A bum-breathing freshwater turtle has conquered water turbidity and crocodiles to re-surface in the Lower Burdekin River for the first time in more than 20 years.
The Elseya irwini or Irwin's turtle first came to the attention of scientists in the 1990s when it was caught in the Lower Burdekin River.
The species was named after naturalist Bob Irwin — Steve Irwin's father — who made the discovery.
James Cook University researchers thought the species would not survive environmental conditions in the area.
The university's Tropical Water and Aquatic Ecosystem Research (TropWATER) study, led by researcher Cecilia Villacorta Rath, has formally confirmed the presence of Irwin's turtle in the Lower Burdekin for the first time since the 1990s.
Dr Villacorta Rath said the current thought was that the species had disappeared from the area.
"Since the Burdekin Falls Dam was built, the ecosystem changed dramatically, and the water now has high levels of turbidity all year round," she said.
"However, we have found trace DNA of this species in many areas downstream from the dam, and this indicates the species is currently there."
The researchers collected water samples from 12 sites in the Lower Burdekin via helicopter.
Using an Environmental DNA method, or eDNA, they found the Irwin's turtle genetic material in multiple samples.
"If we think about these turtles that spend their whole time underwater or a fish, or a frog that also spends time underwater, there is shedding of cells," Dr Villacorta Rath said.
Conservation breakthrough
The eDNA method has been a breakthrough for researchers who have struggled to conduct visual surveys of the turtles.
The Irwin's turtle will rarely surface to breathe.
"They can breathe through their noses like other freshwater turtles, but they [mainly] breathe through their cloacas — their bums," Dr Villacorta Rath said.
Snorkelling surveys are also not possible in the Lower Burdekin due to the presence of crocodiles.
Dr Villacorta Rath said the new data on the Irwin's turtle would inform conservation efforts.
"Environmental DNA is a sensitive tool for the detection of cryptic species such as the Irwin's turtle," she said.
"The species especially not listed under the EPBC Act, Environmental Protection and Biodiversity Conservation Act because there is lack of data.
The Irwin's turtle is commonly found in Broken River and Bowen Creek but has been considered rare in the Burdekin region.
