A Perth nature reserve has become home to the nation's most critically endangered reptiles as 30 young western swamp tortoises are released back into the wild.
Preyed upon by introduced species like foxes, pigs and rats, and suffering from habitat loss and low rainfall, the number of tortoises dwindled to 50 in 1988.
Increasing tortoise numbers is a slow task as they can take eight to 15 years to mature, however a breeding and release program run in partnership with the department of biodiversity, conservation and attractions and Perth Zoo has successfully bred more than 1040 tortoises.
The 30 captive-bred juveniles were released at Moore River Nature Reserve north of Perth, where a population of tortoises was established in 2007.
DBCA's senior research scientist Dr Gerald Kuchling said Tuesday's release was crucial to strengthening wild populations of the tortoises.
"The western swamp tortoise is Australia's rarest and most critically endangered reptile," he said.
"Some of the 146 juveniles previously released there have already reached maturity and started breeding with new hatchlings recorded."
The tortoises are released at around three years as they are "less vulnerable to predators and to drought than hatchlings", Perth Zoo keeper Bradie Durell says.
The program, called Western Shield, is also supported by the University of Western Australia, the Friends of the Western Swamp Tortoise community group and the Ellen Brockman Integrated Catchment Group.
© AAP 2019