DNA probe uncovers threatened shark species in Thailand’s markets

  • A shark DNA investigation has revealed the presence of shark species threatened with extinction in products commonly sold in Thailand’s markets.
  • The study identified products derived from 15 shark species, more than a third of which have never been recorded in Thai waters, highlighting the scale of the international shark trade.
  • Marine conservation groups say the findings underscore that consumers of shark fin soup and other shark products could well be complicit in the demise of threatened species that fulfill vital roles in maintaining ocean balance.
  • Experts have called on Thai policymakers to improve traceability in shark trade supply chains, expand marine protected areas, and make greater investments in marine research.

Shark conservation groups in Thailand are calling for greater marine protections and improved traceability in shark trade supply chains following a study that identified threatened shark species in products commonly sold in the country’s markets.

The DNA-based study detected 15 shark species in products sampled from retail markets, restaurants, warehouses, seaports and fish landing sites around Thailand. More than half were species listed as threatened with extinction (vulnerable, endangered or critically endangered) on the IUCN Red List, including great hammerheads (Sphyrna mokarran), scalloped hammerheads (Sphyrna lewini) and sandbar sharks (Carcharhinus plumbeus).

The research team, comprising Thailand’s Department of Fisheries, wildlife advocacy group WildAid and Thailand-based researchers, published their findings last year in Conservation Genetics. In a new report highlighting the implications of the findings, WildAid points to shortcomings with traceability in the international shark fin trade and urges the public to say “no” to shark fin and other shark-derived products.

“What we discovered was probably just the tip of an iceberg,” Petch Manopawitr, a conservation scientist and Thailand program adviser at WildAid, told Mongabay. Given the shark fin trade is notoriously opaque and difficult to monitor, Petch said there’s currently no means of reliably tracing where the sharks identified in the study came from, how they were caught, or by whom.

What is clear, however, is that consumers of shark products, such as shark fin soup, are risking complicity in the demise of keystone species that could have knock-on consequences for the health of the world’s oceans. “To put it in perspective, it is no different from us consuming tigers or even tiger cubs, which is another species crucial to maintaining the balance of the ecosystem,” Petch said.

Shark fins
Many of the fins sampled in the study were very small, likely from juvenile sharks. Image by Pimpakarn Laongdee for WildAid.

Despite their vital role as the ocean’s top predators, shark populations have been decimated the world over by overfishing, bycatch and consumer demand for their fins, driving more than one-third of all shark and ray species toward a risk of extinction. Thailand claims to have no targeted shark fisheries and that all of the country’s shark haul is classified as bycatch: incidentally caught by vessels fishing for other species, such as tuna.

While shark finning isn’t banned by law in Thailand, it’s not as prevalent as it once was, according to Sirachai Arunrugstichai, a marine scientist, photojournalist and co-author of the study. “Fins are commonly sourced from sharks that were landed whole after being caught [as bycatch] in industrial fishing gear.”

Notwithstanding the reduced incidence of shark finning, experts have raised concerns that landing whole shark carcasses instead may still incentivize catching sharks by creating additional markets for shark meat, cartilage and other body parts.

Shark fin
Shark fin is commonly found in markets in downtown Bangkok. Image by Bruno Gonzalez.

Significant trade and consumption

Thailand is one of the world’s top exporters of shark products. According to a 2015 report by the U.N. Food and Agriculture Organization (FAO) on the status of the global market for shark products, the Southeast Asian nation specializes in low-quality, often small-sized shark fins. Between 2012 and 2016, Thailand shipped 22,466 metric tons of shark-derived goods overseas, making it the No. 1 exporter globally during that period.

Now, the new findings suggest that despite heightened consumer awareness of the implicit risks of killing sharks to the health of marine ecosystems, the country is also a major market for shark-derived products. Recent surveys of Thailand’s urban population, carried out by WildAid, indicated more than half of respondents intended to consume shark fin in the future. While this figure is lower than in previous surveys, it’s still alarming for conservationists.

“It’s discouraging to see that people are still continuing to consume shark,” Petch said. “The message about shark fin and endangered species has been communicated for such a long time. [People who continue to consume sharks] are either totally ignorant, or just don’t care at all.”

Recent shark landing data from Thailand cover merely 60% of the diversity of species compared to hauls from one decade ago, the WildAid report says, a sign that local shark populations might be “perilously close to collapse.”

In addition to identifying threatened species in the trade, the research team were concerned to uncover a significant proportion of small shark fins, some from critically endangered species. The researchers say this indicates heavy exploitation of juvenile sharks, a practice that could severely hinder the recovery potential of impacted populations.

Shark fin analysis
A researcher prepares shark fin samples for DNA extraction and sequencing. Image by Pimpakarn Laongdee for WildAid.

More than one-third of the species identified in the study have never been recorded in Thai waters, including night sharks (Carcharhinus signatus) and dusky smooth-hounds (Mustelus canis). This hints at the magnitude and complexity of the international trade, the authors say, with imports necessary to satisfy local demand for shark products and also to sustain reexport businesses, given that Thailand is a known shark trade hub supplying markets such as Hong Kong, Taiwan and Singapore.

“Given Thailand’s important role in the international trade of shark fin, the country needs to rapidly strengthen its capability to trace the supply chain of shark fin,” the report says. New DNA techniques, like those used in the recent study, have a lot of potential both in Thailand and internationally to boost law enforcement and trade monitoring, Petch said.

Stepping up shark trade traceability would enable Thailand to keep pace with international regulations. Some 85% of the species found in the study were requiem sharks (Carcharhinidae), a family of sharks recently listed in Appendix II of CITES, the global wildlife trade convention. This makes their trade subject to strict controls. However, in a move unique among shark-trading countries, Thailand requested a six-year reservation on the new rules in order to put systems in place to monitor shark landings and trade.

Under current Thai law, whale sharks and four species of hammerhead sharks are the only shark species protected in Thai waters, with attempts to hunt, kill or trade them punishable by a prison term of up to 15 years or fines up to $42,400. However, the Thai Department of Fisheries is in the process of introducing additional protections for two further species of hammerheads alongside a national plan on the conservation and management of sharks.

“The Department of Fisheries acknowledges the crucial role of sharks,” Chalermchai Suwannarak, director-general of the Department of Fisheries, said in a statement released by WildAid. “[The department] is committed to implementing measures that effectively monitor and regulate the trade of shark species listed under CITES, ensuring the sustainable use of sharks.”

But measures and plans are only ever as good as their implementation, Petch said. “The timeline for implementation [of the national plan on sharks] is still unclear,” he said. “We need to be clear why we need strict protections in certain areas and how that is going to benefit not just shark populations, but the whole marine ecosystem. Fish stocks will be better if you have better conservation … and in Thailand we generate a lot of economy through tourism, so conservation of marine species should be a top priority.”

Shark fin for sale
Shark fin prepared for cooking in a market in Thailand. Image courtesy of WildAid.

Bycatch solutions paramount

Besides stronger legislation governing trade, ending the overexploitation of sharks depends on reducing their slaughter in the first place. Experts say that solving the problem of fisheries bycatch is paramount.

“Sharks are a reflection of how unsustainable some fishing gears are,” Petch said. “The otter trawl and the paired trawl are the top two gears that catch the most sharks … they’re so powerful, so effective that they basically pretty much catch everything.” He added that up to one-third of Thailand’s commercial fishery catch is classified as noncommercial “trash” fish, a category that includes sharks and typically ends up as animal feed.

“Pet companies have started to import the whole dry shark to give it to dogs and other pets as a snack,” Petch said. “To me it was just, you spend 20 years educating people about how bad shark fin is, and now they’re moving down the food chain to just give it to dogs as a snack. It’s really, really disappointing.”

Restrictions on the use of nonselective fishing gear like otter and paired trawls could go some way to reducing shark bycatch, Petch added, especially if such measures can be implemented in important shark conservation areas.

“Maybe increased shark protections means more seasonal fishery closures,” he said, “but it will restore ecosystem health in the long term and that is much more sustainable and profitable compared to where we are now.”

Carolyn Cowan is a staff writer for Mongabay. Follow her on 𝕏, @CarolynCowan11.

Banner image: Fins from great hammerheads and scalloped hammerheads were for sale in Thailand’s markets. This hammerhead was photographed in Japan. Image by Masayuki Agawa / Ocean Image Bank.


Klangnurak, W., Arunrugstichai, S., Manopawitr, P., & Krajangdara, T. (2023). DNA-based species identification of shark fins traded in Thai markets. Conservation Genetics, 24(4), 537-546. doi:10.1007/s10592-023-01519-0

Dulvy, N. K., Pacoureau, N., Rigby, C. L., Pollom, R. A., Jabado, R. W., Ebert, D. A., … Simpfendorfer, C. A. (2021). Overfishing drives over one-third of all sharks and rays toward a global extinction crisis. Current Biology, 31(21), 4773-4787. doi:10.1016/j.cub.2021.08.062

Worm, B., Orofino, S., Burns, E. S., D’Costa, N. G., Manir Feitosa, L., Palomares, M. L., … Bradley, D. (2024). Global shark fishing mortality still rising despite widespread regulatory change. Science, 383(6679), 225-230. doi:10.1126/science.adf8984

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