Captive-Born Manning River Turtles Thriving in the Wild

First-ever use of VHF telemetry on the species – combined with intensive scientific monitoring including viral samples – provides unique baseline data on turtle adaptability, river ecology & disease mitigation

In a nationally significant conservation milestone, Aussie Ark with project partner Western Sydney University has conducted intensive scientific surveys of captive-born endangered Manning River Turtles released into a wild NSW river to reveal high adaptability and survivorship and record first-ever baseline data on river ecology.

In February this year, Aussie Ark released a total of 35 captive-bred endangered Manning River Turtles into the Barrington River of the Upper Hunter of NSW. This cohort included sub-adult turtles hatched in the 2020 breeding season, and juveniles hatched in 2024 and 2025. It was only the second time in the organisation’s history that a rewilding had been attempted with this freshwater turtle species, and a world-first for fitting a number of these turtles with VHF transmitters to relay critical data including distribution and survivability.

The Manning River Turtle is one of three endangered freshwater species included in Aussie Ark’s nationally recognised breeding and rewilding program. The organisation has celebrated three successful breeding seasons of the species. The turtles were bred through Aussie Ark’s specialist conservation breeding program, where eggs are incubated and hatchlings raised until they could be released back into the safety of the river and therefore avoiding predators such as foxes. Prior to release, the turtles were health checked weekly and then conditioned for the wild, with reduced human contact and increased motivation to forage on their own.

Until now, post release adaptability was unknown. But the VHF transmitters changed all that! Since release, Western Sydney University PhD student Pham Thong - mentored by ‘turtle guru’ Professor Ricky Spencer - has returned to the site week after week, locating and mapping the turtles thanks to the VHF transmitters on their shells.

This revealed that the turtles adapted quickly to the river environment, and mapped dispersal which depended on age and size. For example, older turtles moved much further afield that the youngsters with some individuals dispersing over two kilometres from the release site! The data also showed that older turtles explored more deeply, and that all turtles spent most of their time in the slow-moving sections of the river.

Over winter, Mr Thong recorded the turtles' reducing activity, which is consistent with all reptiles due to their cold blood. Mr Thong also compared body mass before and after release and found most turtles had gained weight, which indicates effective food foraging. Another important job was collecting non-invasive swab samples to better understand which viruses are naturally present in healthy Manning River Turtles.

“This will give us an important baseline for monitoring their health and help scientists investigate potential disease outbreaks in the future,” Mr Thong said.

“It’s groundbreaking work, which offers a scientific template for future wild releases Australia-wide and world-wide. It has been a privilege to be part of this program, deploying cutting-edge technology, and witnessing firsthand how well our captive-born turtles are doing back in the rivers where they belong.”

Aussie Ark Co-CEO Hayley Shute said the post-release scientific survey is “so inspiring”.

“It proves that endangered species can be captive-born and raised and adapt well to the wild,” Ms Shute said. “And it also proves that we’re doing everything right in our breeding program at Conservation Ark…from rescuing a species through to offering it a whole new future.”

Aussie Ark will continue monitoring its wild-release cohort for many months to come, including updates on breeding and nesting success.

Please support Aussie Ark’s vital work to save the Manning River Turtle from extinction by making a donation today at aussieark.org.au.