Carp (Cyprinus carpio)

About Cyprinus carpio

Carp are a large freshwater fish native to central Asia. Carp are very versatile, and can live in a great variety of habitats including highly degraded areas. Over the past few decades carp have spread across most of south-eastern Australia. They are now the most abundant large freshwater fish in some areas, including most of the Murray-Darling Basin, and are thought to have contributed to the degradation of our natural aquatic ecosystems.

Habitat: Carp are usually found in still or slowly flowing waters at low altitudes, especially in areas where there is abundant aquatic vegetation. They are also found in brackish lower reaches of some rivers and coastal lakes.

They are capable of tolerating a range of environmental conditions. They have a greater tolerance of low oxygen levels, pollutants and turbidity than most native fish, and are often associated with degraded habitats, including stagnant waters.

Changes to water flows, declining water quality and other changes to river habitats over the past few decades have negatively affected many native fish while favouring carp.

Reproduction: Under suitable conditions, carp are highly prolific. They mature early – as early as 1 year for males and 2 years for females – and the females produce large numbers of sticky eggs (up to 1.5 million for a 6kg fish).

Carp migrate to and from breeding grounds during the breeding season, sometimes travelling hundreds of kilometres.

Most eggs and larvae die before they reach adulthood, although more may survive if environmental conditions are suitable. Floods seem to provide especially favourable conditions for carp breeding as well as abundant food for juveniles.

Water Requirements

Introduced European carp (C. carpio) spawn in vegetated floodplain wetlands following inundation when water temp is > 16 ^oC. C. carpio recruits can return to the main stream channel if the floodplain wetlands become reconnected after a spawning event but before the drying of the wetland.

This model uses a flow or depth time series along with a user defined overbank threshold to identify floodplain inundation events. Those inundation events provide adult C. carpio with an opportunity to move from main river channels onto floodplains and spawn. The floodplain wetlands are considered to be filled if an inundation event occurs. If the temperature is suitable when the wetland fills (or at some subsequent time when the wetland still has water) then C. carpio are considered to spawn. C.Carpio recruits are considered to be mature enough to return to the main channel after a user defined period from the commencement of spawning (default 30 days). Hence if a floodplain inundation event occurs when conditions are suitable for viable recruits then the model output records each day when recruitment of C.carpio from the wetlands to the main channel is possible.