Captive Growing Tadpoles Give Giant Victoria Burrow Frog Hope | Victoria
Fifteen tadpoles belonging to rare species of Victorian frogs grew legs in a milestone in a critical conservation program days after being officially declared a separate subspecies.
The “mysterious” giant burrowing frog is an endangered species found in New South Wales and remote areas of central and eastern Gippsland.
Little is known about the “rare and cryptic” species and so far they have never been kept or bred in captivity.
This means that amphibian specialist Adam Lee, who oversees the Zoos Victoria conservation program, does not have a clear guide for the species.
“I was definitely a helicopter dad for a while at the start,” Lee said. “By checking them daily. Making sure the water conditions were good, making sure we didn’t have any water quality issues and making sure they were feeding well and there were no signs disease.
“We had over 100 tadpoles in the initial collection. In the wild there is a certain level of mortality, but so far we are doing very well and we have done them all. Having zero mortality so far is a good thing, and you’d expect him to go through the various stages of development. “
Lee said about 15 tadpoles have “metamorphosed” so far – the process by which tadpoles have legs and grow into adult frogs – and he hopes more will follow soon.
“Their tadpole stage can last anywhere from three to 11 months and over the next three to four months we expect them to undergo a metamorphosis,” Lee said.
“The main focus at the moment is to establish captive breeding and ensure that we can breed them throughout the life cycle. Metamorphoses into frogs, then breeds frogs to lay eggs.
The species grows to the size of a cricket ball and the young frogs are already larger than other comparable species that have been involved in similar conservation programs, such as the critically endangered southern corroboree frog.
Dr Jodi Rowley, a frog biologist at the Australian Museum, said every success of the program should be commended, especially as the southern population of the giant burrowing frog has been recognized as a genetically distinct subspecies.
“We thought they were a bit distinctive before, but now it’s official,” Rowley said. “The giant burrowing frog has been officially divided into two subspecies. This means that the southern populations of the species, which I believe are involved in the program, are now even larger. “
The distinction was confirmed in an article published Monday in the journal Zootaxia which found that the southern and northern populations were genetically distinct.
The Victoria Zoo program began in March when field researchers found the tadpoles in a remote area of Gippsland following above-average rainfall.
The number of frogs has been affected by logging, land clearing, predation by feral cats and dogs, and diseases such as the chytrid fungus which attacks their skin.
The species was further threatened during the black summer 2019-2020 bushfires, making individuals held at the Melbourne Zoo a critical insurance population for the species.
Dr Scott Clulow, Honorary Associate Lecturer in Newcastle University’s Amphibian Research Group, said the news was “fantastic”, but the next step in the process – rearing the frogs – could turn out to be “hard”.
“It’s a process of experimentation,” Clulow said. “We can do things to help them like we can do with mammals and even humans. But there are a lot of subtle environmental cues that are often involved in the reproduction of frogs and they differ a lot from species to species, so it takes a lot of work to determine the required conditions.