Ban the cut and the market follows. That has been the working assumption behind shark-finning regulations for twenty years, and a new analysis cannot find evidence for it.
An interdisciplinary team led by UC Santa Barbara, with The Nature Conservancy and Renmin University of China, tested finning rules against actual trade flows. Writing in Nature Communications, they report no statistically significant effect on exports, imports, domestic consumption or the number of trading partners.
"We evaluated a lot of different things and found that there's really no clear-cut answer to our research question," said co-lead author Echelle Burns, a project scientist at UC Santa Barbara's Environmental Markets Lab.
The study exists at all because of a data problem that was only recently solved. Landings data and trade data are kept separately, in different units, so following a shark from the water to a market stall was effectively impossible. The Aquatic Resource Trade in Species dataset, released by the University of Washington in 2024, tracks fishery products through trade networks and closed the gap.
"This research highlights the complex dynamics between fishing practices and trade," said co-lead author Sara Orofino, an ocean scientist at The Nature Conservancy, noting the two had always been studied as separate systems.
The design compared each country against its own pre- and post-regulation record, then compared those differences across countries, with unregulated nations as a control. Two competing predictions were on the table. Burns set out the optimistic one: "One idea is that if we prevent shark finning, and fishers decide to stop targeting sharks, then maybe the market for shark products will shrink." Co-lead author Kaiwen Wang, an economist at Renmin University of China, set out the pessimistic one: "For example, if a country requires that fishing vessels must land sharks with their fins still attached, the influx of shark meat supply could stimulate a market expansion for shark products."
The data supported neither.
Senior author Gavin McDonald of UCSB's Environmental Markets Lab defended publishing a negative finding. "This sort of null result can initially be disappointing for us as researchers," he said. "But it is still incredibly important to share these types of findings. All too often, analyses with null results are abandoned and not shared or published, which can be a huge missed opportunity for advancing science and policy." Wang put it more bluntly: "Our findings are an important warning that real-world changes along the supply chain of shark products are much more complicated than we would have thought."
That pushes the question toward enforcement -- where a separate line of research has already produced hard evidence. A Science Advances study led by Dr Diego Cardenosa of Florida International University alongside Dr Demian Chapman of Mote Marine Laboratory DNA-tested close to 20,000 shark fin samples taken from Hong Kong markets between 2014 and 2021. Four of the five species given CITES protection in 2013 -- scalloped, smooth and great hammerheads, plus oceanic whitetip -- appeared consistently, despite almost no certified legal trade being declared.
"There's a huge gap between what's on paper and what's happening in the real world," Cardenosa said. "DNA evidence clearly shows these protected species are still entering the global market at alarming rates. There are 70 times more fins from oceanic whitetips and 10 times as many hammerhead fins than would be expected based on legal and certified reporting."
Eighty-one percent of fin-exporting countries have never reported trade in the listed species. Genetic tracing followed scalloped hammerhead fins back to six ocean regions, three with no legal export records at all.
"Our findings show that while global trade regulations are a powerful tool, their effectiveness depends on countries actually enforcing them," Chapman said. "We're seeing clear evidence of widespread noncompliance, illegal trade is still happening on a massive scale."
The two results answer different halves of the same question. Rules governing how a shark is cut up did not shift the market. Rules governing what may cross a border are being broken at volume. Between them sits a patchwork of finning bans, retention bans, gear restrictions and trade listings that looks far more formidable on paper than it performs in practice.
The biology is the constraint nobody can legislate around. Sharks grow slowly, mature late and have few young. "Many shark species face extinction because they're frequently caught by fisheries -- sometimes on purpose and sometimes [by] accident," Burns said. Cardenosa's assessment was starker: "We are reaching a major tipping point where if the fishing and trade of these species is not meaningfully reduced, then these sharks will disappear."
