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- Oct 28, 2017
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ABC Tropical North
By Ollie Wykeham
October 1. 2020.
A female elseya Irwini, commonly known as Irwin's turtle after Steve and Bob Irwin, who recorded the species in 1990.(Supplied: Jeff Tan)
A turtle named after famed naturalist Steve Irwin that has the ability to breathe through its bum may be under threat from the proposed $4 billion Urannah Dam.
- Irwin's turtle was first photographed by Steve and Bob Irwin in 1990
- The turtle can breath underwater through its cloaca, which makes it sensitive to changes in water conditions
- A scientist studying the turtle says the planned Urannah Dam site is the only known habitat for the turtle
The turtle's known habitat is limited to a 25-kilometre stretch of the Bowen River inland from Mackay.
James Cook University doctorate candidate Jason Schraffer said he was concerned about a significant risk to the isolated population of Irwin's turtles.
"The only known study population is smack bang on the site of the proposed dam," he said.
"It's not just the Urannah Dam, which is right on the best population of these turtles that we know of, it's also the cumulation of all the other dams that exist or are proposed on the catchment."
Research over 20 years showed turtles like the Irwin's were more prone to population decline due to dams, said Mr Schraffer.
Wiri Traditional Owner Kenny Dodd holding a female Irwin's turtle on Urannah Creek.(Supplied: Jeff Tan)
The animal is part of a rare group of turtles species able to breath underwater through their cloacae, cavities also used as anal, urinary and birthing canals in reptiles, birds and monotremes including platypuses.
"It's a specialised species that is capable of aquatic respiration," said Mr Schraffer.
"It does that through specialised organs in its cloaca.
"They are able to take the oxygen directly out of the water through the massive amounts of folds in the organs which they pump like lungs.
"So they are always in contact with the water, which makes them vulnerable to poor water quality."
Another cloacal-breathing turtle, the Mary River turtle, was one of the species cited as a reason for revoking environmental approvals for the controversial Traveston Crossing dam in south-east Queensland.
Flying to 'really remote' creek
The Irwin's turtle was put forward for listing as a threatened species in 2009, but that was rejected due to a lack of information on population numbers and distribution.
A new study, led by Dr Cecillia Villacorta Rath, is hoping to fix that gap in knowledge by testing waters in the catchment for environmental DNA.
Dr Villacorta Rath said eDNA was a better survey tool than trapping because the sampling process was faster and the technique could cover larger and more remote areas.
"The Urannah Creek is really remote, so if you want to do traditional surveys snorkelling or setting nets, it would take you days," she said.
A stretch of the Broken River, near Urannah Creek, where a 1.5 megalitre dam is planned.(Supplied: Jeff Tan)
"Whereas I am intending to hire a helicopter, fly to the test sites, get off, sample the water and come back.
"So I can cover a huge area in one or two days. I can cover 14 sites alone."
She said sample sites would include areas that had a historical record of the turtles, but no sighting in years, including some sites near the Budekin Falls dam where there had been no sightings since it was built.
"We want to . . . see if there are turtles present," she said.
But she said the testing would not provide evidence of the dam's impact.
"Other types of development could have impacted the turtle, but I can only give certain information if the turtle is present there now or not.
"We could link it back to the dam, but it's not direct cause and effect.
"I'm just hoping I will be able to advance the knowledge of the current species distribution and I hope the information will be helpful to those who need to make decisions on the dam development."
Irwin's turtle is distinctive because it can breath under water by pumping oxygenated water in and out of it's cloaca.(Supplied: Jeff Tan)
The State Government said the Urannah Project had been declared a coordinated project requiring an environmental impact statement (EIS).
The Coordinator-General is drafting terms of reference for what the EIS must address and will take advice from the Department of Environment and Science on state-listed flora and fauna.
Similarly, the Commonwealth Department of Agriculture, Water and the Environment specifies what the terms of reference must include, regarding federally listed species.
The draft terms of reference will be released for public comment on what the EIS should address, to be considered by the Coordinator-General.