Carp-culling project will be a one-hit wonder, experts warn

The Australian government plans to slash carp fish numbers in Australia’s waterways by infecting the pest-species with a herpes virus.

But, University of Sydney experts are warning that it will be a one-hit wonder.

The warning comes as the Fisheries Research and Development corporation investigates whether to go ahead with a planned release of the virus in an effort to help rebuild native fish numbers in Australia’s waterways.

University of Sydney associate professor and National Carp Control Program Scientific Advisory Group member, Joy Becker, said the release of the virus in waterways will undoubtedly cause a single epidemic of herpesvirus disease resulting in massive deaths among carp.

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“However, there’s little evidence to suggest that we will see repeated outbreaks of a magnitude to counter the reproductive potential of the surviving carp,” she said.

This conclusion is based on a review of evidence from around the world examining the impact of the koi herpesvirus on common carp in natural and farmed environments.

Becker and her author-colleagues, Michael Ward and Paul Hick from the Sydney School of Veterinary Science explain that the likelihood of the carp population being controlled by releasing the virus is significantly reduced due to herd immunity and the carp’s “remarkable fecundity”.

They warn this means the government’s $15 million culling program, which was announced in parliament by former deputy prime minister Barnaby Joyce, could be successful just once.

The research team said their great concern is how quickly the virus reaches balance in host populations, which occurred within two years in a study in Japan.

In some areas of Australia’s largest river catchment – the Murray-Darling Basin – carp are reported to dominate fish communities, comprising 80 to 90 per cent of the biomass.

Common carp are an introduced species in Australia.