked, fried, and as sliders, in their cafeteria.
Another campaign, "The Perfect Catch," was planned to begin in summer 2021 with a media campaign. The campaign highlights that the fish has a flaky texture, is low in mercury, and is rich in protein and omega-3s. A nickname for the fish is "Kentucky tuna."
A campaign called "Can't Beat Em, Eat Em" was started by a group of representatives from Louisiana and Illinois. Louisiana chef Philippe Parola, inspired by Chef Paul Prudhomme’s "Blackened Red Fish," developed a cooking method called "blackening" to make the fish more appealing to people.