Oceana Canada, an ocean research charity, is hoping citizen scientists in Halifax armed with DNA kits will help them sniff out seafood fraud.

The group estimates as much as 40 per cent of seafood sold in Canada is mislabelled.

"This information helps raise the public awareness and helps us take the information and the support to government to lobby and advocate for change in the regulations … to make sure that people can be confident the seafood they're getting is the seafood they're buying," Joshua Laughren, the executive director of Oceana Canada, told CBC Radio's Mainstreet.

Testing Halifax fish

Laughren said after testing in Ottawa last year, it found almost half of the fish samples were incorrectly labelled or fraudulent.

Testing has also been conducted in Vancouver and Toronto, but the results haven't come in yet. Oceana Canada is in the midst of testing fish in Halifax.

Laughren said people can help test fish in Halifax by going to Oceana Canada's website and registering for a testing kit.

"You go to a restaurant or grocery store, find the sample, make sure you record what it says it is … and you take a tiny little sample, put it in the kit, put it in the drying agent and mail it off," said Laughren.

"It's nice and simple and easy and then we take those to a lab and get it properly tested and then we summarize all the results."

Expensive fish more at risk

The organization will give some direction on the types of fish it's looking for. It won't name the restaurants and stores involved, but it would show "the level of misrepresentation."

Laughren said he's hoping to get 100 volunteers in Halifax to help with the project. He said Oceana will be getting 100 samples on its own.

"We know that some species are at a much higher risk than others — usually the expensive ones.

"Tilapia is usually tilapia because it's cheap. And you've got things like halibut and swordfish, snapper — these are things that are often not what they're labelled to be."

Illegal fishing harmful

Laughren said seafood fraud is harmful to fish because of illegal fishing.

"We don't know how it's done, it's almost by definition not included in the quotas that are set for fish, often done in ways that are more destructive and undercut honest fisherman," said Laughren.

While one of the risks of fish fraud is that consumers pay more than they should for what they're getting, Laughren said there could also be health risks.

"Escolar is a fish that's often substituted for tuna in sushi restaurants. Escolar is nicknamed the laxative of the sea for reasons you can probably surmise on your own. Also, people have allergies," said Laughren.

'Very little checking'

There are two main drivers for fish fraud, according to Laughren.

The first, he said, is that often people can't tell by simply looking at the fish if it's the fish they ordered, as it might be battered or covered in sauce.

Secondly, seafood is a global commodity and there's "very little checking" at the border, he said.

"They follow long and complicated value chains so there's lots of opportunities throughout that value chain for the substitution to happen," Laughren said.