Cane toad discovery in Sydney reignites mass migration concerns

The toxic pest was found in a south Sydney suburb with the council now on high alert.

A cane toad sighting in southern Sydney last week has reignited alarm over their eventual mass migration further south, with the toxic amphibians already proving problematic throughout the northern states.

The invasive pest, an introduced species, has wreaked havoc in communities across Queensland, but also in the Northern Territory and northern NSW. They have contributed to the decline and extinction of several native species because of their poison.

Last Thursday, a single cane toad was sighted by a council worker mowing the lawn at a sporting oval in Miranda. A Sutherland Shire Council spokesperson told Yahoo News Australia council it is not aware of any others at this stage but is "actively patrolling and monitoring the area".

Council worker wearing green and yellow glove holding toxic cane toad.
A cane toad was found by a council worker at a sporting over in Miranda in Sydney's south. Source: Sutherland Shire Bushcare

"Council requests that the community remain vigilant and report any suspected cane toad sightings to Council's Invasive Species team promptly for investigation and collection," the spokesperson said.

"It is important not to harm a suspected cane toad, as other species, including endangered frogs and toads, can be mistaken for cane toads.

"Council remains committed to managing and mitigating the risk of cane toads in Sutherland Shire and appreciates the community's cooperation in reporting any sightings promptly."

Cane toads can 'hitch-hike' around Australia

It's not known how the cane toad appeared in Sydney, however, it's not an isolated incident. Professor Rick Shine, a cane toad expert, told Yahoo "dozens turn up in Sydney every year". In the Sutherland Shire, three cane toads were found in Caringbah in 2021. Prior to that, the last sighting was in 2014. Meanwhile, in May last year, another was found in Kenthurst in the Hills district in Sydney's north.

Thousands of cane toads covering Gold Coast street.
Cane toads swamped a Gold Coast complex recently, with residents baffled by the explosion in numbers. Source: Supplied

Shine, who's associated with Macquarie University, said that "cane toads are excellent hitch-hikers" so that's likely how it travelled so far south.

"They frequently hide in materials such as landscape and garden supplies — even in boots — and find their way to places far outside the main invaded range," he said.

Warmer weather pushing dangerous species south

Warmer temperatures south of the Queensland border are believed to have contributed to the spread of the pests — just one of several dangerous species expected to march south with hotter weather.

Highly venomous species like box jellyfish may call beaches across Newcastle, Sydney and even Wollongong home as water temperatures continue to rise. Fire ants are another pest species continuing to spread across Australia.

"Climate change will have complex effects on the toad’s ability to function in new areas," Shine said. "But there’s no doubt that unusually hot summers over recent years have aided the toad’s spread, and have helped them to survive and breed in Sydney."

A map details where cane toads have been seen in Australia. Source: Esri (esri)
A map highlights where cane toads have been seen in Australia. Source: Esri (esri)

Breeding can be problematic in new areas

A cane toad on its own is not always a cause for concern, Shine said. "It wanders around looking for company but eventually has a celibate life and dies a lonely death," he said. They're extremely problematic however if they get the chance to breed.

One female can lay between 8000 and 35,000 eggs in one sitting, so the species can quickly become established in new areas. In Sydney, Shine said there have been a few cases where they've "bred successfully" — but were ultimately maintained. "So we need to keep vigilant and eradicate any newly-founded colony before it can grow too large," he added.

People are encouraged to contact the Invasive Species Council with any suspected cane toad sightings and are warned not to kill or touch them.

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