Unsuspecting Australians are being duped at their local fish and chip store, as experts say threatened shark species are being sold as flake.

Researchers analysed flake fillets from more than 100 retailers, finding that only 27 per cent were identified as gummy sharks, a species that has a sustainable population and is one of only two species that is recommended to be labelled as flake in Australia.

Although the study focused on South Australia, researchers told The New Daily that the issue was likely pervasive and widespread.

“I would suspect the problem is probably more widespread because the same guidelines occur around Australia,” said the University of Adelaide’s Professor Bronwyn Gillanders, a researcher in the School of Biological Sciences and the Environment Institute.

Food fraud

“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.”

Researchers say there are health risks associated with eating certain shark species. Photo: Getty

Of all the flake samples analysed, only 10 per cent of retailers correctly identified the type of fish being sold, while 20 per cent of the fillets were mislabelled, and the remainder had ambiguous labelling.

Nine different species were identified in the study, including threatened species such as the short-fin mako shark, the smooth hammerhead shark and some not found in Australian waters.

Fillets of short-fin mako shark, a threatened species, were found in flake samples. Photo: Getty

Researchers said many fish and chip store owners were oblivious to the issue, and were probably not actively trying to deceive customers.

“Smaller retailers can’t be accused of mislabelling because they are most likely unaware when they purchase bulk, processed or frozen fish fillets,” said first author Ashleigh Sharrad, a researcher from the University of Adelaide’s School of Biological Sciences.

“We don’t know where in the supply chain things might be being picked up, switched, mislabelled or whether they’re just being put under this broad umbrella term ‘flake’,” Professor Gillanders said.

Health risks

Professor Gillanders said there were health risks associated with consuming some shark species.

“Some of the really long-lived shark species potentially also bio-accumulate things like heavy metals … so there are potentially human health issues there as well.”

Many samples and studies have found different toxins in shark meat sold in Australia, including mercury.

The effects of mercury poisoning can include blindness, loss of hair, teeth and nails, skin peeling, and kidney failure.

The Australian Fish Names Standard recommends the term flake only be used to describe gummy shark (Mustelus antarcticus) and New Zealand rig (Mustelus lenticulatus), but this guideline is not mandatory.

“Our results highlight the need for clearer national guidelines or labelling laws for shark fillets,” Ms Sharrad said.

“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.”