A group of researchers from the University of Adelaide found that up to four endangered shark species were used in the nets, including the shortfin mako shark and the smooth hammerhead shark.
The team set out to find out what type of fish was being sold as flakes – a term used to describe fillets of shark meat.
They analyzed the DNA of fillets sold at more than 100 fish and chip retailers in Adelaide and parts of South Australia and published their results in a journal called Food Control.
University of Adelaide School of Biological Sciences researcher Ashleigh Sharrad said only 27% of the samples were gummy sharks.
“The gummy shark is a species that has a sustainable population and is one of only two species recommended for flake tagging in Australia,” Ms Sharrad said.
A total of nine different species types were found in the nets, some of which are not found in Australian waters.
The research found that only one in 10 retailers correctly identified the type of fish being sold, while 20% were completely mislabeled.
The remaining 70% had ambiguous labeling, the study found.
Professor Bronwyn Gillanders said “food fraud” in the seafood industry is a growing concern.
“This may have potential implications for human health, economics and species conservation,” Professor Gillanders said.
Ms Sharrad said smaller retailers could not be accused of mislabeling the flake fillets because they would not know what was in them when buying bulk, processed or frozen products.
The Australian Fish Names Standard recommends that the term flake be used only to describe the gummy shark and New Zealand rig, but the guideline is not mandatory.
“Our findings underscore the need for clearer national guidelines or labeling laws for shark fillets,” Sharrad said.
“It’s key to building trust throughout the supply chain, driving demand for local and sustainable catches and, most importantly, empowering consumers and retailers to make informed choices.”