Australia's Science Minister is psyched for carp-aggedon

By Megan Alpert

Carp fished out of the Murray River, New South Wales.
Carp fished out of the Murray River, New South Wales.

A strain of herpes, Australia's longest river, and millions of tonnes of dead fish.

Those are the main elements of an A$15 million project to rid the Murray River of European carp, an invasive species that has depleted native fish, muddied river waters, and caused erosion.

The plan, which scientists at Australia's Commonwealth Scientific and Industrial Research Organisation have been working on since at least 2014, is to introduce a strain of herpes into the river that only affects its carp.

The species currently makes up 80 per cent of the river basin's fish biomass, so as they die, a massive cleanup effort will be needed to rid the river of carp carcasses. The Australian Government estimates that 95 per cent of the Murray's carp will be dead within 30 years.

But what Australia's Science Minister Christopher Pyne has dubbed "carp-aggedon" could come much sooner than that: The virus, which affects the carp's skin, kidneys, and gills, effectively stops respiration, killing the fish within 24 hours of the onset of symptoms.

Pyne said past programmes introducing the virus in some Japanese lakes has resulted in 70 per cent of the carp dying within just a few weeks.

So what to do with all those dead fish?

"There's obvious talk about whether the carp could be used for fertiliser, 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 told the Australian Broadcasting Corporation.

He estimates that the dead carp mass will be between 500,000 and 2 million tonnes.

The virus will not affect the other fish in the river, and Matt Barwick, a senior fisheries manager with the Department of Primary Industries, said it also will not endanger the humans that might eat them.

However, the carp-killing initiative must be supplemented by efforts to support native fish species and promote river health, Jonathan La Nauze, healthy ecosystems programme manager for the Australian Conservation Foundation told the Guardian.

"The legacy of past mismanagement in the Murray-Darling is that 21 out of the 23 major river valleys are in poor or very poor health, according to the Sustainable Rivers Audit," La Nauze said.

Because carp are bottom-feeders, they stir up mud and sediment, turning rivers into "into muddy, soupy streams that sometimes fail to clear over a summer," according to Ken Smith, an angler who writes for Fishing World.

Pyne estimates the carp cost the Australian economy up to A$500 million annually.

- Washington Post

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