The great French bullfrog hunt

6th September 2005, Comments 0 comments

Ecologists are out to protect French native amphibian species from a voracious American breed threatening the local ecosystem.

They're huge, they're hungry, they're Rana Catesbeiana

Picture this: French hunters stealing out at night in pairs, one with a torch to light up the eyes of their prey, the other armed with a .22 calibre rifle equipped with a telescopic sight and a silencer.

Their quarry? Invaders from the United States -- bullfrogs, to be precise, that bellow like cows and typically weigh in at a hefty 600 grams (1.3 pounds).

This is France, to be sure, but the end game of this hunt is not sautéed frog legs.

 These marksmen are ecologists, out to exterminate the bullfrogs -- a.k.a. Rana Catesbeiana or, in French, les grenouilles taureaux -- that are threatening the local ecosystem.

"A man living in Vayres (30km east of Bordeaux) stocked his pond with them in 1968 as a joke, and a few years later every stretch of water in the region was full of them," said Luc Gueugneau, who works in the government agency overseeing wild animals and hunting.

The bullfrogs live for as long as nine years, hibernating from October to March, but the rest of the time gorging on local frogs, shellfish, insects, and even fledgling birds, said ecologist Mathieu Detaint.

Even their tadpoles have the edge against local frogs. The adults have virtually no predators, and each lay up to 25,000 eggs a year, this compared to 10,000 laid by the local frogs.

Chassez la grenouille

We tried draining the ponds, but it costs a lot and is not efficient enough because there are always some bullfrogs that remain," Detaint said.

One thing that did work, though, he said, was trapping the tadpoles and very young frogs in nets.

 Said Gueugneau: "For the moment, hunting the adults with rifles has proved to be the most efficient way of attacking them, because it gets rid of those able to reproduce."

The hunting is done at night, as that is when the frogs are most active and easiest to spot.

"We carried out five hunts between September last year and this July, killing about 120 of them," Detaint said.

"At the start, the idea seemed ludicrous, but we became convinced little by little because they allowed us to eradicate all the adults at two sites where the system was tested."

The ecologists say they a full-scale eradication programme should be in place by 2007, and hope to fully eliminate the bullfrogs in five or 10 years.

The hunter or the hunted?

France is not the only region to complain of bullfrog infestation.

The bullfrog is the largest frog in California, for example, where as in France it preys on other species and has been held responsible for the complete disappearance of the red-legged frog from the floor of the Central Valley and adjacent Sierra foothills, according to the USDA Forest Service.

Ecologists in British Columbia, Canada have also made appeals to the public to both report sightings of the species and to not release any amphibians bought in pet stores into the wild. And, they add, if you see children catching frogs or tadpoles, stop them; it seems an innocent childhood pastime, said the biologists, but can contribute directly to the artificial redistribution of species like the bullfrog.

The irony, of course, is that these ecologists must battle this one species at a time when frog populations are on a steep, some say catastrophic, decline everywhere in the world. 

The 2004 Global Amphibian Assessment found that one-third of the world's amphibian species -- including frogs, toads, newts and salamanders -- are threatened with extinction almost entirely due to ecological damage.

The frog has been a part of the European diet since the 16th century; now, eight to 10 tons of frog legs are consumed every year, according to French research institute INRA.

Most of the harvest comes from natural reserves, but declining populations mean that restaurants have been increasingly turning to frog farms, farms that sometimes inadvertently cause frog populations to move habitats, as happened with the bullfrog with near disastrous consequences.

August 2005

Copyright AFP and Expatica

Subject: Life in France

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