The common carp (Cyprinus carpio) is a widespread freshwater fish of eutrophic waters in lakes and large rivers in Europe and Asia. The wild populations are considered vulnerable to extinction, but the species has also been domesticated and introduced into environments worldwide, and is often considered an invasive species. It gives its name to the carp family: Cyprinidae. It is on the List of the world's 100 worst invasive species.
The four subspecies are:
- Cyprinus carpio carpio (European carp) is found in Eastern Europe (notably the Danube and Volga Rivers).
- Cyprinus carpio yilmaz (Deniz carp) is found in Anatolia Turkey (notably around Corum) and Victoria, Australia (around Merri Creek and Coburg Lake).
- Cyprinus carpio haematopterus (Amur carp) is native to eastern Asia.
- Cyprinus carpio rubrofuscus, from Southeast Asia, is treated as a separate species Cyprinus rubrofuscus by many authorities.
The common carp is native to Asia, and has been introduced to every part of the world with the exception of the Middle East and the poles. The original common carp was found in the inland delta of the Danube River about 2000 years ago, and was torpedo-shaped and golden-yellow in colour. It had two pairs of barbels and a mesh-like scale pattern. Although this fish was initially kept as an exploited captive, it was later maintained in large, specially built ponds by the Romans in south-central Europe (verified by the discovery of common carp remains in excavated settlements in the Danube delta area). As aquaculture became a profitable branch of agriculture, efforts were made to farm the animals, and the culture systems soon included spawning and growing ponds. The common carp's native range also extends to the Black Sea, Caspian Sea and Aral Sea.
Both European and Asian subspecies have been domesticated. In Europe, domestication of carp as food fish was spread by monks between the 13th and 16th centuries. The wild forms of carp had reached the delta of the Rhine in the 12th century already, probably also with some human help. Variants that have arisen with domestication include the mirror carp, with large, mirror-like scales (linear mirror – scaleless except for a row of large scales that run along the lateral line; originating in Germany), the leather carp (virtually unscaled except near dorsal fin), and the fully scaled carp. Koi carp (錦鯉 (nishikigoi) in Japanese, 鯉魚 (pinyin: lĭ yú) in Chinese) is a domesticated ornamental variety that originated in the Niigata region of Japan in the 1820s. They also invaded the Great Lakes in 1896 when the area near Newmarket, Ontario, flooded and allowed them to escape into the Holland River.
Wild common carp are typically slimmer than domesticated forms, with body length about four times body height, red flesh, and a forward-protruding mouth. Their average growth rate by weight is about half the growth rate of domesticated carp They do not reach the lengths and weights of domesticated carp, which (range, 3.2–4.8 times) can grow to a maximum length of 120 centimetres (47 in), a maximum weight of over 40 kilograms (88 lb), and an oldest recorded age of 65 years, but reliable information seems to exist about nishikigoi of over 100 years. The largest recorded carp, caught by an angler in January 2010 at Lac de curtons (Rainbow Lake) near Bordeaux, France, weighed 42.6 kilograms (94 lb). The largest recorded weight of a domesticated carp was of a nishikigoi especially bred for size, with a length of 125 cm and a weight of 45 kg.
Although tolerant of most conditions, common carp prefer large bodies of slow or standing water and soft, vegetative sediments. As schooling fish, they prefer to be in groups of five or more. They naturally live in temperate climates in fresh or slightly brackish water with a pH of 6.5–9.0 and salinity up to about 0.5%, and temperatures of 3 to 35°C. The ideal temperature is 23 to 30°C, with spawning beginning at 17–18°C; they easily survive winter in a frozen-over pond, as long as some free water remains below the ice. Carp are able to tolerate water with very low oxygen levels, by gulping air at the surface.
An egg-layer, a typical adult female can lay 300,000 eggs in a single spawn. Although carp typically spawn in the spring, in response to rising water temperatures and rainfall, carp can spawn multiple times in a season. In commercial operations, spawning is often stimulated using a process called hypophysation, where lyophilized pituitary extract is injected into the fish. The pituitary extract contains gonadotropic hormones which stimulate gonad maturation and sex steroid production, ultimately promoting reproduction.
A single carp can lay over a million eggs in a year, yet their population remains the same, so the eggs and young perish in similarly vast numbers. Eggs and fry often fall victim to bacteria, fungi, and the vast array of tiny predators in the pond environment. Carp which survive to juvenile are preyed upon by other fish such as the northern pike and largemouth bass, and a number of birds (including cormorants, herons, goosanders, and ospreys) and mammals (including otter and mink).
Introduction into other habitats 
Common carp have been introduced, sometimes illegally, to most continents and some 59 countries. Due to their fecundity and their feeding habit of grubbing through bottom sediments for food, they are notorious for altering their environments. In feeding, they may destroy, uproot, disturb and eat submerged vegetation, causing serious damage to native duck, such as canvasbacks, and fish populations. Similar to the grass carp, the vegetation they consume is not completely digested, and rots after excretion, raising the nutritional level of the water and causing exsessive algae growth. They destroy nests of other fish and eat their eggs, reducing their numbers significantly.
Efforts to eradicate a small colony from Tasmania's Lake Crescent without using chemicals have been successful, but the long-term, expensive and intensive undertaking is an example of both the possibility and difficulty of safely removing the species once it is established. One proposal, regarded as environmentally questionable, is to control common carp by deliberate exposing them to carp-specific Koi herpes virus with its high mortality rate. In Utah Lake, the common carp's population is expected to be reduced by 75% by using nets to catch millions of them and either give them to people who will eat them or processing them into fertilizer. This, in turn, will give the native June sucker a chance to recover its declining population. Another method is by trapping them in tributaries they use to spawn with seine nets and exposing them to rotenone. This method has shown to reduce their impact within 24 hours and greatly increase the native vegetation and desirable fish species. This also leaves the baby carp easily preyed upon by native fish.
In Australia, enormous anecdotal and mounting scientific evidence indicates introduced carp are the cause of permanent turbidity and loss of submergent vegetation in the Murray-Darling river system, with severe consequences for river ecosystems, water quality and native fish species. In Victoria, Australia, common carp has been declared as noxious fish species, the quantity a fisher can take is unlimited. In South Australia, it is an offence for this species to be released back to the wild. An Australian company converts common carp into plant fertilizer.
Common carp were brought to the United States in 1831. In the late 19th century, they were distributed widely throughout the country by the government as a food-fish, but they are no longer prized as a food-fish. As in Australia, their introduction has been shown to have negative environmental consequences, and they are usually considered to be invasive species. Millions of dollars are spent annually by natural resource agencies to control common carp populations in the United States.
Common carp are believed to have been introduced into the Canadian province of British Columbia from Washington. They were first noted in the Okanagan Valley in 1912, as was their rapid growth in population. Carp are currently distributed in the lower Columbia (Arrow Lakes), lower Kootenay, Kettle (Christina Lake), and throughout the Okanagan system.
As food and sport 
Cyprinus carpio is the number one fish of aquaculture. The annual tonnage of common carp, not to mention the other cyprinids, produced in China alone exceeds the weight of all other fish, such as trout and salmon, produced by aquaculture worldwide. Roughly three million tonnes are produced annually, accounting for 14% of all farmed freshwater fish in 2002. China is by far the largest commercial producer, accounting for about 70% of carp production. Carp is eaten in many parts of the world both when caught from the wild and raised in aquaculture. In Central Europe, it is a traditional part of a Christmas Eve dinner. Many people in Poland, Germany, Czech Republic, Slovakia and Hungary buy a live carp and bring it home three or two days before Christmas Eve. It is kept one or two days in a bathtub, and then killed. Traditional Czech Christmas Eve dinner is thick soup of carp's head and offal, fried carp meat with potato salad or boiled carp in black sauce. In some Czech families, the carp is not killed, but after Christmas returned to a river or pond. Slovak Christmas Eve dinner is quite similar with soup varying according to the region and fried carp as the main dish. In Western Europe, the carp is cultured more commonly as a sport fish, although there is a small market as food fish. Carp are mixed with other common fish to make gefilte fish, popular in Jewish cuisine.
Common carp are extremely popular with anglers in many parts of Europe, and their popularity as quarry is slowly increasing among anglers in the United States (though destroyed as pests in many areas), and southern Canada. Carp are also popular with spear, bow, and fly fishermen.
The Romans farmed carp and this pond culture continued through the monasteries of Europe and to this day. In China, Korea and Japan, carp farming took place as early as the Yayoi Period (c. 300 BCE – 300 CE).
See also 
- Freyhof, J. & Kottelat, M. (2011). "Cyprinus carpio". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. Retrieved June 23, 2011.
- Fishbase: Cyprinus carpio carpio Linnaeus, 1758
- Arkive: Common carp (Cyprinus carpio)
- Jian Feng Zhou, Qing Jiang Wu, Yu Zhen Ye & Jin Gou Tong (2003). Genetic divergence between Cyprinus carpio carpio and Cyprinus carpio haematopterus as assessed by mitochondrial DNA analysis, with emphasis on origin of European domestic carp Genetica 119: 93–97
- Fishbase: Cyprinus carpio haematopterus Martens, 1876
- Fishbase: Cyprinus rubrofuscus Lacepède, 1803
- Taylor, J., R. Mahon. 1977. Hybridization of Cyprinus carpio and Carassius auratus, the first two exotic species in the lower Laurentian Great Lakes. Environmental Biology Of Fishes 1(2):205-208.
- Photo of goldfish x common carp hybrid in Melton Hill Reservoir from the Tennessee Wildlife Resources Agency
- Balon, E. K. (2004). About the oldest domesticates among fishes. Journal of Fish Biology, 65 (Supplement A): 1–27. In Carp Fishing Science
- Aanvullend Archeologisch Onderzoek op terrein 9 te Houten-Loerik, gemeente Houten (U.)
- Ray Jordan Koi History
- Wilt, R.S. de, Emmerik W.A.M. (2008-31-1). "Kennisdocument Karper Sportvisserij Nederland". Retrieved december 13,2011.
- Füllner G., Pfeifer M., Langner N. "Karpfenteichwirtschaft". Sächsische Landesanstalt für Landwirtschaft. Retrieved december 13,2011.
- "ghostcarplake.com". ghostcarplake.com. Retrieved 2011-12-03.
- Lac de curtons (in French)
- Unread prime source: Teichfischer, B.: Farbkarpfen. Urania-Verlag Leipzig, Jena, Berlin (1988): 152 S.
- FAO Fisheries & Aquaculture: Cultured Aquatic Species Information Programme – Cyprinus carpio
- "Carp Fishing for carp fishing information". Carp-fishing.org. Retrieved 2011-12-03.
- Cramp, S. (ed.). The Birds of the Western Palearctic volumes 1 (1977) & 2 (1980). OUP.
- "Welcome to". Lakeconservation.com. 2010-01-15. Retrieved 2011-12-03.
- "Echuca Moama Fishing - European Carp". Echuca.ws. Retrieved 2011-12-03.
- Victorian Recreational Fishing Guide 2006-2007
- carp as fertilizer
- [dead link]
- USGS Nonindigenous Aquatic Species Program
- Cyprinus carpio (Linnaeus) on Living Landscapes, from the Royal British Columbia Museum
- [dead link]
- [dead link]
- Daily Yomiuri newspaper, September 19, 2008
|Wikimedia Commons has media related to: Cyprinus carpio|
|Wikispecies has information related to: Cyprinus carpio|
- "Cyprinus carpio". Integrated Taxonomic Information System. Retrieved 4 October 2004.
- Froese, Rainer and Pauly, Daniel, eds. (2004). "Cyprinus carpio" in FishBase. September 2004 version.
- Cyprinus carpio Arkive