Eight Asian carps have been substantially introduced outside of their native ranges:
All the above except largescale silver carp have been cultivated in aquaculture in China for over 1,000 years. Largescale silver carp, a more southern species, is native to, and is cultivated in Vietnam. Grass, silver, bighead and black carps are known as the "Four Domesticated Fish" in China and are the most important freshwater fish species for food and Chinese medicine. Bighead and silver carps are the most important fish, worldwide, in terms of total aquaculture production . Common carp and crucian carp are also common foodfishes in China and elsewhere. Goldfish, on the other hand, are cultivated mainly as pet fish.
Because of their prominence, and because they were imported to the United States much later than the other species, the term "Asian carps" is often used in the United States with the intended meaning of only grass, black, silver, and bighead carps. In the United States Asian carps are considered to be nuisance invasive species. Of the Asian carps that have been introduced to the United States, only two (crucian and black carps) are not known to be firmly established. Crucian carp is probably extirpated. However, since 2003, several adult, fertile, black carp have been captured from the Atchafalaya and other rivers connected to the Mississippi River. Dr. Leo Nico, in the book Black Carp: Biological Synopsis and Risk Assessment of an Introduced Fish, writes that the black carp are likely established in the USA.
Bighead, silver, and grass carps are known to be well-established in the Mississippi River basin (including tributaries) of the United States, where they at times reach extremely high abundances, especially in the case of the bighead and silver carps. 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.
These fishes are thought to be highly detrimental to the environment in the USA where they are established. 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 carps (referring to bighead, silver, black and grass carp). The plan was accepted by the National Aquatic Nuisance Species Task Force in the fall of 2007.'' In July, 2007, all silver carp and largescale silver carp were declared by the U.S. Department of the Interior to be invasive species under the Lacey Act.
The common carp was brought to the U.S. in 1831, and has been widespread for a long time. In the late 1800s they were distributed widely throughout the United States by the government as a foodfish. However, common carp are not now normally prized as a foodfish in the United States. They are often known to uproot vegetation and muddy water through their habit of rooting in the mud for food. They are thought to often have detrimental effects on native species. However, common carp are prized in Europe as a sportfish, and angling for common carp is enjoying increased popularity in the United States.
There has been a dramatic rise in the populations of bighead and silver carps where they are established in the Mississippi River basin. Bighead and silver carps 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 Canada, the federal Department of Fisheries and Oceans has evaluated the risk of Asian carps invading Canadian waters, particularly the Great Lakes, either by introduction from the Mississippi or through the market in live carps. A few bighead carp and grass carp have been captured in Canada's portions of the Great Lakes, but no Asian carp is known to be established in Canada at this time. 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 carps are known to have been introduced.
The U.S. EPA is also concerned about the possibility of Asian carp's migrating to the Great Lakes. In 2002, the U.S. Army Corps of Engineers completed an electric fish barrier in the Chicago Sanitary and Ship Canal, the only aquatic link between the Great Lakes and the Mississippi River drainage basins. The initial fish barrier was used as a demonstration project to study the design's effectiveness. Following positive results, construction began on a second, permanent barrier in 2004.
Silver carp have become notorious for being easily frightened by boats and personal watercraft, which causes them to leap high into the air. The fish can jump 8–10 feet (2.5–3 m) into the air, and numerous boaters have been injured by collisions with the fish. According to the EPA, "reported injuries include cuts from fins, black eyes, broken bones, back injuries, and concussions." Silver carp can grow to 40 pounds (18 kg) in mass. This behavior has sometimes also been attributed to the very similar bighead carp, but this is apocryphal information. Bighead carp do not normally jump when frightened. (See Kolar et al. 2007, Bigheaded carps: A Biological Synopsis and Risk Assessment.)
There is a long tradition of carps in Chinese culture and literature. A popular lyric circulating as early as two thousand years ago in the late Han period includes an anecdote which relates how a man far away from home sent back to his wife a pair of carp (Liyu), in which when the wife opened the fish to cook was found a silk strip that carried a love note of just two lines: “Eat well to keep fit” (first line) and “Missing you and forget me not” (second line).
The fish's jumping feature is set in such a proverbial idiom as "Liyu (Carp) jumps over the Dragon Gate," an idiom that conveys a vivid image symbolizing a sudden uplifting in one's social status, as when one ascends into the upper society or has found favor with the royal or a noble family through success in civil examination or through marriage. This symbolic image, as well as the image of carp itself, has been one of the most popular themes in Chinese paintings, especially those of popular styles. The fish is usually colored in gold or pink color, shimmering with an unmistakably auspicious tone. One of the well-known scenic spots in Hangchow is a big fish pond which has been alive with hundreds of carps of various colors. A three-character inscription, “Yu-Le-Guo” meaning Fish’s paradise, set above one end of the pond is the calligraphy of a famous gentry-scholar of the late Ming Dynasty named Dong Qichang. Many tourists feed the fish with bread crumbs for fun.
Among the various kinds of carp, the bighead carp is least expensive in China. The grass carp is still a main delicacy in Hangchow cuisine. Restaurants along the West Lake of the city keep the fish in cages placed under the lake water right in front of the restaurant and on an order from a customer will dash a live fish on the pavement to kill it before cooking. The fish is normally served with a sour-sweet sauce.