Environment

Release virus to rid Australia of carp, fishers, farmers and environmentalists declare

A virus that kills carp should be used to help rid Australian rivers of the destructive feral fish species, a unique coalition of anglers, farmers and conservationists have declared.

Some of the nation's biggest fishing, farming and green groups say governments now have a once in a generation opportunity to use "biological controls" for carp, and they should commit funds to that end.

Carp circle in Sullivans Creek at the Australian National University. The presence of carp is a major cause of the ...
Carp circle in Sullivans Creek at the Australian National University. The presence of carp is a major cause of the decline in native fish numbers. Photo: Danswell Starrs

Carp, an introduced species, is the bane of many fishermen and their presence is a major cause of the decline in native fish numbers in numerous freshwater ecosystems, in particular the Murray-Darling Basin.

By feeding on river bottoms, carp cloud water, harming native fish's ability to breed and feed and reducing river plant growth. Carp can also feed on young fish and compete with native species for habitat.

In recent years hopes have been raised that Australian carp numbers could be dramatically reduced by introducing a virus that originally emerged in Europe in the 1990s.

Allan Hansard, who heads the Australian Recreational Fishing Foundation, said if the virus was effective, inland waterways could be returned to conditions close to what they were before carp were brought to Australia.

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"People say inland waterways like the Murray-Darling used to be clear, wouldn't it be great to see that," Mr Hansard said.

The groups behind the push include the fishing foundation, the Australian Conservation Foundation, National Farmers' Federation, Invasive  Species Council and the National Irrigators' Council.

CSIRO has been studying the virus – called Koi herpesvirus – at laboratories near Geelong since 2007. The head of the project at CSIRO, Dr Ken McColl, said it could kill up to 70 to 90 per cent of carp.

CSIRO has been testing to see whether releasing the virus would pose any threat to Australian fish species. So far the research had shown no ill effects, Dr McColl said.

Carp are now the most abundant large freshwater fish in some areas, including most of the Murray-Darling Basin.

Carp are now the most abundant large freshwater fish in some areas, including most of the Murray-Darling Basin. Photo: Department of Primary Industries, NSW

Testing had also occurred on invertebrates, mammals and birds. Dr McColl said that in Europe, the virus had never spread to other species or humans.

Dr McColl said final testing was being completed this year on two fish types and, assuming that went well, he believed the virus would not pose risks to humans and other species if its release was given the go-ahead.

"It's potentially a white knight for removing, or at least reducing carp numbers significantly in the Murray-Darling Basin," Dr McColl said.

Acting campaigns director at the Australia Conservation Foundation, Jonathan La Nauze, told Fairfax Media any government hesitancy to back the use the carp virus might be about the potential clean-up effort it would require.

He said the sheer numbers of carp in Australian rivers – in the Murray-Darling carp makes up over 80 per cent of fish biomass – meant the virus could result in millions of tonnes of dead fish that need to be removed.

In the statement the groups say community engagement and clean-up efforts would need to accompany the virus' release. 

A spokesman for Environment Minister Greg Hunt said any proposals to help eradicate carp would be considered "exclusively on the basis of science, and against the most rigorous standards".