Rabbit plague looms amid calls for new biocontrols

Jun 24, 2025

Feral rabbits are one of the most destructive invasive pest species in Australia.

Although a far cry from the estimated 10 billion rabbits that infested Australia a century ago, some 200 million currently inhabit the continent and their numbers are again threatening to explode.

It has been almost a decade since the CSIRO’s last rabbit biocontrol virus release and environmental groups say it is time to fund a new one, an initiative that would require at least $15 million across five years.

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In a co-signed letter to MPs, the Invasive Species Council, Rabbit-Free Australia and the Centre for Invasive Species Solutions have urged the Federal Government to fund a nationally endorsed pipeline strategy before it’s too late.

Previous virus releases, such as myxomatosis and calicivirus, have been game-changing, but a new virus is needed every 10 years to stay effective as rabbits build immunity.

While shooting, burrow-blasting and fence-proofing were used with limited success in earlier times, it wasn’t until the mid-20th century introduction of ‘myxo’ that some measure of control over rabbit numbers was achieved.

Their estimated population of 600 million was reduced to a mere 100 million but it was back up to 300 million by the 1990s.

Variants of the calicivirus have since been used to keep numbers in check — until now.

“Rabbits are already numbering more than 200 million and with a few years of excellent seasonal conditions and no new virus on the horizon, we could be seeing a rabbit plague in the years ahead,” Rabbit-Free Australia chair Craig Magnussen said.

“The last calicivirus strain was released in 2017 and growing resistance in rabbits means population numbers are rising — and fast.”

Some money for gene drive technology in the recent federal budget was welcome but the research was at least a further two decades away from having an impact, Invasive Species Council chief executive officer Jack Gough said.

“We can’t rely on this,” he said.

“Restarting funding for research into new rabbit bio-controls should be a national priority regardless of who won the election.”

Feral rabbits outcompete and destroy the homes of native fauna, devastate threatened native plants and erode landscapes.

According to Centre for Invasive Species Solutions chair Bruce Christie, they threaten some 322 native species and cost agriculture more than $200 million annually.

“We have the science, we have the plan, but without federal investment, we can’t move forward,” he said.

The groups’ letter stresses time is of the essence.

“Without urgent investment ... impacts will rapidly intensify, reversing decades of progress and increasing the cost of control efforts for landholders, governments and communities alike,” it says.

– with AAP