Cane toads creep closer to Sydney after ‘concerned’ population found at Lake Macquarie

It’s not uncommon for a single cane toad to take a ride on a truck or car and hitchhike along the east coast of New South Wales, but a growing number of these wart-like, poisonous pests have made their way to private property an hour’s drive north. from Sydney – and the threat is being taken seriously by biosecurity experts.

The cane toads were found under a sheet of tin on private property in Mandalong, a suburb of southern Lake Macquarie in the Hunter region.

The NSW Department of Primary Industries (DPI) biosecurity team admits it is possible that the invasive pest may have reproduced on the property.

If true, it says the potential for “explosive” numbers during the summer months is an unwelcome but real prospect.

“We’re still beginning to understand how big this problem is and we won’t know until we have a few weeks of community reporting to see how far this population can go,” said NSW DPI biosecurity manager Quentin Hart.

The venom-seeking cane toad is widely recognized as a destructive predator that can devastate native animals and ecosystems. They can also poison pets if ingested.

A total of 17 cane toads were initially found in the building.

The NSW DPI has confirmed the discovery of two more toads in a subsequent search.

Top view of 17 deceased cane toads in order of size
The first 17 cane toads found on the Mandalong estate.(Provided: John Clulowv)

First outbreak since 2010

Mandalong is over 500 miles south of an established reed-line containment zone around the Clarence Valley on the north coast of NSW.

It is reportedly the first significant cane toad outbreak outside that buffer zone since 2010, when the amphibians took up residence at Taren Point in Sydney.

The big question is, did the toads breed on site or were they unknowingly transported as small toads, for example in garden supplies or some other item brought onto the property?

“Maybe we’re lucky, it might be limited to this very local area,” Mr Hart said.

“But we won’t really know the true situation until we can assess whether cane toads are breeding this summer.”

If the toads were to breed locally from tadpoles, it seems likely that they would be much more difficult to eradicate.

Zoomed in map of Australia with emphasis on NSW as reed toad free.  A marker near Newcastle indicates Mandalong.  at
The cane toads were found in Mandalong, 120km north of Sydney – an area considered toad free by the NSW DPI.(Supplied: NSW DPI)

Cane Toads in Australia

The cane toad is an introduced pest brought to Australia in the 1930s as part of a biological control program for beetle pests affecting the sugar cane industry.

According to naturalist John Clulow, a former associate professor at Newcastle University, they are really prolific breeders, more than rabbits.

“A decent-sized female can produce 25,000 to 35,000 eggs in one season,” he said.

“Most of those in a good breeding event would be fertilized and turn into tadpoles in a pond. So you don’t need too many.

“If one or two females succeed, then you have a real problem.”

Reed Path in Mandalong, NSW
Local Land Services employee Laurie Mullen, with one of the 17 toads found in Mandalong.(Supplied: NSWDPI)

Professor Clulow has been assisting the NSW DPI response since the toads were discovered last week, including testing tadpoles in a nearby waterway.

So far, only native frogs have been identified.

However, one of the toads in the Mandalong cluster was a fully developed male of reproductive age.

“The worrying possibility is that they are the result of a breeding event there in Mandalong,” said Professor Clulow.

“That’s the real concern here and I think that’s what DPI and biosecurity people are up to, that we might have quite a problem.”

According to Professor Clulow, numbers can be “explosive,” especially when cane toads migrate into new areas.

“Once a population moves to a new area, it can be really catastrophic for native fauna,” he said.

The NSW DPI encourages all residents in the area to look out for cane toads and report any sightings to the DPI Biosecurity Helpline at 1800 680 244.

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