Plants and Animals Index

European Carp

Scientific Name Cyprinus carpio Linnaeus Other common names European carp, Common carp, Koi carp

Photographer - Gunther Schmida © Murray Darling Basin Commission

Identification  

A medium sized fish with a forked tail. Maximum 1200 mm and 60 kg; usually up to 4–5 kg. The mouth is of moderate size, with thick fleshy lips and two pairs of barbels (‘whiskers’) at the corners. The single long, low dorsal fin has a stout serrated spine at the front. The scales are large and thick. Some individuals are only partly scaled, with very large scales in three or four rows (‘mirror carp’), and some have no scales (‘leather carp’). The back is usually olive-green, silvery-grey or brownish and the belly a creamy or silvery-yellow.

Biology and Habitat

The Carp is usually associated with warm, slow-flowing lowland rivers or lakes, and is rarely found in clear, cool fast-flowing streams. It is tolerant of a wide range of environmental conditions and able to survive extremely low levels of dissolved oxygen. When Carp are seen apparently gasping at the water surface, they are not taking in oxygen, but rather feeding on zooplankton. Males are sexually mature at 2–3 years (300 mm) and females at 3–4 years (350 mm). Spawning usually occurs in spring and summer when water temperatures are 17–25°C. Spawning fish congregate in shallow water with egg-laying often accompanied by much chasing and splashing as fish break the water surface with their back and tail. Eggs are adhesive and laid in clumps on freshwater vegetation, logs and submerged grass. They are 0.5 mm in diameter and hatch in 2–6 days, depending on water temperature. Large wetland areas such as the Barmah-Millewa Forest and the Gwydir wetlands are thought to be significant ‘hotspots’ for Carp breeding. Carp feed by ‘mumbling’ in the sediment on the bottom or banks of water bodies. This involves sucking in sediment, sorting the edible items from the inedible sediment, and expelling the sediment through the gill openings. Dietary items include zooplankton, freshwater insect larvae, crustaceans, molluscs and to a lesser extent plant material. Carp carry the parasitic copepod Anchorworm (Lernaea sp.), which infests a range of native and alien fish species.

Impacts on Native Fish

The impacts of Carp are not clear but their feeding behaviour has led to considerable concern that they may be increasing turbidity levels in waterways and undermining riverbanks. They may also be altering zooplankton levels, exacerbating algal blooms, and their high abundance in many streams and lakes indicates they are probably competing with native fish for food and space.

Distribution and Abundance

Carp are native to central Asia. They were first introduced into Australia in the mid 1800s, but remained in two relatively confined locations, Sydney and the Murrumbidgee Irrigation Area. These two populations were different strains of the one species and showed no signs of spreading. In the early 1960s, a fish farmer illegally introduced a new strain, Boolarra, and it has rapidly colonised watercourses throughout Australia. A recent genetic study of Carp in Australia has identified a fourth strain. Koi, which is present in the wild in the ACT and Tas. The feral Koi strain lacks the bright orange, black or white colouration seen in aquarium Koi. Carp are present in the majority of slopes and lowland rivers and creeks, and in upland streams as well. They often comprise between 70 and 90% of the fish biomass in lakes and streams.

General References

Brown, P., Sivakumaran, K.P., Stoessel, D. and Giles, A. 2005. Population biology of carp (Cyprinnus carpio L.) in the mid-Murray River and Barmah Forest Wetland, Australia. Marine and Freshwater Research 56: 1151–1164.

Brumley, A.R. 1996. Family Cyprinidae: carps, minnows, etc. Pp. 99–106 in: McDowall, R.M. (ed.) Freshwater Fishes of South-eastern Australia. Reed Books. Second edition. Sydney.

Crook, D.A. 2004. Is the home range concept compatible with the movements of two species of lowland river fish? Journal of Animal Ecology 73: 353–366.

Davis, K.M., Dixon, P.I. and Harris, J.H. 1998. Allozyme and mitochondrial DNA analysis of carp, Cyprinus carpio L., from south-eastern Australia. Marine and Freshwater Research 50 (3): 243–260.

Driver, P.D., Harris, J.H., Closs, G.P. and Koen, T.B. 2005. Effects of flow regulation on carp (Cyprinus carpio L.) recruitment in the Murray-Darling Basin, Australia. River Research and Applications 21: 327–335.

Harris, J.H. and Gehrke, P.C. (eds) 1997. Fish and Rivers in Stress: The NSW Rivers Survey. New South Wales Fisheries and the Cooperative Research Centre for Freshwater Ecology.

Koehn, J.D. 2004. Carp (Cyprinus carpio) as a powerful invader in Australian waterways. Freshwater Biology 49: 882–894.

Koehn, J.D., Gehrke, P.C. and Brumley, A.R. 2000. Managing the Impacts of Carp. Bureau of Rural Sciences, Canberra.

Nicol, S.J., Lieschke, J.A., Lyon. J.P. and Koehn, J.D. 2004. Observations on the distribution and abundance of carp and native fish, and their response to a habitat restoration trial in the Murray River, Australia. New Zealand Journal of Marine and Freshwater Research 38: 541–551.

Stuart, I. and Jones, M. 2002. Ecology and Management of Common Carp in the Barmah-Millewa Forest. Final report to Agriculture, Fisheries and Forestry Australia. Arthur Rylah Institute for Environmental Research, Victoria.

Stuart, I.G. and Jones, M. 2006. Large, regulated forest floodplain is an ideal recruitment