Endangered Kroombit tinker frog bred in captivity after years of trying

After two decades of trial and error, a team of scientists has finally bred the Kroombit tinker frog in captivity in the hopes of preventing its extinction.

The frog is thought to number 200 at best and is found only in small patches of rainforest at Kroombit Tops National Park, a plateau about 70 kilometres south-west of Gladstone in central Queensland.

Ed Meyer, from the Queensland Frog Society, says the breeding plan was first hatched in the early 2000s when he and others became aware of the frog's decline.

There was little the team could do until they had the support of a zoo, and in 2008 the Currumbin Wildlife Sanctuary on the Gold Coast came on board with a dedicated frog-breeding facility.

It was then another 12 years of trial and error before this hatchling.

"We've had our first tiny metamorph – a recently transformed tadpole – emerge from the tank," Dr Meyer said.

"We've been looking for spawn and tadpoles since the mid-1990s, and despite intensive searches through the 2000s, we failed to find any," Dr Meyer said.


The team finally had a successful spawning with the small number of frogs they had in captivity, which allowed them to observe the eggs and tadpoles of this species for the first time.

"This was a real thrill," Dr Meyer said.

"We've got a fresh clutch that was laid a few days ago, so hopefully we'll have a few more tadpoles and metamorphs that come through in the next few months."

Leading up to this moment, the team had been developing breeding techniques using less-threatened species, including the Eungella tinker frog.

"We're planning on raising our metamorph Kroombit tinker frogs through to adulthood and eventually release the captive-bred adults into the wild," Dr Meyer said.

It could take up to two years before the recently emerged froglet is ready to breed, and the team will hang on to a small number.

"Female tinker frogs are very difficult to locate in the wild because they don't call loudly, so we're likely to hang on to captive-reared female frogs especially," Dr Meyer said.

"It would be great to get numbers up into the hundreds, high hundreds and, at some point into the thousands, but whether that's achievable, we just don't know."

Jodi Rowley, the curator of Amphibian and Reptile Conservation Biology at the Australian Museum, says this breeding breakthrough is exciting.

Many species of frogs were very difficult to breed in captivity because they needed specific environmental conditions, which were unknown, and it was a matter of trial and error, she said.

"So it is amazing news that these tricky little frogs that breed in clear, rainforest streams that are very hard to replicate in captivity have been bred in captivity," Dr Rowley said.

She said she hoped the frogs would be able to persist and recover themselves, but in several instances in Australia, it was due to captive breeding and release that some breeds are still in the wild.

Global demise

Frogs have not done well globally, and in Australia four known species are now extinct with another three dozen under threat.

However, the exact number is unknown because the amphibian is difficult to research.

While shrinking environment and pests are some of the reasons behind the decline in frog populations, the primary threat has been the amphibian chytrid fungus.

"We think this was introduced from overseas, possibly Asia, a long time ago and our frogs weren't used to it, so they declined pretty rapidly," Dr Rowley said.

"At the time, no one really knew what was going on as all of a sudden, frogs, particularly those on the east coast were just disappearing."

The fungus affects the frog's skin, which is important to them for breathing and drinking, and it wiped a few species out.

"It's still impacting our frogs today," Dr Rowley said.

There is some good news, as some frog populations that had disappeared are now re-appearing, such as the southern barred frog in northern NSW.

"It appears that frogs can bounce back if they're given the opportunity, but unfortunately it's likely too late for many species."

Dr Rowley said the disappearance of frogs was not only a loss of natural history, but they also played an important part in ecosystems.

Frogs ate many invertebrates, including pest species, tadpoles ate algae and helped keep waterways clear, and frogs were in turn eaten to support other animals in the ecosystem.

"Unfortunately in places where frogs have disappeared, we have noticed the consequences and nothing kind of steps up and fills the role of frogs, so it is really important that we keep them as part of our ecosystem."