Is Your Dinner Endangered? DNA Detectives Investigate

Scientists deploy genetic forensics to protect overhunted animals

What Species Are You Eating?

John B. Carnett

In the ongoing campaign to protect endangered animals, forensic investigators can already identify the food on your plate. Now they are working on advanced methods of intercepting even the most carefully disguised contraband - be it tuna, caviar or bushmeat. Their ultimate goal: pinpoint where the goods came from, and stop the hunting of endangered species at the source.

1. Identification

Last May, I visited a sushi restaurant in Manhattan with Sergios-Orestis Kolokotronis, a biologist at the American Museum of Natural History, to learn what scientists can do to protect endangered animals—in this case, bluefin tuna. Some species of bluefin have been fished to near extinction, and many sushi restaurants still serve those species, but on the day of our visit the menu identified the neat rectangles on our plate—trimmed of eyes, skin and other identifying features—simply as "tuna," "fatty tuna" or "medium fatty tuna." They could have been just about anything. The logical first step to protecting tuna, it seems, is to identify it, and to that end Kolokotronis and his colleagues have developed a lab test that would, within a few days, reveal our meal's true identity. "You need just this little bit here," he said, prodding the ruby-colored muscle with his chopsticks. "This contains a lot of DNA. But we'll take more, just in case."

As I ate, Kolokotronis laid out the larger scheme. His hope was that someday the museum's genetic techniques could be simplified to the point that concerned consumers would be able to use an inexpensive handheld device to identify any number of the hundreds of rare animals that might wind up on their table or in their shopping bag. His mentor, George Amato, who directs the museum's Sackler Institute of Comparative Genomics, has also led the development of similar means to identify lion, monkey and whale meat, not to mention pills made from seal bones and even crocodile-skin boots. That knowledge could be transformative. "Sushi is one of my favorite things to eat, but the tuna project has totally changed my perception," Kolokotronis said. "I started asking, 'What am I eating?' And then I refrained from eating bluefin, period."

Mystery Meat

Unidentified chunks of frozen meat await DNA testing.John B. Carnett

Such methods have already proven useful. Even skilled taxonomists and caviar dealers, for instance, were unable to identify the real contents of unlabeled tins of caviar until the mid-1990s, when scientists at the museum developed an early genetic forensic tool that could identify different types of sturgeon from DNA markers in their eggs. When they used the new test to survey gourmet shops in New York City, they discovered that a quarter of all caviar was mislabeled. The result was an enlightening consumer story, and it laid the groundwork for researchers at the U.S. Fish and Wildlife Service's forensic laboratory in Ashland, Oregon, to develop their own DNA identification tests, which in turn made possible a far more important outcome. In 1997, drawing on this newly available means of enforcing trade restrictions, the parties to the United Nations Convention on the International Trade in Endangered Species, or CITES, voted to regulate the trade of all endangered sturgeon.

Inspection Room At A U.S. Fish And Wildlife Services Facility

Laura Allen

As I finished my own possibly endangered meal, Kolokotronis explained that he hoped the fight to protect bluefin might undergo a similar process: More and better data about what people are eating might raise public awareness and help governments take concrete steps to regulate trade. Certainly I came to regret my own meal, delicious though it was, when Kolokotronis e-mailed a few days later with the test results. The three samples of generic tuna that I had ordered were all Thunnus thynnus, better known as Atlantic bluefin, the population of which may have declined by 80 percent since 1950.

Caviar

The majority of the world's caviar comes from the Caspian Sea, where sturgeon are critically overfished.John B. Carnett

But identifying what is on the plate will not in itself protect endangered animals. After all, many people will want to authenticate bluefin, or monkey meat, or whale, or something else precisely so they can eat it. When representatives gathered in Doha, Qatar, this March for the latest CITES conference, they voted on, among other things, whether to ban the trade of Atlantic bluefin. "The CITES proposal for bluefin named the new genetic methods as essential for enforcement," Amato says. Identification was helping. But Japan, which consumes 80 percent of the world's bluefin catch, successfully lobbied against the ban with what apparently amounted to an even stronger argument—a ban would damage exporters' economies.

Most conservationists expect that the Atlantic bluefin trade will eventually face stricter regulation, but trade in the fish will probably continue, especially as prices for the newly forbidden items spike. Then the question will be how to keep endangered species from reaching consumers in the first place. For that, scientists are developing even more advanced methods that will identify not just what kind of animal is at hand, but where the animal was captured. In the future, even the smallest, most processed animal fragment—a snippet of tanned leather, say, or a speck of bone—could lead authorities back to its source. This ability to draw so much data from such ambiguous material, scientists say, is critical to enforcing existing laws, enacting new ones and, ultimately, to keeping imperiled species from extinction.

Capturing a Dwarf Crocodile

A hunter in a wetland reserve in the Republic of Congo captures a rare dwarf crocodile. Poachers prize the animal for its meat, not its hide, which is hard like armor.Courtesy of Mitch Eaton

2. Interception

A significant portion of the wildlife contraband that is captured in the U.S. is captured at John F. Kennedy International Airport in New York City. Every day, about 80 Customs and Border Protection staffers stationed at the airport's cavernous International Mail Facility examine some 650,000 parcels and decide, based on factors ranging from country of origin to package shape, whether any of them are likely to contain drugs, weapons or forbidden animal products. If the answer is yes, they send the packages to an "enforcement cage," where customs officers scan the parcels with x-ray imagers or simply open them up and take a look. On an average day, the answer is "yes" nearly 20,000 times—20,000 packages and 20,000 inspections. "It's an arduous task," said the mail facility's chief, Bill Rivera, when I visited there in June. "Huge."

In cases where suspicious animal products require more scrutiny, an officer calls in wildlife inspectors from a U.S. Fish and Wildlife Service satellite facility just a few miles down the road. I met one of the inspectors, Ryan Bessey, inside the enforcement cage as he examined a carved, cream-colored smoking pipe. "A customs officer believed it to be ivory," he explained. Bessey pointed out that the pipe lacked ivory's dentine lines and telltale heft, and concluded instead that it was made of stone. But such determinations are rarely this easy. "Often we'll see bushmeat smuggled at the bottom of a cargo shipment of smoked fish," Bessey said. "Sometimes the meat is hacked up into such small pieces that you can't tell what species was killed."

Suffering For Fashion

Artisans use crocodile, lizard and snake species with softer scales to make handbags and belts.Courtesy of Mitch Eaton

Just 10 Fish and Wildlife inspectors cover all of JFK airport, and only 100 such inspectors serve the whole country, but they have managed to gather an impressive collection of specimens. When I stopped by the agency's office, Paul Cerniglia, a supervisory inspector, led me to a tidy room where inspectors keep hundreds of seized animal products "on file" to help them identify suspect goods. He opened one cabinet full of reptile-skin handbags and then another of caviar tins and ivory statuettes. A nearby wardrobe was hung neatly with furs and skins, and on a stainless-steel shelf an elephant-foot stool was topped with a zebra-hide cushion. "If it can be made, it's here," Cerniglia said.

The trade in protected species is lucrative. According to a 2008 Congressional report, the global black market may be worth more than $20 billion a year. Cerniglia pointed at a shelf of mounted birds, tortoises and antlers. "Those trophies are worth $35,000 each," he said. A pound of rhino horn, which practitioners of traditional Chinese medicine prescribe for fever, gout and other maladies, can fetch $22,000. Yet perpetrators are seldom caught and rarely punished. In the U.S., Cerniglia said, inspectors typically confiscate violators' items and exact no further penalty. The Fish and Wildlife Service prosecutes just 10,000 violations annually, and most cases are settled before trial. Other countries demonstrate even less concern. In one case in 2006, Japanese customs officers confiscated 5,310 pounds of elephant ivory. The smuggler, who claimed that the ivory was "artificial marble," was fined the equivalent of $7,500, less than one tenth of 1 percent of the ivory's market value.

Extracting a Sample

Advanced methods can extract DNA samples from tanned and heaviy processed skins.John B. Carnett

DNA evidence can lead to tougher penalties. Today, Fish and Wildlife inspectors at U.S. ports send detained caviar samples to the Ashland lab for DNA confirmation. In one case, customs officers inspecting tins packed among a shipment of dried fish discovered 1,700 pounds of roe. Scientists later traced the roe to three species of Caspian sturgeon, putting the shipment's value at $2.5 million. A judge sentenced the perpetrator, a Russian exporter, to 27 months in prison. Since DNA testing, says John Sellar, the chief of enforcement assistance at CITES, "most of the caviar criminals said, 'Forget the U.S. as a market anymore.'"

Yet wildlife laws are becoming more complex, and so too must the DNA tests that enforce them. A portable device to identify species will help, but the bigger challenge for scientists is determining the geographic origin of a species. An animal in one area of the world may be protected, while the same species living in another part of the world may not. "We have more and more laws on the books, especially those that protect specific populations," Cerniglia said as he locked the fur wardrobe. "That's the direction we need the DNA to go in: beyond species and subspecies — local populations."

3. Prevention

To better understand how scientists are attempting to trace contraband animal products back to their source, I invited Kolokotronis to another meal, this time with more guests. Joining us would be Demian Chapman, a geneticist at the Institute for Ocean Conservation Science at Stony Brook University, and his wife, Debra Abercrombie, a fisheries consultant. We met at Congee Bowery, one of the dozens of restaurants in Manhattan that serve sharkfin soup. As we crowded around a table, Chapman explained that demand for the soup threatens several dozen of the more than 400 species of sharks, which, like bluefin tuna, remain largely unprotected. Regulating the industry, he said, requires legislation at the source—where the sharks are pulled out of the water. "The problem with the shark-fin trade is that so many different countries are participating," Chapman said, picking up his menu. "Anyone can do whatever they want. It's a Wild West show."

Glancing around the dining room, I spotted a stuffed deer and a net bulging with plastic fish. On display inside a clear case was a pair of dried, bone-colored shark fins the size of banquet platters. "Those are probably worth 15 grand," Chapman said. Abercrombie identified them in seconds: "basking shark."

Sergios-Orestis Kolokotronis and George Amato extracting DNA from sushi samples

John B. Carnett

We ordered a $40 bowl of "Braised Supreme Shark Fin in Broth." Shark fin is mostly cartilage, which swells and separates into needle-like strands when cooked. Finding usable DNA in hot soup would be challenging. The main genetic marker for species identification, which scientists refer to as a DNA barcode, is only 650 nucleotides long, and cooking can break that marker into even shorter fragments. Chapman and Kolokotronis were eager to see if their techniques were good enough to isolate the DNA from such heavily degraded samples. Kolokotronis transferred a limp fin sample into a baggie as I gingerly tried a few spoonfuls. The needles were almost crunchy. "I just don't see the hype," Kolokotronis said after he nibbled a piece. I offered a taste to the shark scientists, who had ordered the General Tso's chicken instead, and they politely declined.

As we picked at our fins, Chapman explained his method for pinpointing shark origins. Every species has a unique DNA barcode, but other genetic markers can reveal regional variations—the genetic equivalent of a ZIP code. Step one was to perfect a test that could identify the species, even in fins that had been cut, dried, and boiled. Step two was to identify the shark's genetic ZIP code. And the final step—a multiyear endeavor— was to develop a DNA database of sharks in the wild, a map whereby scientists could compare sample data against known regional characteristics and make a determination. Accurate geographic data could help authorities intercept the hunters and ensure that trade in certain regions was sustainable.

Shark Expert Demian Chapman

John B. Carnett

Owing to the remarkable breakthrough of one of Chapman's colleagues, a fisheries scientist named Shelley Clarke, the technique has already given scientists a better picture of the market for shark fins. In 2001, when Clarke was living in Hong Kong near the fish market that sold more than half of the world's shark fins, she convinced the market's major shark-fin traders to let her snip nearly 600 samples of their product. ("It was amazing that I got the access that I did," she wrote in an e-mail, "given the value of the product, the fact that I didn't pay for any samples, and that the shark-fin traders are known for being closed and secretive.")

DNA tests revealed that the majority of Clarke's shark fins derived from overfished blue shark. But Chapman said he was particularly interested in the small group identified as scalloped hammerhead shark, an endangered species that lives worldwide and is among the most prized in the fin trade. So he drilled deep into the Hong Kong samples, located their unique regional markers, and matched them to a reference map. His results showed that that one fourth of the scalloped hammerhead fins came from sharks in the western Atlantic, where ecological surveys reveal a 75 to 80 percent decline since 1972. Chapman could even specify the exact regions of the sharks' capture, such as in the Gulf of Mexico and off the coast of Brazil.

The species in my soup bowl proved to be a tougher challenge. The first step—species identification—was difficult yet doable. Chapman reported an extremely weak DNA signal, and Kolokotronis had to run his procedure several times, but both scientists produced the same results: Prionace glauca, the near-threatened blue shark. Unfortunately, the last two steps necessary to determine P. glauca's geographic origin are not yet possible. Scientists have only just begun to establish a DNA reference map for blue shark. "Since blue sharks are highly mobile, finding distinguishing markers for populations is much more challenging than for hammerheads," Chapman says.

The reference maps for sharks need more time, but geographic tracing is already exposing countries that are lax about protecting other rare animals from trade, and in some cases the technique is even helping authorities arrest poachers. Scientists at the University of Washington's Center for Conservation Biology are using geographic tracing to track massive ivory seizures back to where the elephants were killed. They were able to show, for instance, that a 2002 seizure of 532 large tusks and 42,000 hankos (ivory seals used in China and Japan) came from protected elephants in Zambia, Mozambique and Angola. The group also found that 1,094 tusks seized in Taiwan and Hong Kong in 2006 were poached from game reserves in
Tanzania and Mozambique. The findings have already enabled multiple prosecutions, including the 2009 arrest of six officials from Tanzanian customs who accepted bribes from the smugglers.

Inspecting The Evidence

Samuel Wasser examines a piece of ivory cut from the base of the elephant's trunk.Courtesy of Samuel K. Wasser

Biologist Samuel Wasser, the center's director, says that such "preventative forensics" techniques are allowing authorities to not only track the methods of a sophisticated organized trade but also to focus scarce anti-poaching resources across a vast continent. "We try to get the data to allow law enforcement to be in the right place and at right time," he says, "so they can get the evidence they need to convict poachers and dealers."

New forensic tools are also helping to preserve existing protections for elephants. At the CITES conference in March, representatives from Zambia and Tanzania petitioned to suspend the 1989 elephant-trade ban in order to sell off national stockpiles of ivory. Wasser presented his DNA-derived geographic data that seriously challenged the representatives' assertions that their elephants were safe from poaching. CITES voted to uphold the ban.

But shark conservationists were less successful at CITES this year. The representatives narrowly rejected a proposal to regulate scalloped hammerheads and other species with lookalike fins. China and Japan led the dissent, Chapman says, arguing that the fins are difficult to tell apart, despite the recent advances.

He acknowledges that genetic data alone can't solve the demand problem. "The technology is not the limitation," he says. "The barrier is the political will to actually impose the policies that would allow more sampling in the wholesale markets and regulation of fisheries. We have the tools to build the house, but in reality, we don't have the building permit."

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