Australia's Carp Problem

Carp (Cyprinus carpio) are an introduced pest species that dominate waterways across the Murray Darling Basin. Introduced into Victorian waterways in the 1970s, carp are native to European and Asian waterways. Carp are incredibly invasive and are now found on all continents (except Antarctica).

Major floods of 2022 resulted in massive carp breeding and migration of carp in Southeast Australia, with populations now at an all-time high of 375 million, accounting for around 90% of the entire biomass of fish in the Murray Darling basin.

Ecosystem and native fish impacts

Carp are the most ecologically damaging non-native species globally. Their vacuum style of feeding stirs up sediments from river and lake beds, increasing the turbidity of the water (the cloudiness of the water). Increased turbidity reduces sunlight’s ability to penetrate the water, reducing aquatic plant growth which provides critical food and shelter for native fish. Carp also remove established aquatic plants, causing extensive erosion of riverbanks. Carp also compete with native fish for food and prey on native fish eggs, larvae and juvenile fish.

Social and economic impacts

Studies by the NCCP estimate carp impacts cost the Australian economy $11.8 to 500 million per year. This includes ecological, social, recreational, amenity downstream impacts from degraded water quality, Infrastructure, as well as secondary impacts. These impacts are worse when carp populations are highest following in wet year breeding conditions.

National Carp Control Plan (NCCP)

In 2016, the Australian Government invested $10.37 million in the National Carp Control program (NCCP) to assess the feasibility of using the carp virus as a biocontrol agent to control Australian carp populations. The carp virus is a species-specific waterborne disease that only causes mortality in carp and koi carp. In 2022, the NCCP published its key findings which involved extensive research, international collaboration, viral testing on other species, and community consultation, making it the most comprehensive biological control assessments ever conducted in Australia. In 2024, the Federal government announced a further $3 million dollars in research funding to fill some remaining information gaps. For further information, please visit National Carp Control Plan | FRDC.

Carp virus release approvals process

The Federal government is responsible for determining if the carp virus can be used a biological control agent to reduce carp populations. In 2024, the Department of Agriculture, Forestry and Fisheries (DAFF) outlined a two phased roadmap for the Carp Biological Control Program. The outcomes of the NCCP research will be used to inform Federal legislative approvals processes under the EPBC Act 1999, Biological Control Act 1984, Biosecurity Act 2015, Water Act 2007 and Agriculture and Veterinary Chemicals Codes Act 1994. If approved for release, state jurisdictions will play a key role in implementing the release of the virus requiring further consultation and approvals processes. The timelines for deciding on the release of the carp virus are not clear at this stage.

A trial approach to releasing the carp virus

The Victorian Fisheries Authority (VFA) is leading the development of a Victorian plan to trial the use of carp virus initially within an enclosed and controlled waterway. The plan will detail the experimental design, site identification and what biosecurity controls are needed, to test the mortality rates of infected carp held under a range of carp population densities. A clearer understanding about mortality rates (currently estimates range from 30% to 80%) is needed to determine what, if any, carp cleanup operations are required if the virus is released. This initiative is recognised by the Federal Government Fisheries Ministers and the Carp Virus Trial Working Group comprising the Federal Department of Agriculture, Forestry and Fisheries (DAFF) and fisheries agencies from Queensland, New South Wales and South Australia. The project is supported by the Victorian Recreational Fishing Licence Advisory Group.

More information

Carp factsheets - a summary of key FAQs:

National Carp Control Plan - technical publications

Visit Research | FRDC to access all published NCCP papers, including:

19 Research papers,
5 planning investigations