The tradition of buying paper-wrapped battered fish and fried chips is deep-rooted in Australian cuisine. Flake, a generic term used to describe shark meat filets, is also a popular option. But most of the flake sold in Australia isn’t what it should be.

“Only 27% of all samples were identified as gummy shark, a species that has a sustainable population, and is one of only two species that is recommended to be labeled as flake in Australia,” said first author Ashleigh Sharrad, a researcher from the University of Adelaide’s School of Biological Sciences.

Something fishy

Mislabeling seafood is not a new problem, and it’s not a small one either. It’s happening on a vast, global scale, and it happens pretty much everywhere where fish is sold. Recent reports found that mislabeling can be as high as 70% for some species of fish.

Mislabeled seafood can pose various concerns to consumers. A small risk would be eating a fish with a different nutritional content than what you think you’re buying, but on the worse part of the scale, mislabeled seafood can be toxic and dangerous, particularly for pregnant women and those who are allergic. But there are also risks to seafood.

“Food fraud in the seafood industry is a growing concern and mislabelling may occur. It can have potential implications on human health, the economy, and species conservation,” said the University of Adelaide’s Professor Bronwyn Gillanders, a researcher in the School of Biological Sciences and the Environment Institute.

In the new study, the researchers looked at the DNA of filets from more than 100 retailers across Adelaide and regional areas of South Australia. All samples were commercially available to the general public; most were collected as a consumer would purchase from retail fish and chip shops, while a minority were bought in bulk.

They encountered the DNA of 9 different species, although only two species are meant to be in ‘flake’. Out of them, four were threatened species, including the smooth hammerhead shark and the short-fin mako shark.

Researchers suspect that it’s not the small retailers’ fault, as they probably have no idea what they purchase in bulk either. Instead, the parties that sell the retailers the product are likely at blame.

“Our results highlight the need for clearer national guidelines or labeling laws for shark fillets,” said Sharrad. “This is the key to building trust across the supply chain, boosting demand for local, sustainable catch and importantly, empowering consumers and retailers to make informed choices.”

The sale of shark meat is particularly difficult to monitor because people are very unlikely to tell the taste apart and different countries and companies use an array of ambiguous trade labels — umbrella terms that make confusion and mislabeling more likely (‘flake’ is a good example). In addition to conservation issues, this also has the potential to pose risks to human health, as some species of sharks are more prone to the bioaccumulation of heavy metals.