When ordering fish at a restaurant or market, you may not be getting what you think.

Using DNA barcoding technology, University of Guelph researchers have found that 25 per cent of fish are mislabelled and in a majority of the cases, the fillets are sold as species of higher values.

"This not only raises concerns of consumer fraud, but also public health," said Robert Hanner, integrative biology professor and associate director for the Canadian Barcode of Life Network, who worked on the study with masters student Eugene Wong. "A person could have allergies to a certain species and if it's mislabelled that could have dangerous consequences."

The study, set to be published next week in the journal of Food Research International, includes about 100 fish samples from restaurants and markets in Toronto, Guelph and New York City. Wong and Hanner collected samples from spots in Toronto and Guelph and the samples from New York City were collected by two high school students who accessed U of G's Barcode of Life data systems library for a school project.

The most commonly mislabelled fish was the Red Snapper. In a number of cases a fillet would be labelled as Red Snapper when it was actually another species of fish of lesser value, said Hanner.

They also found that endangered fish species were mislabelled as species that are considered to be eco-friendly.

For example, there were cases where Atlantic Halibut, a species whose stock has collapsed, was mislabelled and sold as Pacific Halibut, a species known to be harvested with effective stock management practices, he said.

"Consumers may think they are doing the right thing for the environment by buying a certain type of fish that is eco-friendly when really they could actually still be buying exploited species."

The researchers used DNA barcoding to identify the samples in the study. This technique was first proposed by U of G scientist Paul Hebert and involves extracting a short DNA sequence from a gene found in all animals.

The sequence taken from a reference specimen is analyzed and then entered into the Barcode of Life Data System, a community resource database that serve as a 'look-up table' for the identification of unknown species.

Researchers have been working to identify and catalogue species from around the world using barcode technology and so far, more than 5,000 of the approximate 30,000 species of fish have been barcoded, said Hanner, who is also the campaign coordinator for the Fish Barcode of Life initiative.

This study demonstrates that the fish barcoding library is capable of identifying fillets in the market place and can be used as an effective regulation tool, he said.

In fact, Hanner and his colleagues at U of G's Biodiversity Institute of Ontario are already working with the United States Food and Drug Administration towards validating DNA barcoding as a regulatory method for seafood authentication and they expect that Canadian regulatory agencies will follow suit.

"This study shows there are a lot of implications for DNA barcoding from authenticity testing to consumer health to conservation and resource management."

Source: University of Guelph