11 January 2006

Genetic test reveals illegal international trade in great white shark fins

Law enforcement agents are using a genetic test — similar to those used by investigators in popular television programs — to identify fins and other products from the highly protected Great White Shark, according to an article published in the journal Conservation Genetics.

Resembling the story line of a prime time plot, in late 2003 agents from the National Oceanic and Atmospheric Administration confiscated approximately 1 ton of dried shark fins intended for export to Asian markets from a U.S. East Coast seafood dealer. One of the confiscated sacks was labeled "porbeagle," a close cousin of the Great White Shark, but a label concealed inside read "blanco," which is Spanish for "white."

With the help of the agents, scientists from the Guy Harvey Research Institute (GHRI) at Nova Southeastern University (NSU) in Florida, took small samples from each of the 21 sets of fins for DNA analysis using a novel, rapid method utilizing both nuclear and mitochondrial markers.

"All 21 suspect fins yielded the unambiguous, white shark diagnostic pair of DNA amplicons, a type of DNA fingerprint confirming the origin of the species," says Mahmood Shivji, Ph.D., principal study author and director of the Guy Harvey Research Institute.

Using the forensic assay they developed earlier, Professor Shivji and his graduate students have found white shark species-specific primers that generate a distinctive pair of amplicons, which are unique to white sharks, in their small lab at the mouth of busy Port Everglades just south of Fort Lauderdale.

"Dr. Shivji and his graduate students have been very helpful to us in more than a dozen cases," says Paul Raymond, special agent with the NOAA Office of Law Enforcement. "Shark species identification is one of the hardest things to deal with in terms of fins and shark meat."

Agent Raymond is not able to provide further details on the pending case, as it has not yet gone to trial. The penalty for possessing or selling prohibited shark species includes fines up to $100,000.

The Great White Shark, a long-time protected species in the United States, was listed last year in the Appendix II of the Convention for the International Trade of Endangered Species (CITES), helping to ensure that international trade does not compromise or harm wild populations.

"The existence of this DNA test is one of the key reasons that the Great White Shark received international protection under CITES," says Ellen Pikitch, Ph.D., executive director of the University of Miami's Pew Institute for Ocean Science (PIOS) and a co-author of the study. "The discovery of multiple fin sets from this high-profile, species found through application of the DNA test demonstrates that surreptitious exploitation of protected sharks is occurring in the U.S. Atlantic - a region with among the most extensive shark fishing regulations in the world."

As apex predators, Great White Sharks are naturally rare. And because they are slow to mature and produce few young, sharks are exceptionally vulnerable to overfishing and slow to recover from depletion. The female Great White Shark matures at age 12 and produces an average of 5 young at a time. Highly prized shark parts are traded internationally — a set of jaws may sell for tens of thousands of dollars. Shark fins are a delicacy among certain Asian populations, as a bowl of its clear broth may fetch $150.

"The discovery of so many smaller shark fins from a highly protected species in the possession of a single trader indicates that there may be a specialized market for white shark fins not only as trophies but also as food, putting additional pressure on the species," says Professor Shivji. "By applying DNA techniques to track the species of origin of shark fins in the market, we can put 'teeth' into enforcement of fishing regulations and finally begin to assess the impacts that trade poses to the health of shark populations. In turn, this knowledge will help in conservation planning and fisheries management for white sharks and other declining shark species."

Source: www.sharktrust.org


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