Scientific Detective Work: Tracking Shark Fins Around The Globe

Scientific Detective Work: Tracking Shark Fins Around The Globe

Melissa Cristina Márquez | Oct 21, 2020,07:53pm EDT

Donning their detective hats, scientists Florida International University scientists Dr. Demian Chapman and Dr. Diego Cardeñosa are protecting living shark populations by letting the dead speak.  

While pelagic thresher sharks are considered a single species, there are actually two “clades” or separate populations that exist. These groups don’t intermingle. Instead, they mate within their specific clade. This means there are two different genetic populations — a Western group that resides in the ocean between Taiwan and Hawaii and an Eastern group, which roams between Hawaii eastward toward the coast of the U.S., Mexico, Costa Rica and Ecuador. The majority of the samples tested were from sharks that had belonged to the Eastern group. GETTY

More specifically, gathering clues from shark fins found in retail markets in China and Hong Kong. Collaborating with researchers in Hong Kong to track and monitor the global shark fin trade using DNA testing, the detective work was able to trace where sharks were initially caught. The results are grim: almost 85 percent of fins sampled in these markets were genetically traced back to the Eastern Pacific.

“The findings weren’t surprising, because earlier this year we discovered the majority of fins from endangered scalloped hammerhead sharks also originated from the Eastern Pacific,” Cardeñosa said. “This is a region with poor fisheries management and poor capacity to enforce international regulations.”

Cardeñosa is right – this isn’t the first time fins from endangered sharks have been linked to this specific area. The Eastern Pacific not only attracts tourists from around the world to take advantage of the multitude of marine habitats in this region, but it has also gotten the interest of industrial fishing fleets. The growing presence of Chinese industrial fishing vessels just off the Galápagos Islands made international news as journalists reported on the “discovery” of this “massive” fishing armada of Chinese fishing vessels which fluctuated to over 350 ships before the they left by mid-October to fish farther south.

Inhabitants of Santa Cruz Island in Galapagos, Ecuador, took to the streets to protest against illegal fishing around the islands in 2017 after the Ecuadorian Navy reported that a Chinese-flagged ship in the Galapagos Islands with hundreds of rare, endangered, and close-to-extinction animals that include at least two species of shark considered vulnerable by the authorities of the country. The recent FIU findings have pinpointed the Eastern Pacific as a major supply chain starting point for thresher sharks and other threatened sharks — and also a high-risk region for illegal trade. It also shows where conservation interventions are needed. This has particular relevance for the USA, as well, because many fins come through USA ports on their way to Hong Kong. We play a role in trade — and our border control personnel are in need of tools to help them detect possible illegal trade. AFP VIA GETTY IMAGES

The public (and scientists) is right to worry about the illegal, unreported, and unregulated (IUU) fishing that can and does go on in these sort of fishing fleets. One of the largest arrests over IUU fishing was back in 2017 when the Chinese-flagged veesel FU YUAN YU LENG 999 was found in the Galápagos with about 3,000 tons of endangered species onboard in their freezers, including roughly 600 sharks. And earlier this year in Hong Kong, customs officials intercepted an illegal shipment from Ecuador that contained 26 tons of thresher shark fins.

Thresher sharks, famous for their whip-like tails, are protected under Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This means that in order to trade these sharks, the sellers must have permits certifying the animals were legally caught and are traceable through the supply chain. Since 2017, CITES permits have documented more than five tons of shark fins exported from the Eastern Pacific to Hong Kong. But that only capture the legal trade operations, not the illegal trade happening right alongside it.

The secret tool behind this recent historic seizure of shark fins was a DNA testing kit co-developed by Dr. Chapman and Dr. Cardeñosa. So, this type of genetic testing works. And that is why the researchers are so sure the clues left behind the tested fin trimmings are leading them back the scene of so many maritime fishing crimes: the Eastern Pacific. “Our research pinpoints the Eastern Pacific as a major supply chain starting point for thresher sharks and other threatened sharks, and also a high-risk region for illegal trade,” Cardeñosa said. “With what we know, we can begin to guide intervention efforts to monitor and enforce international laws. It’s especially important to use all available technology and tools to detect and deter illegal trade of CITES-listed species.” 

PUERTO LOPEZ, ECUADOR – APRIL 6: A dead thresher shark lies on the beach on 6 April 2012 in Puerto Lopez, Ecuador. Every morning, hundreds of shark bodies and thousands of shark fins are sold on the Pacific coast of Ecuador. Although the targeted shark fishing remains illegal, the presidential decree allows free trade of shark fins from accidental by-catch. However, most of the shark species fished in Ecuadorean waters are considered as “vulnerable to extinction” by the World Conservation Union (IUCN). Although fishing sharks barely sustain the livelihoods of many poor fishermen on Ecuadorean at the end of the shark fins business chain in Hong Kong they are sold as the most expensive seafood item in the world. The shark fins are primarily exported to China where the shark’s fin soup is believed to boost sexual potency and increase vitality. Rapid economic growth across Asia in recent years has dramatically increased demand for the shark fins and has put many shark species populations on the road to extinction. (Photo by Jan Sochor/Latincontent/Getty Images) LATINCONTENT VIA GETTY IMAGES

Cardeñosa and Chapman are committed to combating illegal trade with their DNA detective work. Their testing kit was created with funding from the Paul G. Allen Family Foundation, and it’s being used in airports and shipping ports to help customs officials identify protected shark species. But why there and not solely at the markets? “There is a tendency for people to focus on the fin markets when looking for solutions to this problem, but our work shines light on the regions where most fins are coming from and hence where shark conservation and fisheries management could make a real difference on the ground,” Chapman explained. “We will only progress on global shark conservation by working throughout the supply chain — from ocean to markets.”

Informing and sharing news on marine life, flora, fauna and conservation in the Galápagos Islands since 2017
© SOS Galápagos, 2021

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