Rescuers hope egg drop will be giant leap for rare frog
A FOAM cooler will be the unlikely vessel carrying the young of one of Australia's most endangered species from Melbourne Zoo to the marshlands of Mount Kosciuszko next week.
Inside the cooler will be five plastic tubs containing 60 black eggs each. Resting on moss like jewels on velvet, the precious eggs belong to the striking black and yellow southern corroboree frog.
With fewer than 100 southern corroboree frogs remaining in the wild, the species' critically endangered status means slumming it in a cooler is unusual. Normally this species enjoys the Rolls-Royce treatment.
These eggs started life at Melbourne Zoo's $75,000 amphibian centre, a purpose-built climate-controlled facility that is playing a key role in the captive breeding program in Victoria and NSW.
And although they will travel to their new alpine address in a cooler, it will be a helicopter that drops them at their remote mountain-top home on Tuesday.
Amphibian keeper Raelene Hobbs said while the zoo had been participating in a national recovery program since the mid-1990s, it was the first time it had released corroboree frog eggs into the wild.
Given the dire results of the most recent ''frog census'' taken during breeding season, it's a tactic researchers are hoping will pay off. Between December and April, researchers recorded just nine males calling in the wild and found just one clutch of eggs.
''It probably means there are barely any females left in the wild,'' Ms Hobbs said.
One of the main threats to the frog's survival in the wild is the water-borne disease chytrid fungus, which attacks the keratin in the animal's skin cells. Because frogs breathe through their skin, infected frogs die from asphyxiation.
After releasing frogs and tadpoles in the past, researchers are hoping a new approach might help pull back the wild population from its precarious position.
''The eggs can't get chytrid fungus because they don't have keratin,'' Ms Hobbs said. ''If we continue to release … then evolution might happen in front of our eyes and hopefully the metamorphs might be able to build up a resistance.''
The 300 eggs produced at Melbourne Zoo during March and April will be released with about 500 from Taronga Zoo and 19 from Healesville Sanctuary.
The eggs will be released at three carefully selected sites into 4 degree water and Ms Hobbs said they would hatch within 24 hours.
However, because the frogs only reach sexual maturity at four or five, the effect of introducing eggs to the wild will take years to measure.
''Really, though, we have to release them now because they are going to be extinct in three or four years if we don't,'' she said.
The frog only occurs in the Snowy Mountains region of Kosciuszko National Park. The small ground-dwelling frogs do not hop, but clamber over their mossy habitat.