Stalking the Mock Turtle
New Scientist vol 171 issue 2307 - 08 September 2001, page 28
In the turtle-meat market of America's South, shady deals put rare species in jeopardy. Biologists Joe Roman and Brian Bowen track down fraud from swamp to table
IT'S 5 am. We pull on muddy jeans, confront a horde of hungry insects, and pour a can of beans for breakfast. Then we paddle up a narrow channel, curtained with Spanish moss and poison ivy, and pull the traps set late the night before. If we're lucky, one of the nets contains a turtle, restless after a night of trying to escape the funnelled hoops. We slog it onto shore, heave it onto portable scales, and then flip it on its back to draw off a few drops of blood from the snakelike tail.
But fieldwork doesn't always resemble mud wrestling, even for wildlife biologists. One evening, our collection site is one of the finest Cajun restaurants in New Orleans, where a jacket and tie are the appropriate attire and the only vegetation is the 300-year-old live oak in the garden. Instead of setting nets for our sample, we make a reservation for two.
After serving the wine, our waiter arrives with a porcelain bowl filled with thick, dark broth. When he turns his back, we scoop a brown cube of meat from the turtle soup au sherry and drop it in a blazer pocket lined with plastic. Our newest genetic sample will join a freezerful of turtle purchased in restaurants, seafood markets, turtle farms, rendering plants, and even on the Internet. Later, back in the lab, we'll analyse its DNA to discover whether the meat came from legally harvested turtles or from endangered species protected by law. Our sampling may also uncover a sleight-of-hand we call the "mock turtle syndrome"--a practice that could alter the conservation prospects of not just turtles but other overexploited species as well.
One of the most prized--and feared--turtles in the channels, streams and oxbow lakes of the South is the enormous alligator snapping turtle. Though they are found in every major river between Florida and Texas, you can live along the Mississippi, the Apalachicola, the Perdido, the Suwannee or the Pearl and never see one. The alligator snapper's furtive habits contribute to its dark esteem, as do its powerful jaws: legend has it that the alligator snapper can amputate a man's hand with one bite. That's a bit of an exaggeration, but not much of one. A few years ago, one of the beasts nabbed the thumb of our colleague Paul Moler, a herpetologist with the Florida Fish and Wildlife Conservation Commission. How did it feel? "Not too bad," he says. "Did you ever get your thumb closed in a car door?" Fortunately for Moler, he was able to poke a screwdriver into the crook of the turtle's jaw and wedge himself free. It was also fortunate that Moler was caught by a 5-kilogram juvenile. Full-grown males can weigh more than 90 kilograms, with a metre-long shell as tough as a beer keg. There aren't many predators that can challenge this monstrous turtle.
Except people. Inside the carapace is a tubful of red meat, making a snapper irresistible to hunters armed with such simple traps as trotlines--lines with multiple hooks--and hoop nets--tunnel-like nets closed at one end. It takes a long time for an alligator snapper to reach the size of a manhole cover, but these river-dwellers may reach enormous ages, perhaps 100 years or more. Such longevity means that alligator snappers, like whales and other late-bloomers, may not be able to withstand intensive harvest. With a few traps, a small boat and knowledge of turtle habits, a trapper can quickly deplete a local population. Al Redmond, who worked the Flint River in Georgia during the 1970s, reported to biologist Peter Pritchard that he could harvest 1000 pounds--450 kilograms--of alligator snappers per day. At that rate, an entire river could be emptied of large turtles in a year.
Many Southern states, faced with decreasing snapper populations, closed down trapping in the 1980s. But Louisiana continues to permit commercial exploitation, and there is anecdotal evidence that alligator snappers are poached in Alabama, Florida and Mississippi for the market in New Orleans. Could we prove it?
One October morning at dawn, we head up the Santa Fe River in northern Florida with Moler. On the banks, sweet gum and saw palmetto trees squeeze their way through the formidable front line of bald cypress. Sliders and cooters--common river turtles--bask on fallen trees, and an alligator slides into the river just below our first trap.
Our first three nets are empty, though something has stolen the fish-gut bait from one. As Moler handles the fourth trap, two alligator snappers lift their ghastly heads to breathe. Crouched in the boat, Moler spots two more turtles below--four alligator snappers have spent one restless night in that trap. The largest of the four weighs in at 45 kilograms, and its shell is more than 40 centimetres long. With a kilo of turtle meat retailing for $20, this haul could have brought us $500 if we were poachers. But all we take are measurements and a few drops of blood.
Our DNA analysis of samples like these, many collected by colleague Steve Santhuff, has revealed that most river systems from Florida to Texas hold genetically unique populations, isolated for tens of thousands of years. That confirms the long-held suspicions of naturalists who knew that alligator snappers--unlike their closest relative, the common snapping turtleÖrarely venture onto land or into salt water. If the turtles are hunted out of a river, they won't be replenished by migrants from other rivers. That river's distinctive genetic diversity, the mainstay of evolution, will disappear forever.
But the same isolation that threatens local populations makes it easier to track poachers. Alligator snappers can be legally harvested only from Louisiana rivers, so only turtles carrying the Mississippi River genotype should be on sale in the markets. It was this observation, plus reports of poaching in other states, that prompted us to extend our genetic studies from the Southern bayous to the restaurants and turtle markets of Louisiana.
In a total of 34 turtle-meat samples, we found just one alligator snapper. That's not necessarily good news--it could mean that the big turtle has been hunted to near extinction. Most of the meat we bought in Louisiana was from common snapping turtle, which has a wide distribution in North America, stretching from Mexico to eastern Canada. A few samples matched the Florida softshell turtle, which is heavily harvested for Asian markets. Our worst fear--that sea turtles were still in the trade after a quarter-century of protection--fortunately turned out to be unfounded. But our most surprising result was that a quarter of the meat sold as turtle wasn't turtle at all.
It's not the first time other meat has been passed off as turtle. Green sea turtle was the height of fashion for diplomatic dinners and society banquets in Victorian England. Not everyone could afford this luxury, though, and mock turtle soup--commonly made of veal--became popular in middle-class restaurants and dinner parties. So popular, in fact, that Lewis Carroll gives the Mock Turtle a cameo appearance in Alice in Wonderland. As depicted by illustrator John Tenniel, it is half floppy-eared calf, half teary-eyed sea turtle.
Here in the New World, we have our own mock turtle--the American alligator. Alligators are once again abundant in the United States and protective measures have been lifted. Their meat, now available from farms and wild hunts, brings a lower price than turtle. As turtles become harder to find, our DNA tests show that some butchers are turning to 'gator meat to fill the demand.
This reptilian fraud made us take a second look at other market studies. Genetic researchers Scott Baker and Steve Palumbi found dolphin meat being sold in Japan as more highly prized whale meat, which retails for up to $500 per kilo. Even stranger, five of their "whale" samples matched horse DNA--not a bad mark-up for meat usually destined for dog food. Rob DeSalle and colleagues at the American Museum of Natural History in New York found Mississippi sturgeon roe in tins labelled as the rarer, and pricier, Beluga caviar. And seal penises, which can fetch up to $600 apiece on the Asian aphrodisiac market, often turn out to be genitalia from domestic cattle and wild dogs. (Bull pizzle has to be carved to pass as a pinniped sex organ.) About 25 to 30 per cent of these luxury items, from turtle meat to seal penises, are falsely labelled. We refer to this substitution of a commoner wildlife species for a scarcer, higher-priced one as the mock turtle syndrome, in honour of Carroll.
At first glance, it seems that this replacement could help ease the pressure on overexploited species, allowing them to recover as other animals are harvested. Not so, insists fisheries biologist Dan Pauly at the University of British Columbia in Vancouver. "The notion of relieving pressure is absurd. It assumes that there is a fixed demand. But there is enormous elasticity in the market. If people have more money, they will buy more," he says. In the end, "there is no market magic" to bail out endangered species.
In fact, the mock turtle syndrome clearly has big disadvantages for conservation. A fishmonger who will sell horsemeat for several hundred dollars a kilo isn't likely to baulk at including an endangered species either. Baker and Palumbi have found five endangered baleen whale species, including the enormous blue whale, in the markets of Japan. In July, 15 sea lions were found dead near a tourist resort in the Galapagos. Their genitalia had been removed, presumably for later sale. And these aren't the only marine species in danger. Pauly has documented a persistent pattern of fishing down the marine food web: after prized top predators are hunted out, fishermen turn to increasingly smaller prey, depleting coastlines of marine life.
If even such high-profile species as marine mammals fall prey to the insatiable hunger of the marketplace, how can we expect inconspicuous turtles to fare any better? Alligator snappers are tough, able to break broomsticks in a single snap of their jaws, but they can't escape a persistent set of traps or series of trotlines. The market is relentless, and the mock turtle syndrome enables vendors to play an endless shell game.
On our last trip to Louisiana, we visited a shop on the outskirts of New Orleans, not far from the Mississippi. A man in a white apron told us it was illegal to sell alligator snapping turtle in the US. The turtles were just too rare. Standing in front of a pen of common snappers, he handed us a kilogram of fresh meat.
It was the only alligator snapping turtle we found.