Wildlife experts are investigating a report of a three-metre crocodile being spotted near a popular tourist site on an island off the coast of Brisbane.
Queensland Parks and Wildlife Service rangers are installing crocodile warning signs and searching the area with drones after the sighting at Myora Springs on North Stradbroke Island, also known as Minjerribah.
Mark Jones, a traditional owner and owner of Straddie Adventures, reported the sighting of the crocodile while hosting a kayak tour with nine people on Wednesday morning, the Courier Mail reported.
Jones told the paper he was shocked and had never seen or heard of a crocodile on the island before.
“I was sitting there in the kayak where I do a talk … I thought it was a log to start with,” he said.
“It went under … then it came back up, about 10m to 15m away. I was spinning.”
Rangers from the Quandamooka Yoolooburrabee Aboriginal Corporation received the report but the state’s environment department stressed the sighting remained unconfirmed.
A department spokesperson urged visitors and residents to stay away from Myora Springs for safety reasons, and to allow rangers to complete their investigation.
“The investigation will identify if a crocodile is present on Minjerribah,” they said.
“Any crocodile confirmed to be present on Minjerribah, regardless of size, [will be] targeted for removal from the wild.”
The department said the sighting was “extremely unusual” and Minjerribah was not considered to be “typical crocodile habitat”.
Bond University marine scientist Dr Daryl McPhee said if the animal was found it would be “exceptionally rare” and a “one-in-100-year event”.
“The person who reported it, I think, is highly credible. He’s a local traditional owner but also somebody who’s spent a lot of time on the water, so I certainly put some credibility in what he’s seen,” he said.
“It is feasible, but obviously exceptionally rare for a crocodile to be this far south.”
McPhee, who authored the book the Environmental History and Ecology of Moreton Bay, said a crocodile was shot dead on the Logan River in 1905, but was rumoured to be a released pet.
He said this one could have been released although it was unlikely, or it could have drifted from the most southerly known range of crocodiles in Hervey Bay.
Crocodiles can move large distances at sea, he added, particularly after flood events.
He also wondered how long a crocodile could have been at Minjerribah before it was spotted and what a large three-metre animal could feed on in the area.
“So certainly any dogs in the area might have been at risk,” McPhee said.
“That’s something we need to think more about, assuming that it is verified as a crocodile,” he said.
Crocodiles aren’t known to frequent such southerly climates, with “croc country” beginning at the Boyne River south of Gladstone and extending northward, up the east coast and across far-north Queensland.
Prof Craig Franklin of the University of Queensland has said crocodiles can move 60km in a day.
“They move from river system to river system. They can sit underwater for more than six hours and remain hidden,” Franklin told Guardian Australia last year.