Something’s fishy: 1 in 5 seafood products are mislabelled, study finds

The fish advertised at a seafood counter or on a sushi restaurant's menu might not be the same one that ends up in your shopping bag or on your plate, a Calgary study warns.

One of every five pieces of seafood bought from a Calgary restaurant or grocer was mislabelled at best or an entirely different species than what was claimed on the packaging, a new study published Monday finds.

The latest study in what’s been a long-identified trend across Canada has major implications for consumers’ health and wallets, as well as for the protection of endangered species, one of the study’s authors tells Global News.

“There’s no way for you as the consumer to have any idea if what you bought is what you got when you’re buying sushi. And that’s just the sad reality of it right now,” says Matthew Morris, associate professor of biology at Ambrose University in Calgary.

The problem is wider than your favourite all-you-can-eat sushi joint, according to the study published Monday in PeerJ’s biodiversity and conservation journal.

Students from Ambrose, which describes itself as a private Christian liberal arts university, worked with peers at Mount Royal University and the University of Calgary between 2014 and 2020 to sample a variety of seafood at grocers and restaurants in the city and cross reference their “DNA barcode” with what was on the label.

The results found that roughly one in five products were mislabelled to the point where the wrong species was substituted for what was sold. That includes both invertebrates such as shrimp, oysters and octopus as well as finfish like cod or salmon.

Misidentification rates were slightly higher, around one in three, when “semantic mislabelling” was included — a broader classification where an inaccurate label was used on something like “freshwater eel,” but consumers were likely still getting some form of eel.

But Morris explains that the most egregious instances are when a student purchased a cut of Atlantic salmon, only to find they had received rainbow trout that was manipulated to give its flesh the same pink colour as salmon.