Environment

‘They might just disappear’: warning over ‘punk’ turtle’s future

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“Given our study we wouldnt be surprised to find there is a bit of a collapse in the population.”

Ms Connell said turtle researchers respected the “doggedness” of a turtle species which links back to the age of dinosaurs.

“Its such an ancient species that was hanging around when the dinosaurs were here and now potentially under our watch it might just disappear through our failure to act," she said.

Ms Connells CDU Mary River turtle study is the first sample large enough to be used as a baseline survey for the Mary River Turtle.

It is the first rigorous field research on Mary River Turtle since 2001 and 1998.

The Mary River turtle is under threat.

Photo: Zoological Society of London

“The issue is they are much larger and older and the youngest class sizes are all missing compared to a 2001 study,” Ms Connell said.

“Our survey shows this young cohort is really in dire trouble,” she said.

“They made up only about 8 per cent of the turtles we captured in the river,” she said.

The three-year study found:

  • There were about 10,000 Mary River turtles;
  • The turtles, on average, were getting older;
  • Some turtles were now 100 years old;
  • There were very few young turtles;
  • Large numbers of catfish and wild dogs are eating baby turtles; and
  • Mary River turtles are impacted as river levels lower when drinking water supplies are taken for Sunshine Coast and Brisbane.

The critical groundwork and trapping of Queenslands bum-breathing Mary River Turtle was only completed at Easter.

Mary River Turtle being measured by Charles Darwin researchers including Marilyn Connell (left).

Photo: Facebook

Ms Connell says the major problem shown by her three-year survey (2015-17) of 480 turtles is there are very few young Mary River turtles and even fewer living until they can breed.

“We found very few that would be less than 15 to 20 years old; very few,” she said.

Young Mary River Turtles are killed by cars and eaten by dogs, foxes and goannas on the river edge and by booming numbers of fork-tailed catfish and other competing fish species in the Mary River, she said.

Ms Connell, who was awarded Churchill Fellowship for her turtle research, said her team has collated results from 480 turtle trapping nights on the Mary River from 2015 until Easter.

She estimates there are 10,000 Mary River Turtles in the river.

Mary River Turtles are like humans and females become sexually mature and able to breed after they grow to 15 to 20 years of age.

They live until they are 100 years of age.

The endangered, bum-breathing Mary River Turtle was only discovered in 1990 by Sydney researcher John Cann.

It was yesterday identified as the worlds 30th most endangered reptile by the prestigious Zoological Society of London (ZSL's) Evolutionarily Distinct and Globally Endangered (Edge) Reptiles list.

That is based on the fact that the turtle's biological chain travels back 50 million years to find a biologically-close relative.

By contrast, Ms Connell said her team trapped “more than 400” turtles and measured their shells (carapace) to understand the age of the turtles.

The results will be published this year in several scientific journals.

Ms Connell said it was difficult in 2018 to say if the Mary River Turtle population has increased or decreased.

“We dont know that because no-one has ever done a baseline study before,” Ms Connell said.

“Weve done it with standardised procedures so someone in the future can come back and do a comparative study and actually say if the population is increasing or decreasing.

The endangered Mary River Turtle is found only in the Mary River behind the Sunshine Coast.

It is not found in still water and needs water flowing over rocks to generate oxygen on the water surface because “it breathes through its bum,” she said.

“They tend to hang around the ripple zone in rivers, where there is a lot of oxygen,” Ms Connell said.

Then-federal environment minister Peter Garrett rejected the Traveston Crossing Dam in 2009.

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Tony Moore

Tony Moore is a senior reporter at the Brisbane Times

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