Australia plans to cull its river carps by giving them herpes virus

Australia, which has a serious problem with carps that have been infesting its rivers, now plans to cull the population of these feral pests by spreading the herpes virus into the waters. The government has announced that it will allocate AU$15m ($11.4m/£7.8m) in the federal budget for the eradication of the problem fish as part of what Science Minister Christopher Pyne reportedly called a "carp-aggedon". This will include the release of a carp-specific herpes virus into the Murray-Darling basin.

According to the Guardian, Scientists from the Commonwealth Scientific and Industrial Research Organization (CSIRO) have confirmed that the CyHV-3, which they have been testing for the past seven years, will not have a negative impact on the ecosystem and will only target the carps. The herpes strain has been tested on Australia's other native fish as well as a number of chicken, mice, frogs and turtles without showing any effect.

"The common carp is a nasty pest in our waterways and makes up 80% of fish biomass in the Murray Darling Basin," Pyne said.

"Anyone who loves the Murray knows what damage the carp have caused to the river environment over many years. The Invasive Animals Cooperative Research Centre and the CSIRO have made significant progress evaluating a viral biological control agent, we know that it works, we know it's completely safe, now we need to plan the best way to roll it out."

The virus will wreak havoc on carps, attacking their skin and kidneys after a period of seven days from administering. "It causes high death rates in common carp and in the ornamental koi carp. No other species of fish, including goldfish, are known to be affected by the virus," the CSIRO official website said.

Until now, a number of other measures have been taken to reduce the carp population, including trapping, commercial fishing and exclusion, but none of these have had the desired effect despite high costs.

The government plans to kick-start the carp control programme in 2018 with the aim of killing 95% of the population over the next 30 years. Most of the budget will go towards cleaning up the water bodies once the fish start dying. "There's obvious talk about whether the carp could be used for fertilizer, whether they could be used for pet food, whether they'll need to be buried in large graves and be allowed to dissipate back into the system," Pyne explained.

Why is carp killing required?

Carps have overpopulated the rivers in Australia causing serious harm to the country's native wildlife with the government estimating their economic impact being close to AU$500mn ($380mn/£260mn) per year.

Since their numbers are greater, the carp ends up consuming food sources of other fish as well, causing many species to come close to extinction.

Australian Conservation Foundation's healthy ecosystems programme manager, Jonathan La Nauze explained: "Carp thrive in this kind of degraded environment – in fact they make it worse by turning over the river bed, eroding the banks and literally muddying the water.

"Controlling carp must go hand-in-hand with rehabilitating riverbanks, making irrigation infrastructure fish-friendly and, of course, the release of environmental flows."