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Release herpes virus to kill invasive carp in Australia, groups urge

  • A coalition of conservationists, recreational fishers and farmers want Australia’s state and federal governments to get rid of European carp, or “Australia’s worst freshwater pest”, by releasing carp-specific herpes virus in Murray river.
  • Scientists have shown that the koi herpesvirus, also called Cyprinid herpesvirus 3 (or CyHV-3), can be used as an effective biocontrol against the invasive carps.
  • The scientists have also found that the virus doesn’t affect native Australian or important introduced species of fish, or other groups of animals including humans.

A coalition of conservationists, recreational fishers and farmers want Australia’s state and federal governments to get rid of European carp, or “Australia’s worst freshwater pest”, from Murray river, according to a media statement by Australian Conservation Foundation.

Concerned about the threat that the invasive carps pose to native Australian fish biodiversity, five groups — the Australian Conservation Foundation (ACF), the Australian Recreational Fishing Foundation, the Invasive Species Council, the National Farmers’ Federation and the National Irrigators Council — have come together to support the release of carp-specific herpes virus in the Murray Darling Basin. The virus is known to kill only carps without affecting native fish species.

“We are united in calling for clearer, healthier waterways and fish communities,” Jonathan La Nauze, acting campaigns director for the ACF, said in the statement. “Australia now has a once in a generation opportunity to achieve this through broad-scale biological control using a naturally occurring virus that is specific to Common carp.”

European carp is a large freshwater fish found in rivers of Europe and Asia. It first became a threat to Australia’s native fish biodiversity in the 1960s, after a carp accidentally made its way from an Australian fish farm to a river system.

The fish “multiplied like rabbits”, Ken McKoll of Commonwealth Scientific and Industrial Research Organisation (CSIRO) writes, and quickly became one of Australia’s most damaging pests. Carps now make up more than 90 percent of the fish biomass in many parts of the Murray Darling Basin, he adds, and have wiped out much of the river’s native fish biodiversity.

A coalition of recreational fishers and conservationists are urging Australia’s government to release koi herpesvirus to control populations of the invasive common carp in Australia’s Murray river. Photo by Viridiflavus , Wikimedia Commons CC By SA 3.0

Over seven years of research, scientists at CSIRO and the Invasive Animals-Cooperative Research Centre (CRC) have shown that the koi herpesvirus — also called Cyprinid herpesvirus 3 (or CyHV-3) — can be used as an effective biocontrol against the invasive carps.

“Testing of CyHV-3 in the high-security Fish Diseases Laboratory at our Australian Animal Health Laboratory (AAHL), in Geelong, Victoria, has proven that the same virus does in fact kill Australian carp, and it kills them fast,” McKoll writes. The virus affects the carp’s skin and kidneys, killing them in just over a week.

On the other hand, the virus doesn’t seem to affect native Australian or important introduced species of fish, the scientists have found.

“It has been shown to pose no danger to 13 native species such as Murray cod, various species of perch, eel and catfish, as well as a crustacean (yabbies) and a non-native fish species, the rainbow trout,” McColl writes.

The scientists, including McColl, have also tested the virus on other groups of animals, such as birds, mammals, amphibians and reptiles, and found no effect on them.

“Virtually every species have their own specific herpes virus and very few of those viruses cross into other species,” McColl told the Guardian.

The virus is also safe for people, the scientists say.

“CyHV-3 has devastated carp farming around the world yet despite the large numbers of people working on these affected farms, there has been no evidence of any effect of the virus on them,” McColl writes. “We have also exposed mice to CyHV-3, and found no evidence of disease. Mice were chosen as being a representative mammal, just like a human. And finally, a report to the European Commission by the Scientific Committee on Animal Health and Animal Welfare stated that there is no evidence for ANY fish virus causing disease in humans.”