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Whether you're chowing down on sashimi or purchasing seafood from grocery stores in Vancouver, you may be consuming items that are not what you think they are.

A new study by UBC's food safety and health engineering lab, in partnership with Oceana Canada and the University of Guelph, has revealed that one out of every four seafood items sold in Metro Vancouver is improperly identified.

The study, led by UBC food science PhD candidate Yaxi Hu, was published today (June 18) in the international food safety and process control journal Food Control.

Researchers collected seafood samples in Metro Vancouver between September 2017 and February 2018, including from Vancouver, North Vancouver, West Vancouver, Burnaby, Richmond, Coquitlam, Surrey, and Langley.

The researchers used DNA barcoding, which involves comparing the genetic markers from test specimens with reference information to identify species. The study was one of the first to focus on the Metro Vancouver seafood market using DNA barcoding methods.

Out of 281 fish products, 70 items were found to be mislabelled.

Non-sushi restaurants had the highest rate of mislabelling at 29 percent, followed by grocery stores at 24 percent and sushi bars with 22 percent. The study notes that although the mislabelling rate in the sushi market is still unsatisfactory, the rate among Metro Vancouver sushi bars, which was the lowest of the three categories, was significantly lower than studies in Eastern Canada, the U.S., and Europe.

The most commonly mislabelled fish was snapper—31 out of 34 samples (91 percent) were mislabelled.

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Researchers found evidence of both intentional and unintentional misidentification for various reasons, including economic gain.

The study explains that although Canada is one of the world's top 10 fish exporters, due to the complexity of the food supply process, fish harvested in Canada can be processed elsewhere, such as in China or the U.S., and then sold back to Canada as a foreign product, and misidentification can occur at any stage in the supply chain.

Contributing factors to mislabelling include an inability to monitor species substitution, inability to visually identify species, removal of species-identifying features (such as head or scales), ambiguity in labelling regulations, lack of traceability, and differences in local names of fish (even between Canada and the U.S.), resulting in differences in labelling standardization.

Fish product labelling regulations in Canada do not require detailed information about the identity of the fish, such as geographic origins, if they are wild or farmed, or catching or farming methods.

“Seafood fraud cheats Canadian consumers and hurts local, honest fishers as well as chefs and seafood companies looking to buy sustainable seafood," Oceana Canada seafood fraud campaigner Julia Levin stated in a news release. "It causes health concerns and masks global human-rights abuses by creating a market for illegally caught fish. The key to fighting seafood fraud is boat-toplate traceability. This means tracking the seafood product through the supply chain and requiring that key information travels with the product.”

Food fraud, the study notes, is an international $52-billion problem. The mislabelling of some fish species can also lead to a negative impact on health. For example, the researchers point out that substituting escolar for white tuna can lead to increased consumption of indigestible wax esters in escolar, which can cause diarrhea, cramps, nausea, or headaches.

Previous studies of seafood in other locations in Canada have found similar results, and an Oceana Canada study found almost 50 percent of samples in Ottawa were mislabelled. Oceana Canada will release a national seafood report this autumn based on testing conducted in Victoria, Vancouver, Toronto, and Halifax.

The UBC–led study recommends a harmonization of the Canadian Food Inspection Agency's fish list with major trading countries, mandatory labelling with scientific names (to reduce mistranslation or confusion due to regional names), and including detailed fish identity information, including geographic location where caught or farmed, processing history, and fishing or farming methods employed.