Common Carp

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.

Taxonomy

There are two or three subspecies:
Cyprinus carpio carpio (European carp). Eastern Europe (notably the Danube and Volga Rivers).
Cyprinus carpio haematopterus (Amur carp). Eastern Asia.
Cyprinus carpio rubrofuscus. Southeastern Asia. Treated as a separate species Cyprinus rubrofuscus by many authorities.
It is related to the common goldfish (Carassius auratus), with which it is capable of interbreeding.

History

The common carp is a fish native to Europe which has been introduced to every part of the world with the exception of northern Asia and the poles. The original common carp was that 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 twelfth 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.

Physiology

Wild common carp are typically slimmer than domesticated forms, with body length about four times body height (range, 3.2–4.8 times). and 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 at least 65 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 wild, non-domesticated forms tend to be much less stocky at around 20%–33% the maximum size.

Habitat

Although they are very tolerant of most conditions, common carp prefer large bodies of slow or standing water and soft, vegetative sediments. A schooling fish, they prefer to be in groups of 5 or more. They naturally live in a temperate climate in fresh or slightly brackish water with a pH of 6.5–9.0 and salinity up to about 5%, and temperatures of 3 to 35 °C. The ideal temperature is 23 to 30 °C, with spawning beginning at 17–18 °C; they will readily 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.

Diet

Common carp are omnivorous. They can eat a vegetarian diet of water plants, but prefer to scavenge the bottom for insects, crustaceans (including zooplankton), and benthic worms.

Reproduction

An egg-layer, a typical adult fish can lay 300,000 eggs in a single spawning. Although carp typically spawn in the spring, in response to rising water temperatures and rain fall, 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.

Predation

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 similar 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, goosander, and osprey) and mammals (including otter and mink).

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 world wide. 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. In Western Europe, the carp is cultured more commonly as a sport fish although there is a small market as food fish.
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.
Carp is also eaten in many parts of the world both when caught from the wild and raised in aquaculture. In Germany, Austria, the Czech Republic, Slovakia, Hungary, Croatia and Poland, carp is a traditional part of a Christmas Eve dinner.
Carp are mixed with other common fish to make gefilte fish, popular in Jewish cuisine.
The Romans farmed carp and this pond culture continued through the monasteries of Europe and to this day. In China, Korea and soon after in Japan carp farming took place as early as the Yayoi Period (ca. 300 B.C – 300 A.D.)