Captive-raised tadpoles

Frogs traditionally have a high mortality rate of eggs. That is, a lot of eggs may be fertilised but only a small percentage might reach adulthood. One method of increasing a population's size is to increase the percentage of eggs that reach the tadpole stage (and therefore increase the number that become adult frogs.

Over a 5-year period, the recovery team removed some egg masses from the wild and raised them to tadpole stage at the Amphibian Research Centre in Melbourne. The tadpoles were returned to the identical places on the mountain and released.

Take a photographic journey with us as we look at the process.

The Snowy Mountains

The corroboree frog is found only in the Snowy Mountains in New South Wales. Many of the sites are very remote.

Frost hollows

The boggy treeless areas on the high-plains are the habitat of the frog. These are the places where the recovery team may find frogs calling and potentially breeding.

Egg deposition sites

When the team have identified a breeding site, they listen carefully and mark the exact spot where the male frog is calling from. This is the place where they will later find an egg mass. These sites are marked and protected by small enclosures.

The frogs deposit eggs in mossy "nests" and the male frog will usually stay by the eggs as they develop. The recovery team remove some of the egg masses from the nests and they are transported to Melbourne so they can be expertly cared for in favourable conditions.

Increasing survival

Some egg masses that are left on the mountain may be in danger of drying out - which means no tadpoles would survive. The solar-powered pump and water tank shown below ensure that some sites are protected from drought or prolonged dry spells.

The Amphibian Research Centre

The corroboree frog eggs are held in quarantine at the Amphibian Research Centre. The eggs have a much higher survival rate here and a very large percent of them will reach the tadpole stage.

Back to the wild

Eventually the frogs are returned to the mountain and are released as close as possible to the site that they were collected from. Monitoring will tell us whether or not increased survival to tadpole stage means that more frogs will survive as adults.