Release of thousands of Corroboree Frog eggs brings hope

Release of thousands of Corroboree Frog eggs brings hope

Keepers from Taronga Zoo and Zoos Victoria have released over two thousand zoo-bred eggs into the wilds of Kosciuszko National Park to bolster the critically endangered Southern Corroboree Frog population.

The vital eggs, bred at Taronga and Zoos Victoria, were carried high into the mountains and carefully released into disease-free enclosures to give them the strongest chance of survival.

It’s believed less than 50 mature frogs remain in the wild due to a deadly chytrid fungus. The fungus prevents the frogs from maintaining important salt levels, leading to a cardiac arrest.

Through a partnership with the NSW Office of Environment and Heritage, Taronga and Zoos Victoria breed from their insurance population of frogs and release their eggs into natural and artificially created chytrid-free areas to help save the species from extinction.

Taronga curator, Michael McFadden, said: “Only 15 wild males were detected during the January census, mostly at sites where the animals have been reintroduced into the wild.”

“The eggs we released this month will take six months to metamorphose into frogs and then a further four years for them to mature. It’s hoped that these eggs will contribute to giving this species a chance to recover.”

“Frog experts working closely with this species believe that without the breed-for-release program, this species would be extinct within the next two years,” said McFadden.

Southern Corroboree Frogs can be distinguished by bright lines of yellow on their tiny, black bodies. They and other frog species such as the Northern Corroboree Frog and the Yellow-spotted Bell Frog have been brought to the brink of extinction by the fungus.

The joint Taronga and Zoos Victoria breeding program is providing vital insurance for the species’ survival by annually breeding and releasing eggs, tadpoles or mature frogs into the wild. NSW Office of Environment and Heritage coordinates the release of the animals bred by the zoos and then manages the wild populations.

The International Union for the Conservation of Nature (IUCN) has called chytrid the worst infectious disease ever recorded among vertebrates.

“Hope for the species lies in the zoo-based maintenance of the species genetic variation and breed-for-release program. This program has already demonstrated that we can prevent the complete extinction of this remarkable little creature,” said David Hunter, NSW Office of Environment and Heritage threatened species officer.

“The disease is a global problem so thankfully researchers worldwide are working on technologies to potentially abate the impact of this disease, which in the future will give us more options for species recovery and these frogs more hope for survival.”