Thirty-four of 153 fish samples purchased by Marketplace were mislabelled. (CBC)DNA testing of a variety of fish bought at several Canadian grocery stores reveals products are sometimes mislabelled and some species being sold are endangered, an investigation by CBC-TV's Marketplace has found.

Marketplace purchased 153 pieces of fish — everything from halibut to pickerel, sea bass and shark — at big and small stores across Canada. While many stores had no labelling issues, 34 fish samples, or about 22 per cent, were mislabelled.

"Consumers are definitely being ripped off," said Robert Hanner, a biologist with the University of Guelph's Biodiversity Institute of Ontario, where the fish samples were analyzed.

Hanner is associate director for the Canadian Barcode of Life Network, a project that will allow scientists to identify all the fish in the world using genetics. Every species gets its own DNA bar code and the information is fed into a giant database, allowing scientists to find instant matches.

"Once these fillets are processed, they become very difficult to identify without these kinds of molecular methods, and so DNA bar coding has given us a very powerful tool to enact enviro-surveillance of the food chain," said Hanner.

Biologist Robert Hanner, of the University of Guelph, shows Marketplace host Erica Johnson, how they identify fish, using DNA barcodes. (CBC)Thanks to the Barcode of Life, it took little time to analyze the Marketplace samples.

For instance, salmon from a Sobeys in Toronto was labelled as Pacific salmon, specifically wild Coho and wild Red Spring. But DNA testing determined that it was actually farmed Atlantic salmon, which is about $2.20 per kilogram cheaper than the wild variety.

Many people are willing to pay more for wild salmon because farmed salmon are given antibiotics and other drugs, and subjected to pesticides, according to the website of renowned conservationist David Suzuki, who has advised against eating farmed salmon.

"Atlantic salmon is a common species in aquaculture and this is often substituted for wild Pacific salmon," said Hanner.

Testing on another piece of fish from Sobeys labelled as shark steak reveal it to be sandbar shark, a species considered "vulnerable."

There are no Canadian laws preventing fish termed "vulnerable" from being sold but Sandbar shark is not supposed to be on store shelves because it has not been approved by the Canadian Food Inspection Agency.

Sobeys said it was told differently by the CFIA about restrictions on sandbar shark. It blamed "human error" for selling farmed Atlantic salmon as wild Pacific, and said it has "put in place new processes… to prevent future occurrences."

In Montreal, "cod" was purchased from several grocery stores, including Metro, Loblaw and Provigo, for about $17.60 per kg. But testing determined some pieces were actually haddock and pollock. And while haddock costs about the same as cod, pollock goes for about $11 per kg.

Metro, where some of the mislabelled samples were bought, also blamed the labelling mistake on human error.

Loblaw working to 'ensure' fish safety

At a Loblaw in Sainte-Foy, Que., a fish sample was labelled as Pacific halibut, but testing found it to be wild Atlantic halibut, a species that conservationists consider endangered.

For its part, Loblaw offered assurance that it was working to "ensure the authenticity, safety and quality" of its fish products.

Hanner blamed the mislabelling of fish on weak legislation and lack of enforcement.

"Resource scarcity combined with, I would say, rather weak legislation that doesn't punish people who substitute one fillet for another have driven profiteering in this area — people who are engaging in food fraud," said Hanner.

The CFIA, which enforces the country's labelling laws, has promised to look into the mislabelling findings.

"The CFIA is responsible for enforcing the regulations as they currently exist," said Mary Ann Green, the head of the agency's food safety and consumer protection department.

Last year, the CFIA did not lay any charges against retailers nor wholesalers for mislabelling fish.

Green noted that the majority of samples that Marketplace tested were in compliance with the laws.

"You found a lot of compliance. Therefore there are systems in place that are working," said Green. "The majority of your products were in compliance."