Common carp are native to Europe but have been widely introduced and are now found worldwide except for the poles and northern Asia.
Carp exploit large and small man made and natural reservoirs, and pools in slow or fast moving streams. They prefer larger, slower-moving bodies of water with soft sediments but they are tolerant and hardy fish that thrive in a wide variety of aquatic habitats.
Carp often grow 30 to 60 cm in length and weigh 0.5 to 4 kg (Tomelleri and Eberle 1990); it is not uncommon for common carp to reach 15 to 20 kg (McCrimmon 1968). Males are usually distinguished from females by the larger ventral fin. Carp are characterized by their deep body and serrated dorsal spine (Nelson 1984). The mouth is terminal on the adult and subterminal on the young (Page and Burr 1991). Color and proportions are extremely variable, but scales are always large and thick. Three sub-species with slightly different scale patterns are recognized. C. carpio communis (scale carp) has regular concentric scales, C. carpio specularis (mirror carp) large scales running along the side of the body in several rows with the rest of the body naked, and C. carpio coiaceus (leather carp) with few or no scales on the back and a thick skin.
Carp generally spawn in the spring and early summer depending upon the climate. They segregate into groups in the shallows to spawn. Carp prefer shallow waters with dense macrophyte cover. Males externally fertilize eggs, which the females scatter over macrophytes in a very active manner. The eggs stick to the substrate upon which they are scattered. A typical female (about 45 cm) may produce 300,000 eggs, with some estimates as high as one million over the breeding season. Incubation is related to water temperature and has been documented at three days at temperatures of 25 to 32C. Fry average 5 to 5.5 mm in total length. Temperature, stocking density, and availability of food influence individual growth. By the time the fish reach 8 mm the yolk has disappeared and they begin to actively feed. Males typically become sexually mature at 3 to 5 years and females at 4 to 5 years.
Females facilitate attachment of fertilized eggs to the substrate. There is no further parental care.
