Catherine Brahic, New Scientist 19 Jan 09;
Are frogs being eaten to extinction? We're used to hearing about how disease, climate change, and habitat degradation are endangering amphibians, but conservationists are warning that frogs could be going the same way as the cod. Gastronomic demand, they report, is depleting regional populations to the point of no return.
David Bickford of the National University of Singapore and colleagues have called for more regulation and monitoring in the global frog meat market in order to avoid species being "eaten to extinction".
Statistics on imports and exports of frog legs are sparse as few countries keep track of the amount of meat harvested and consumed domestically.
According to UN figures, global trade has increased in the past 20 years. France - not surprisingly - and the US are the two largest importers; with France importing between 2500 and 4000 tonnes of frog meat each year since 1995.
But although frog legs are often thought of in the West as a quintessentially French dish, they are also very popular in Asia.
Bickford estimates that between 180 million to over a billion frogs are harvested each year. "That is based on both sound data and an estimate of local consumption for just Indonesia and China," he says. "The actual number I suspect is quite a bit larger and my 180 million bare minimum is almost laughably conservative."
Local depletion
Even top French chefs may be unaware of where their frogs are coming from. Bruno Stril, teaching chef at the Cordon Bleu school in Paris, France, is unsure where his suppliers source their frog legs. "I would like for them to come from France," he says. But he expects that most of the meat comes from other countries.
Stril is on the right track. Indonesia is the world's largest exporter of frog meat, exporting more than 5000 tonnes of frog meat each year, mostly to France, Belgium and Luxemburg.
Bickford and colleagues say European kitchens initially found their own supplies in the surrounding countryside, but the fact that they are now importing from Asia suggests local populations were over-harvested. This, they say, could be a sign that frog populations, like many fish populations, will be harvested to near extinction.
"Overexploitation in the seas has caused a chain reaction of fisheries collapses around the world," the researchers write. "This experience should motivate better management of other exploited wild populations."
Anonymous legs
James Collins, of the World Conservation Union, says the Californian red-legged frog offers some evidence for the theory. This species was first harvested for food in the 19th-century California gold rush and eventually the population began to crash.
However, Collins cautions that "at the moment we have no data indicating that commercial exploitation has led to the extinction of any amphibian species." He says the Bickford team's evidence is worrisome, but inconclusive.
Most harvested frogs are skinned, butchered and frozen before being shipped overseas. This makes it difficult to know exactly what species are being killed. Indonesia is thought to mostly export crab-eating frogs, giant Jana frogs, and American bullfrogs. How much meat is consumed within Indonesia's borders is also something of a mystery. Some studies suggest it could be between two and seven times what is exported.
"There are a heck of a lot of frogs being eaten," says Bickford. "Much more than most people have a clue about."
Journal reference: Conservation Biology (DOI: 10.1111/j.1523-1739.2008.01165.x)
Frogs 'being eaten into extinction'
It may not be everyone's favourite food, but the humble frog is in danger of being eaten into extinction, a group of scientists have warned.
Bonnie Malkin, The Telegraph 21 Jan 09;
A growing appetite for frogs legs at dinner tables in Europe and Asia has sharply increased the consumption of the French delicacy in the past 20 years.
Scientists from the University of Adelaide, working with colleagues in Singapore, Canada and the US, now believe the global trade in amphibians is between 200 million to one billion per year.
"Frogs are already in a bad way throughout most parts of the world," said ecologist Professor Corey Bradshaw, from the university's school of earth and environmental sciences.
"The common perception is that a few specialty restaurants in France may serve frog legs to a select clientele, but you know the USA is probably the next biggest importer and they're not really known for their appreciation of frog meat," he said.
Prof Bradshaw said frogs were eaten everywhere from school cafeterias to exclusive restaurants.
He said frog numbers were suffering because there was now year-round demand for sauteed frogs legs, previously a seasonal dish, in restaurants across the world.
Large numbers of wild frogs were harvested for the restaurant trade because the possibility of being poisoned by a frog was relatively low.
With more than 100 classes of amphibians already becoming extinct during the past few years, experts predict that up to 3,000 species are in danger of disappearing from the planet.
Prof Bradshaw said frogs played a vital role in almost all eco-systems and that something needed to be done by humans now to prevent a devastating "chain reaction".
"Wild populations have depleted and countries have become concerned only now due to not having insect control for agricultural production."
The researchers have called for mandatory certification of frog harvests to improve monitoring and help the development of sustainable harvest strategies.
A billion frogs on world's plates
BBC News 22 Jan 09;
Up to one billion frogs are taken from the wild for human consumption each year, according to a new study.
Researchers arrived at this conclusion by analysing UN trade data, although they acknowledge there is a lot of uncertainty in the figure.
France and the US are the two biggest importers, with significant consumption in several East Asian nations.
About one-third of all amphibians are listed as threatened species, with habitat loss the biggest factor.
But hunting is acknowledged as another important driver for some species, along with climate change, pollution and disease - notably the fungal condition chytridiomycosis which has brought rapid extinctions to some amphibians.
The new research, to be published in a forthcoming edition of the journal Conservation Biology, suggests that the global trade in wild frogs has been underestimated in the past.
"Frogs legs are on the menu at school cafeterias in Europe, market stalls and dinner tables across Asia to high end restaurants throughout the world," said Corey Bradshaw from Adelaide University in Australia.
"Amphibians are already the most threatened animal group yet assessed because of disease, habitat loss and climate change - man's massive appetite for their legs is not helping."
Amphibians are farmed for food in some countries but these animals are not included in the new analysis.
Exporting extinction
Indonesia emerged from Professor Bradshaw's analysis as both the largest exporter of frogs - 5,000 tonnes per year - and a major consumer.
This has raised concerns that it may soon experience the declines induced by hunting that have been seen elsewhere in the world, notably in France and the US, where species such as the Californian red-legged frog have crashed.
The researchers suggest that the amphibian trade may mimic the situation with global fisheries.
"Harvesting seems to be following the same pattern for frogs as with marine fisheries - initial local collapses in Europe and North America, followed by population declines in India and Bangladesh and now potentially in Indonesia," said Professor Bradshaw.
"Absence of essential data to monitor and manage the wild harvest is a large concern."
The researchers suggest establishing a certification scheme so exporters would have to prove that their animals had been hunted sustainably.
However, a large portion of the trade in amphibians for the pet trade is conducted illegally, and experts say customs officials in many countries are ill-equipped to spot and deal with illegal consignments.
