Researchers from Charles Darwin University (CDU) are trying to find a solution to help recover the Mary River turtle population by tracking their movements with an acoustic device.
Dr Mariana Campbell from CDU's Research Institute for the Environment and Livelihoods have undertaken a field exercise in Queensland, where they installed small acoustic devices on turtles released into the water.
Each device contains a unique code that changes once activated by the enzyme in the predator's stomach if the turtle gets eaten.
She suspects that most of the turtles are predated by oversized catfish native to the Mary River, and the population of freshwater turtles are almost depleted.
"Through our research, we hope to find out the culprit for this population decline and a solution to preserve the population," Dr Mariana Campbell said.
"Freshwater turtles don't get as much attention as sea turtles, maybe because they are not as charismatic and are not well studied," she said.
"We hope to develop a solution to help recover the freshwater turtle population, which can be applied to other species in Australia and around the world."
The research is a collaboration between CDU, SunWater water authority and the local community group Tiaro & District Landcare Group, and is a long-term collaboration with local conservation groups and the community.
In the 1960s and 70s, there was extensive egg collection of the Mary River turtles for the pet trade, causing the population to decline rapidly.
There is a local nest protection program that aims to preserve the number of turtles, but Dr Campbell's research suggests the hatchlings have low survival rates once in the water.
"We are trying to figure out what is happening to the turtles once they are in the water, also which head-starting program is more viable," Dr Mariana Campbell said.
In a recent field trip, Dr Campbell released a batch of 15-month-old turtles to Mary River and continued monitoring their movements through the tag.
An array of listening devices has been installed underwater to actively track the turtles' locations. If a turtle gets eaten by a catfish, the catfish can be tracked down and caught if needed.
Dr Campbell plans to release another batch that tests the viability of the head-starting program, which involves keeping the turtle hatchlings in captivity until they reach a certain age.
The research will help us understand the diminishing Mary River turtle population and find ways to revive the species.
