Introduced to Australia in the late nineteenth century, common carp have become a major freshwater pest. Thriving in disturbed habitats, they degrade waterways and compete with native fish for resources. Their mobile nature and fecundity, along with illegal human-assisted dispersal, has allowed them to colonise nearly all of the Murray-Darling river system, as well as many coastal rivers. Their broad tolerance to salinity and temperature gives them the potential to occupy possibly all permanent freshwater habitats in Australia.

This project explores the population genetics of common carp with the aim of making recommendations for control programs. Preliminary results have so far found evidence that at least two genetic strains have made a significant contribution to the carp population of the Murray-Darling Basin (MDB); there are clear patterns of colonisation, with some populations being established in discrete colonisation events; although there are high levels of geneflow between most regions, the movement of carp is limited by dams and restricted water flows; carp may be spawning predominantly in three ‘hot-spots’; and there are approximately 9-10 potential management units within the MDB. This information, when combined with demographic and modelling data, will be useful in devising control programs for this pest species.