Asian carp is a grouping of fishes commonly used to mean silver, bighead carp, white and black amur, which are regarded invasive in the United States. These four species, also known as copi, are native to China where they are collectively known as qing cao lian yong (青草鲢鳙) or si da jia yu (四大家鱼, "Big Four domesticated fish") and are farmed for food.
Common carp, amur carp and crucian carp are also common food fishes in China and elsewhere. Goldfish, though, are cultivated mainly as pet fish.
These four fish have been cultivated in aquaculture in China for over 1,000 years.
Bighead and silver carp are the most important fish, worldwide, in terms of total aquaculture production.[1]
Asian carp are big fish, with black amur adults grow as big as 33 lbs (15 kg) in average, with the biggest one weighing 150 lbs (70 kg).
Bighead and silver carp are able to breed and produce offspring.
Silver carp are easily frightened by boats, which cause them to leap between 2.5- into the air, and numerous boaters have been severely injured by collisions with the fish.[2] According to the Environmental Protection Agency, "reported injuries include cuts from fins, black eyes, broken bones, back injuries, and concussions".[3] This behavior has sometimes been attributed to the very similar bighead carp, but these do not normally jump when frightened. Catching jumping carp in nets has become part of the Redneck Fishing Tournament in Bath, Illinois.[4]
The grass carp (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus) as well as common carp (Cyprinus carpio) are popular targets for recreational fisherman in the Midwest, despite their status of being an invasive species. These species are unique because of their ability to be caught with the traditional fishing technique of using a fishing rod, reel and a hook.[5] Other invasive carp species – the Silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) are not traditionally caught on rod and reel because they feed on plankton, therefore they do not bite on baited hooks or lures.[6]
Asian carp have been a popular food fish in Asia for thousands of years. In North America, the various Asian carp are often lumped with the common carp and seen as undesirable trash fish because of the unpopularity of common carp as food in this region.[7] Furthermore, even the common carp, which was introduced to North America from Europe in the 17th century, are important food fish outside North America.
The pearly white flesh — though complicated by intermuscular bones — has a mild taste. The filter-feeding silver and bighead carp have much lower heavy metal contamination (such as mercury) than most other fish because they are algivorous primary consumers that do not eat other aquatic invertebrates or fishes and therefore are the least impacted by biomagnification.
A famous dish in Hangzhou called Xi Hu cu yu, traditionally made of white amur, is a dish of controversial flavor.
Copi is available in restaurants in Illinois, Arizona and Washington, DC.; in 7 fish markets in Illinois and Tennessee; and through 7 fish distributors in Illinois, Michigan, New York, Ohio, Maryland and Wisconsin.[8]
There are companies making pet food using silver carp in the US and Canada.
Yuquan, one of the well-known scenic spots in Hangzhou, has a large fish pond alive with hundreds of fish of various colors. As of 2022, many of the fish there are black amur, with additional bighead carp, nishikigoi, sharpbelly and white amur. A three-character inscription, Yu Le Guo, meaning "fish's paradise", is set above one end of the pond in the calligraphy of a famous gentry-scholar of the late Ming Dynasty named Dong Qichang .
See main article: article and Asian carp in North America.
Some species of Asian carp cause harm when they are introduced to new environments. The black carp feeds on native mussels and snails, some of which are already endangered. Grass carp can alter the food webs of a new environment by altering the communities of plants, invertebrates, and fish. Silver carp feed on the plankton necessary for larval fish and native mussels.[9]
Bighead and silver carp feed by filtering plankton from the water. The extremely high abundance of bighead and silver carp has caused great concern because of the potential for competition with native species for food and living space. Because of their filter-feeding habits, they are difficult to capture by normal angling methods.
In the late 19th century, the common carp was distributed widely throughout the United States by the United States Fish Commission as a foodfish.[10] In the 1970s, fish farmers in mostly southern states began importing Asian carp from China to help clean their commercial ponds.[11] [12] The rise in the populations of bighead and silver carp has been dramatic where they are established in the Mississippi River basin.[13]
Because of their prominence, and because they were imported to the United States much later than other carp native to Asia, the term "Asian carp" is often used with the intended meaning of only grass, black, silver, and bighead carp. In the U.S., Asian carp are considered to be invasive species. Of the Asian carp introduced to the United States, only two (crucian and black carp) are not known to be firmly established. Crucian carp is probably extirpated.[14] Since 2003, however, several adults, fertile black carp have been captured from the Atchafalaya and other rivers connected to the Mississippi River.[15] Dr. Leo Nico, in the book Black carp: Biological Synopsis and Risk Assessment of an Introduced Fish, reports that black carp are probably established in the United States. In South Florida, the local water management district actually stocks the canals with sterilized grass carp to control the hydrilla plant, which tends to block the locks and drainage valves used to control water flow from the Everglades.
Bighead, silver, and grass carp are known to be well-established in the Mississippi River basin (including tributaries), where they at times reach extremely high numbers, especially in the case of the bighead and silver carp. Bighead, silver, and grass carp have been captured in that watershed from Louisiana to South Dakota, Minnesota, and Ohio. Grass carp are also established in at least one other watershed, in Texas, and may be established elsewhere.
Grass carp have been captured in all of the Great Lakes except Lake Superior, but so far, no evidence indicates a reproducing population. No silver carp or black carp have yet been found in any of the Great Lakes. Common carp are abundant throughout the Great Lakes.
A few bighead and grass carp have been captured in Canada's portions of the Great Lakes, but no Asian carp (other than common carp) is known to be established in Canada at this time. Concerns exist that the silver carp may spread into Cypress Hills in Alberta and Saskatchewan through Battle Creek, the Frenchman River, and other rivers flowing south out of the hills into the Milk River. Ontario does not have Asian carp yet and has used the provincial Invasive Species Act[16] to prohibit their import.[17]
In Mexico, grass carp have been established for many years in at least two river systems, where they are considered invasive, but no other Asian carp are known to have been introduced.
These fish are thought to be highly detrimental to the environment in parts of the United States.[18] Because of these concerns, the U.S. Fish and Wildlife Service convened stakeholders to develop a national plan for the management and control of invasive Asian carp (referring to bighead, silver, black, and grass carp).[19] The plan was accepted by the National Aquatic Nuisance Species Task Force in the fall of 2007.
As of 2016, efforts were being made to reintroduce alligator gar between Tennessee and Illinois as part of an effort to control Asian carp.[20]
In 2019 the Kentucky declared "War on Carp" and started to use electro-fishing and sonic devices to remove 5 million pounds of Asian carp from Lake Barkley and Kentucky Lake.[21]
Electro-fishing has become an extensive technique in population management of Asian carp throughout the Midwest's river systems. It involves the use of electric waves that stun (non-lethally) the invasive fish at the surface of the water, where fisherman can then corral them into net and remove from the ecosystem. Electro-fishing is also safe for the native species of fish that cohabit the waters where it is implemented, because they avoid the electro-fishing boats by diving deeper into the water column, where as the carp jump near the surface, getting stunned in the process.[22]
There have been conclusive results that have proven electro-fishing to be an effective and efficient way to manage the Asian carp invasion in Midwestern waterways. A typical electro-fishing boat can shock 100 carp per minute of fishing utilizing 110-500 volts of electricity, the fish captured are then humanely killed, and used as food or fertilizer for crops.[23] However, the technique has sparked questions about potential negative impacts that it may have on the rivers' ecosystems. If electro-fishing boats go over spawning grounds for native fish, it could potentially cause harm to fish embryos.[24]
In June 2022,[25] the Illinois Department of Natural Resources announced a campaign to rebrand Asian carp as Copi, which is a clipping of "copious", referring to the large amount of the fish in the US.[26] This branding work was completed in 2022 by Span. The Copi renaming is a part of a Federal and state initiative to get the public to eat the invasive fish,[27] decrease its numbers in Midwestern waterways,[28] and prevent its introduction to the Great Lakes.[29]
The United States Environmental Protection Agency (EPA)'s Great Lakes Restoration Initiative (GLRI)[30] is funding the Copi rebrand of Asian carp.[29]
Success of the Copi rebrand of the invasive fish will be measured using pounds of removal as the key metric. Removal was projected to total 6,000,000 lbs at launch of the Copi rebrand, and increase to 12,000,000 in the first year following. Removal at 2 months from launch exceeded 10,000,000 lbs, on pace to beat year 1 projections.[31]
The Stop Asian Carp Act of 2011 was introduced to require the Secretary of the Army to study the feasibility of the hydrological separation, such as electric barriers, of the Great Lakes and Mississippi River basins.[32] The act provided 30 days for the Secretary of the Army to begin a study on the best means of implementing a hydrological separation of the Great Lakes to prevent the introduction of Asian carp. The study requirements included researching techniques that prevented the spread of carp from flooding, wastewater and storm water infrastructure, waterway safety operations, and barge and recreational traffic.
In 2012, the U.S. Senate and House introduced new bills aimed at combating the spread of Asian carp into the Great Lakes by expediting some items of the Stop Asian Carp Act of 2011.[33] The legislation provides direction to 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.
The Water Resources Development Act of 2020 was passed by Congress to provide $25 million to efforts against the invasive species in the Tennessee and Cumberland river basins.[34]
In April 2023, a new, extensive plan was created by the Invasive Carp Regional Coordinating Committee to launch over 50 projects to combat the growing Asian carp invasion in the Great Lakes region of the Midwest. The committee is partnering with a collaboration of 26 U.S. and Canadian federal, state, provincial, tribal, regional and local agencies to work on new technologies and strategies to implement against Asian carp spreading to the Great Lakes.[35]
The 2023 Invasive Carp Action Plan includes the following: