More than 200 million frogs make it onto menus each year, a new analysis finds. Although the actual number is unknown, statistical projections suggest it could be as high as 1 billion, according to Corey J. A. Bradshaw, a mathematical ecologist at the University of Adelaide, Australia. Indeed, his team found data that in France, the amphibians are even served in school cafeterias.
“I work on plants, mosquitoes, whale sharks, just about everything,” he says, analyzing, among other things, their extinction potential. “Last year, I got together with some herpetologist colleagues and others for a paper on the drivers of amphibian extinctions,” he says. It’s a big issue. “Thirty-two percent of all described amphibians are threatened with extinction in some way,” he notes; “22 percent of the remaining species — we know next to nothing about their numbers.”
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Given, Bradshaw says, that worldwide, amphibians are the taxonomic class possessing the highest number of species threatened with extinction, “These guys are already in a pretty sorry state.”
In its earlier analysis, his team had trouble identifying the number of frogs harvested for human dietary consumption. So, once that paper was published, the scientists started hunting down trade statistics on frogs. “As the magnitude of the harvest started to emerge, it just blew us all away,” Bradshaw says. “We had no idea it was so big.”
In an upcoming issue of Conservation Biology, the researchers will report finding that Indonesia has become the epicenter of frog collection. The data also suggest that because Indonesia supplies major middlemen (and probably middlewomen) in Hong Kong and Singapore, these places serve “almost like a laundering operation. By the time [exported frogs] get through their central markets, no one has any idea where they came from — or what species they are.”
Most frogs are sold as skinned and frozen carcasses. Although many are labeled as to species, studies have shown that these identifications are not trustworthy. Moreover, unless a labeled species were threatened or endangered with extinction, few regulations would apply to its importation by consuming nations — principally western European countries, the United States, China and nearby Asian states.
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Unfortunately, the tally misses frogs that will be eaten domestically. Data today exist only for international trade in species. Those that don’t cross international borders remain off the accounting books. And for Indonesia, Bradshaw says, it appears that domestic consumption may now equal somewhere between twice and seven times the number it exports.
Sure, frogs can be farmed, and are raised successfully some places within the United States. However, the husbandry of these hoppers tends to be fairly “finicky,” Bradshaw notes — and beyond the skill set of low-budget operations in the developing world. So most frogs for export continue to be collected from the wild.
With amphibians in dire straits globally, it would help to know which species are being culled for human consumptions, in what numbers, and where. Toward that end, Bradshaw recommends that conservation organizations set up trained people to identify frogs by species at the collection points — preferably before they’re “anonymized” by skinning and freezing. Batches could be tagged by species to keep their identity intact through importation to distant markets.
Programs might even be set up to certify frogs reared in sustainable farming operations.
Explains Bradshaw: “We can’t possibly evaluate sustainable harvests if we don’t know what species are being taken and in what numbers.”