The fish you buy might not be the fish you thought it was.
A viral twitter thread from Jen McDonald, a biology professor at Fanshawe College, explained how samples of fish her class collected from both the grocery store and restaurants were mislabeled.
Her students sourced fish they thought was Icelandic cod, red tuna, white tuna and red snapper and sent the fish to the lab to be tested, but received varying results.
Both the red tuna and the red snapper were identified as tilapia — a white fish that could have been dyed red. The two samples of white tuna were identified as yellowfin tuna, and escolar, a type of fish banned in Japan for an oil it contains that has laxative properties (it is not banned in Canada).
The Icelandic cod was identified as Icelandic cod, one of only two correct identifications, according to McDonald. The cod was sourced from a grocery store and was certified by the Marine Stewardship Council.
Another finding that was worrisome: one of the samples was unrecognizable and contained body louse, McDonald said on Twitter.
The experiment mimicked other research in the topic, which has found up to 30 per cent of fish has been mislabeled in Canada.
It’s a problem, explained Tammara Soma, assistant professor and director of the Food Systems Lab at Simon Fraser University, because “an undeclared ingredient is always a big issue.”
“As the professor mentioned, one of the fishes actually can be dangerous for those with allergies,” Soma explained. “That becomes a huge problem, it can be deadly in some cases.”
So how can Canadians know they’re getting what they pay for?
Beyond actually going fishing ourselves, there are a couple of things we can do, food systems experts say.
One solution is to buy fish locally, cutting out the middlemen of the food supply chain in the process.
“Basically, the longer the distance and the longer the food supply chain is, the easier it is for resources to get over-exploited but also the easier it is for things like this to happen where people aren’t sure what they’re eating,” Soma told Global News.
“So to address that particular issue … going local specifically, as well as trying to find community supported fisheries or stores that sell these particular fish products, then … it’s easier to kind of like trace back things.
“Basically cutting out all of the steps that might make it more easy to adulterate the fish or to switch things around.”
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For those who still shop at the grocery store, there are options available, including buying the fish with the head still attached — which makes it more difficult to misidentify.
“Unless you buy the fish with the head attached to it, it’s difficult to really know which species you are dealing with,” Sylvain Charlebois, food systems professor at Dalhousie University, told Global News.
Consumers can also look at the label for certified products, as the Icelandic cod was in McDonald’s experiment.
The label provides an extra layer of verification, only being put on fish that was obtained sustainably. But ultimately it’s the responsibility of the grocer to make sure they’re selling you the correct fish.
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“Labelling is a shared responsibility, but the onus is on the retailer to make sure labelling is accurate,” Charlebois explained.
But the best thing a consumer can do is ask questions at your local grocery store, according to Taylor Witkin, Network Coordinator for LocalCatch.org, which promotes shortening the supply chain.