DNA barcoding reveals widespread seafood fraud in Metro Vancouver

Researchers from UBC are developing new techniques to identify the seafood sold in Metro Vancouver and they say their findings, released Friday, point to widespread seafood fraud.

Wild or farmed salmon? Snapper or cod? How do you know you're actually getting the fish you pay for?

UBC researchers are using DNA barcoding to pinpoint the type of fish being sold and are finding, in many instances, you're always not getting the fish you think you are. (Elaine Thompson/Associated Press)

UBC researchers are developing new techniques to identify the seafood sold in Metro Vancouver and they say their findings, released Friday, point to widespread seafood fraud.

By using a technique called DNA barcoding, researchers were able to identify the genes of fish from a survey of 300 samples in Metro Vancouver from both sushi restaurants and grocery stores.

The barcoding method compared all the data with an extensive library of fish DNA constructed by researchers at the University of Guelph, who have been growing their database for a decade.

Dr. Xiaonan Lu, UBC associate professor of food science, said the most commonly mislabelled fish sold on the market is red snapper.

"The mislabelling rate is 100 per cent ... for example, they're actually tilapia or rockfish ... but they're labelled as red snapper," Lu told On The Coast guest host Laura Lynch. He found that mackerel and tuna were the least likely to be mislabelled.

With this identification method it can take up to a few days to get results back, so Lu's team has developed a prototype that will hopefully produce quicker results. The spectrometer they've created weighs about two kilograms and costs about $20,000 to make.

"We're still trying to reduce the size of the device so the consumer can carry it to the grocery store and do the testing by themselves," he said, predicting that one day the technology will be affordable and accessible to the public.

The reason seafood suppliers are able to mislabel fish so easily is because of the long process of importing fish.

"The whole seafood supply chain is very complicated and it's not very transparent, so when you harvest the fish there will be a lot of different steps for the processing and this fish product may cross several different national borders," Lu said.

Once the head and skin of the fish have been removed, it can be difficult for consumers and professionals to tell the difference based on the raw fillet.

When Lu goes shopping, he often tries to buy the whole fish, scales and all, because then it's harder for suppliers to mislabel the product.

He also recommends buying fish on a seasonal basis, especially when it comes to salmon.

"In summer, in Metro Vancouver, we should have a lot of wild salmon, but we only have a five or six month window that we have just farmed salmon."

To hear the full interview listen to media below:

Wild or farmed salmon? Snapper or cod? How do you know you're actually getting the fish you pay for? 6:54

With files from On The Coast