28 Aug 2013

A golden mantella frog at Chester Zoo is implanted with a fluorescent silicone gel on its leg, which allows keepers to easily identify individuals in their group of 80 frogs. Amphibian experts will monitor the effectiveness of the tags and, if deemed a success, the method will be used to track the progress of the critically endangered species in the wild in their native Madagascar. It’s the first time the technique has ever been attempted on the tiny Madagascan frog, which weighs less than 1 gramme.

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Amphibian experts here at the zoo say that silicone implants could play a part in saving one of the smallest and most spectacular frogs in the world.

Our conservationists are trialing a technique to tag a population of 80 of the zoo’s golden mantella frogs with a tiny amount of fluorescent silicone gel under the skin on their legs.

They hope the implants will ultimately enable them to identify and track the progress of wild populations in their native Madagascar – a move which could help to protect the species.

Dr Gerardo Garcia, Chester Zoo’s curator of lower vertebrates and invertebrates said:

“The technique of injecting a small coloured implant under the skin has never been attempted on these tiny golden mantella frogs before. However, if it works successfully here, then we’ll be replicating this in the wild in Madagascar.

“In the short-term we hope these tags will be allow us identify each of the groups of frogs we have at the zoo – something that’s currently very, very difficult given that they are all about the size of a thumbnail and all look the same. We need to be able to do so we can easily tell who’s who for our own conservation-breeding purposes.

“Then, once we’ve assessed how effective the tagging method is on the zoo’s ambassador group and if it proves to be the success that we think that it will be, we’ll deploy this method in Madagascar with wild populations.

“We have already collaborated with organisations in Madagascar to help to set-up captive-breeding centres in Madagascar which are now successfully breeding the species. If we can tag groups of frogs in this way before we release them, then we’ll be able to track where they go, how long they live and what their survival rate is.

“These frogs are highly threatened in their homeland and this process could play a very important part in their long-term survival.”

The 20mm-long frogs are classed as critically endangered by the International Union for the Conservation of Nature (IUCN), meaning they face an extremely high risk of extinction in the wild.

A programme devised to protect golden mantellas and all other amphibians in Madagascar was set up in 2006. The strategy aims to equip local conservationists with the skills needed to establish safety-net populations of amphibians in captivity, out of the reach of a killer fungus that has devastated amphibian populations worldwide.

Madagascar is one of the only places in the world where the deadly chytrid fungus – a disease which thickens the frogs’ skin and prevents the movement of fluids, causing a chance of heart failure – does not currently exist.

However experts believe it is only a matter of time before the fungus arrives there.

Dr Garcia added:

“Amphibians already face lots of threats, most notably from the destruction of their habitat, however the chytrid fungus could be the last nail in the coffin. It threatens most of the wild amphibian species around the globe with extinction and it’s probably the first time ever that a disease has threatened to wipe out an entire class of animals.

“There’s a very real chance of a new epidemic here and that’s why it’s vitally important that careful, professional ex-situ [captive] programmes are in place to buy us more time and give the species a lifeline until the threat of chytrid can be resolved.”

If the tags are a success then Dr Garcia will travel to Madagascar in late January to meet up with Madagascar Voakaji – a local NGO – to train local conservationists on how to inject them.

Before receiving their fluorescent implant, the golden mantella frogs from Madagascar are weighed and show to be less than 1g. The frogs are critically endangered in the wild with their main threats being trade, environmental pollution and the alteration and destruction of their habitat.

Chester Zoo’s curator of lower vertebrates and invertebrates, Dr Gerardo Garcia, prepares to inject a frog with a thin strip of silicone gel. The implants will enable keepers to easily identify individuals in their group of 80 frogs.

Dr Garcia shows a steady hand to carefully inject the gel under skin on the tiny frog’s thigh. It’s the first time the technique has ever been attempted on the tiny, 20mm-long amphibians.

Keepers ensure the gel, which is mixed with a hardening agent so that it quickly sets, has been correctly implanted by checking it glows ultra violet using a special torch.

The frog is placed on a glass screen and the implant viewed from underneath. Amphibian experts at the zoo will monitor the effectiveness of the tags and, if deemed a success, the method will be used to track the progress of the critically endangered species in the wild in their native Madagascar.

Each of the 80 frogs are returned to their exhibit where they will be carefully monitored by keepers and research staff. Once satisfied that the implants work, Dr Garcia will then travel to Madagascar in late January to work with Madagascar Voakaji – a local NGO – to train local conservationists on how to inject them.

The implants should allow amphibian experts to track where the frogs go, how long they live and what their survival rate is – vital information in the bid to protect the highly-threatened species.