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Melbourne Zoo

Breeding world-first with Baw Baw Frogs

28 October 2018

In a world-first, Zoos Victoria has successfully bred the critically endangered Baw Baw Frog in captivity, slowing down the species’ path towards extinction.

The momentous achievement is the culmination of more than seven years of tireless and dedicated work by the Zoos Victoria team, in conjunction with Baw Baw Frog Recovery Program partners.

The Baw Baw Frog is the only frog that is endemic to Victoria. However, with a population decline of more than 98% since 1980, and less than 1000 individuals left in the wild, their situation is now considered an emergency.

Climate change and the infectious disease Chytrid Fungus have been the two greatest threats facing the Baw Baw Frog’s survival. The highly contagious Chytrid Fungus has been linked with declines and extinctions of other frogs worldwide, including the critically endangered Southern Corroboree Frog.

Melbourne Zoo Amphibian Specialist Damian Goodall said that, since the alarm was raised, Zoos Victoria has been working closely with survey teams on Mt Baw Baw to collect egg masses to raise in captivity, as well as adults to contribute to breeding.

“We have planned and prepared extensively for this program, including designing and constructing specialised breeding bunkers that mimic the frog’s natural alpine habitat, as well as breeding specialty insects that are conducive to the female reproductive cycle,” Mr Goodall said.

“Our staff have been committed to developing the best husbandry protocols, as well as the targeted collection of female Baw Baw Frogs to help secure the genetics of the wild population.”

He said discovering the egg masses laid by the captive bred frogs had been such an exciting moment and a huge relief knowing that we are on the right path to cracking the code with breeding these elusive amphibians.  

The frogs only occur on a restricted section of the Baw Baw plateau in Victoria in an extremely cold, high-altitude habitat. A cryptic and hard to detect species, the frogs find natural soil cavities underground from which to call and lay their translucent eggs in a foam nest.

Unlike most other frog species, developing Baw Baw Frog tadpoles do not swim or feed. Instead, they are nourished by a large residual yolk, whilst hiding under vegetation until they metamorphose into frogs.

And while this tiny brown frog may not be much to look at, they play a valuable role in ecosystems and help to make Australia distinctive.

“Baw Baw Frogs are endemic to the Mt Baw Baw Plateau, losing these frogs would mean the sound of the males chorus will never be heard again, the soundscape of the Baw Baw Alpine Forest will become even more silent,” said Mr Goodall.  

“The lack of a large amphibian within the ecosystem will affect the food chain for other reptiles and birds that would normally prey on this frog. If there is no food source that attracts other species into the area eventually they will move away and less and less species will coexist.”

The recovery team has spent the past few weeks on the slopes of Mt Baw Baw, identifying areas free of the Chytrid fungus and will not be putting all their eggs in one basket when it comes to releasing back into the wild.

“The team will be releasing the majority of the eggs to Mt Baw Baw, but an insurance population of about 10 per cent will also be kept at Melbourne Zoo,” said Mr Goodall.

“I think we got to them just in the nick of time and we will continue to fight the all-too possible extinction of this species.”

Zoos Victoria would like to thank its Baw Baw Frog Recovery Program partners: Little Brown Things, Baw Baw Frog Recovery Team Baw Baw National Park, Baw Baw Shire Council, Deakin University, Department of Environment, Land, Water and Planning, Mt Baw Baw Apline Resort and the University of Wollongong.