Investigating Frog Deaths
In late July scientists became aware of reports of dying frogs, many of them green tree frogs. An interview on ABC radio which was followed by an article in ‘The Conversation’ attracted responses from community members across the country about dead and dying frogs in their localities.
Scientists at the Australian Museum, the Australian Registry of Wildlife Health at Taronga Zoo and a forensic unit in the Department of Planning, Industry and Environment are trying to solve the mystery of what is killing these Australian frogs.
Since late July scientists have collected reports of 31 different species affected in almost every state and territory. Among the 30 native species are endangered frogs such as the green and golden bell frogs, southern bell frogs and the giant barred frog. The one invasive species is the cane toad.
While 60% of the frogs found to have been affected are green tree frogs, this large percentage may be explained by the fact that they are a common species found in and around people’s homes.
Three different investigations are under way. At the Australian Registry of Wildlife scientists are dissecting the dead frogs, looking for indicators of disease and taking samples from their livers, kidneys, blood and stomach where possible. The Australian Museum scientists are studying the animals at a molecular level, swabbing the dead frogs and taking a skin sample before running DNA tests to check for pathogens that might indicate a virus or fungus. The forensic unit is running toxicology tests for pesticides, heavy metals or other environmental toxins.
While the number one candidate for the deaths at the present is chytrid fungus, the researchers believe it’s too early to determine if chytrid is responsible. Chytrid is a fungus responsible for the decline of more than 500 amphibian species globally.
As frogs absorb the environment through their skin, they are an important indicator of environmental health. Furthermore, they occupy an important place in natural ecosytems. So, finding the cause of this mortality and hopefully combating that cause or causes is important.