CSI in Sharks: Using Genetics to Sniff Out Illegal Trade
June 19, 2009
by Sze Chun Chan
“Does it smell fishy in here?,” a student remarks as he walks into the room.
Dr. Demian Chapman places dried shark fins on the table. He was speaking to a group of school faculty and students at the Stony Brook University (SBU) School of Marine and Atmospheric Sciences. Dr. Chapman is a marine biologist with SBU’s Institute for Ocean Conservation Science, and something of a CSI investigator for the world’s oceans. Today, he brought in shark fins (the source of the odor) to drive home his point that shark populations face serious threats from humans. Rather than examining hair samples and fingerprints, Dr. Chapman gets his clues by performing molecular-level analyses of shark fins from around the world. Among his goals: to ensure that when legally protected sharks are exploited, that exploitation is detected and ultimately prosecuted.
Sharks play a vital role as the ocean’s top predators, keeping marine ecosystems healthy and in balance by managing populations of animals they eat, such as seals and stingrays. That predation in turn keeps the populations of lower-tier marine creatures in check. But shark populations globally are being devastated by the demand for shark fin soup, Dr. Chapman tells the students from the Research Experience for Undergraduates (REU) program, a 9-week program funded by the National Science Foundation at SBU and institutions nationwide. The soup was once reserved for Chinese emperors and now sells for $100 a bowl and extremely popular in Asian markets. The trade of shark fins is a multi-million-dollar industry, and obtaining those fins often involves slicing the fins off the shark and discarding the carcass.
“Combine that with global warming, and it’s a one-two knockout punch.” Dr. Chapman says of shark finning. “The perfect storm.”
Though sharks have evolved for 400 million years and have sharp teeth, huge jaws, and a keen sense of smell, not even those protective qualities can save them from the onslaught of modern fishing fleets. As a marine biologist and genetics specialist, Dr. Chapman’s pen against this indomitable sword is DNA analysis, the same tool that today help to put the guilty behind bars. In the same way DNA is used to definitively identify humans, it is also used to identify animal species – in this case, sharks.
Though many often think of sharks as frightening, they are much more often victims at the hands of humans., says Dr. Chapman, who is also an assistant professor in the SBU School of Marine and Atmospheric Sciences. “But why these animals? Why should we care?”
With that, Dr. Chapman plays a clip of underwater footage from one of his study sites in Bimini, Bahamas. The video is of an adult Lemon Shark giving birth. At 15 years old, the shark has just reached sexual maturity and this is her first pregnancy. The mother looks docile as a miniature pup flails beneath her in its first fits of life, trying to sever its umbilical cord and swim freely. A baby shark is already highly developed and fully functional at birth. The shark pup is keen to hunt the second it is born.
“There’s a take-home message from this video,” Dr. Chapman says. Sharks mature late in life and generally have few pups per litter making them especially vulnerable to heavy fishing pressure.
After the video, Dr. Chapman suddenly flings in front of the surprised students two dried shark fins. The students pass the fins around, holding and examining them. Anywhere from low as twenty-three to high as seventy million sharks are killed for shark fin soup a year, Dr. Chapman says citing a Clarke et al, 2006 study. Hong Kong is a significant center of trade worldwide with major suppliers from Europe, Taiwan, Indonesia, Singapore, United Arab Emirates, the United States, Japan, Yemen, Mexico, and India. Demand continues to grow as China modernizes. Shark fin soup that was reserved twenty years ago for the super-rich as a status symbol is becoming more accessible to the emerging middle-class. That fuels the need for increasingly more fins, and leads some fishermen to exploit government-protected shark species that are classified as threatened or endangered.
The first shark fin “crime scene” that Dr. Chapman investigated came as a result of a phone call from the U.S. Fish and Wildlife Service. According to Chapman, authorities had raided a massive seafood warehouse in Brooklyn belonging to one of the biggest shark fin traders in the Northeastern U.S., and a peculiar looking sack of shark fins got their attention. The sack was labeled “BLANCO,” which aroused the agents’ suspicion. Shark fin trading isn’t illegal, but the trading of Great White Shark fins is. Agents saw the potential of utilizing Dr. Chapman’s research techniques to investigate this lead and tracked him down.
Dr. Chapman took the suspicious sack and its content of 21 fins back to Nova Southeastern University in Florida, where he was based at the time, to conduct DNA analysis. His findings were troubling, as all 21 fins were from Great Whites, with 18 coming from young sharks. A $250,000 fine was eventually assessed against the dealer.
With further analysis, it was determined that most of the fins came from sharks caught off the Northeastern Atlantic Ocean. With an 80 to 90% population decline of Great Whites in the last few decades, this was a very disturbing find. Just months prior, wildlife law enforcement agencies had no way to distinguish shark species through only their fins. For this reason, the Convention on International Trade in Endangered Species (CITES) did not list Great Whites as a legally protected species during its meeting in 2000. Based upon the findings uncovered with Dr. Chapman’s DNA analyses, CITES added the Great White Shark to the protected species list in 2004.
Not all shark fins are of equal value. The fins of certain shark species are tastier and thus more valuable than others to dealers. In Hong Kong, one of the most valued shark fins comes from the Scalloped Hammerhead Shark. It sells for $120 USD a kilogram. Shelley Clarke, an associate of Dr. Chapman and long time Asia resident who is fluent in Mandarin Chinese, brought back 59 fins from 11 traders in Hong Kong. Dr. Chapman’s DNA analysis found that more than 25% of the fins came from sharks in the endangered North Atlantic genetic stock.
According to Dr. Chapman’s research, there are three genetic families or “haplotypes” of the Scalloped Hammerhead. Haplotype A is usually found in the North Atlantic region, B in the Caribbean, and C off the coast of Brazil. These three groups do not intermix genetic material by mating with sharks from other groups, and thus, they’re genetically distinct. If one of these haplotypes were to be severely threatened, there won’t be other genetically similar sharks to rebuild their stocks. “If we decide to protect these species, we can give law enforcement a tool to punish illegal trade,” Dr. Chapman says. “Now laws have some bite instead of being just on paper.”
Fisherman now are netting even the sharks that didn’t seem tasty or valuable only decades ago, just to have a continuing supply of fins in the face of dwindling “desired” species and an insatiable demand from Asia. In Belize, a Caribbean island where Dr. Chapman has worked for more than a decade, fishermen nowadays have a tendency to kill any shark with a fin to sell to Chinese middlemen who earn ample profits with little trade restrictions. Even the U.S. Fish and Wildlife Service seldom stops fin shipments abroad.
“The trigger has to be something else, some other reasons to be suspicious,” Dr. Chapman says. A suspicion, like the instance of a smuggler of shark fins filled with cocaine, whom the feds did stop. “If it’s just business as usual, they’re not going to check.”
Dr. Chapman says because most shark-finning remains legal, and shark fin soup is so popular, monitoring the trade and reversing demand for shark fin soip is definitely an uphill battle. But he does see glimmers of hope for his beloved animals, such as the participation by U.S. basketball star Yao Ming in efforts to educate people in his native China about how devastating this soup is to global shark populations.
“I met Yao Ming doing an anti-shark fin campaign in China,” Dr. Chapman concludes. “Many Chinese still don’t know that sharks are unique and aren’t like other fish.”
Sze Chun (J.C.) Chan is a Summer 2009 intern in the Communications Office of the Institute for Ocean Conservation Science.