Yellow-spotted bell frog back from the brink

By AG Staff 23 March 2018
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Keepers from Taronga Zoo have released 200 juvenile yellow-spotted bell frogs into the wild.

THE CRITICALLY endangered yellow-spotted bell frog (Litoria castanea) has narrowly escaped extinction thanks to a successful breeding program at Taronga Zoo.

Thought to be extinct from the wild for 30 years, a small population of the frog was later discovered near the town of Yass in NSW back in 2009, from which an insurance population was collected by the zoo.

Since then, the small population of frogs has bred tadpoles that have metamorphosed into 250 healthy juvenile frogs.

Yesterday, with the assistance of the NSW Office of Environment and Heritage, Taronga released 200 of these juveniles back into the area they were found, in a bid to re-establish wild populations.

“With so few animals to work with, breeding has proved difficult and several different strategies have been implemented in the attempt to get the last of the species to reproduce,” said Michael McFadden, Supervisor of Taronga’s Herpetofauna Department. 

yellow spotted bell frog

(Image Credit: Taronga Zoo)

Michael credits the success of the breeding program to his team’s ability to replicate the frog’s natural habitat at the zoo.

“November is the peak of their breeding season and several of the males began calling, which is the strongest indication we have ever had that they might breed,” Michael said.

“We were thrilled when we noticed that a couple of females had laid eggs in the pond underneath some vegetation in two distinct egg masses.

“We are very pleased to report that a significant proportion of the eggs have developed into juvenile frogs.”

Like many of Australia’s native frogs, the yellow-spotted bell frog populations crashed following the arrival of chytrid fungus, which transmits disease by releasing zoospores that attack the keratin in frog skin and halts the flow of electrolytes.