Tuna troubles – why your fish could be making you sick - Oceana Canada
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April 30, 2018

Tuna troubles – why your fish could be making you sick

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Oceana/Keith Ellenbogen


Tuna are one of the open ocean’s fastest and strongest predators, weighing up to 2000 pounds (900kg) and reaching lengths of nearly 13 feet (4m)! They are easily the largest species in the mackerel family, becoming prey to only the largest ocean predators such as toothed whales, sharks and, of course, humans.

Many species of tuna are the target of small and large-scale fisheries around the world. In fact, they are one of the most commercially valuable species on the planet. A single bluefin tuna once reeled in a price tag of over $700,000! Its value in the high-grade sushi market is enough to cause fisheries to target this species with almost unmatched effort, leaving many tuna populations decimated by overfishing.

And thanks to its high price tag and small population, species like bluefin tuna have become some of the most common fish to be caught up in seafood fraud.

Tuna in fishing net with diver

Photo Credit: Oceana/Keith Ellenbogen

The oppor-tuna-ty for fraud…

Seafood fraud is any dishonest activity that misrepresents the product being purchased.  Though seafood fraud takes many forms, of particular concern is species substitution. When you think you’re getting tuna, poor regulations around labelling means you may actually be getting something very different.

Oceana conducted a global review of more than 200 seafood fraud studies; 65 per cent of these studies found clear evidence of economically motivated mislabelling of products. This ‘bait and switch’ is when one type of fish, generally a cheaper or more readily abundant species, is sold as a more expensive fish.

When it comes to the word “tuna,” it is an umbrella term that encompasses 61 species scientists often categorize as “tuna” and “tuna-like fish.” In Canada, the only information required on seafood labels is a generic marketplace name and the country of origin. Naming protocols allow many different species to be listed under the same common name. For example, on the Canadian Food Inspection Agency’s Fish List, there are eight species of true tuna and six other species – that aren’t tuna – that can be sold under the name “tuna.”

However, these species don’t have much in common.  Some, like bluefin tuna, are critically endangered, while others are not. Levels of mercury also differ according not only to the species, but where it was caught. Unfortunately, in Canada consumers aren’t given the information they need to know which species they are purchasing or where it was harvested.

Tuna in a seafood market

Photo Credit: Oceana/Thierry Lannoy and Oceana/Pilar Marin

Are you really eating tuna?

Last summer, Oceana Canada conducted DNA testing in our nation’s capital, Ottawa, and found that almost 50 per cent of fish were mislabelled. Specifically, four of five samples of white tuna were actually escolar, a fish known as the “laxative of the sea.” This oily fish is not a species of tuna at all and can cause acute gastrointestinal symptoms such as diarrhea, vomiting and nausea. The health concerns are so severe that it is banned in Italy, South Korea and Japan.

We wish this was only a problem in Canada, but our colleagues from Oceana offices around the world have found similar examples of fraud. In Brussels, 95 per cent of bluefin tuna samples were fraudulent. And in the US, a shocking 94 per cent of white tuna samples were mislabelled, with 84 per cent of samples actually being escolar.

This ‘bait and switch’ phenomenon impacts public health and safety, cheats consumers, hurts honest, law-abiding fishers and seafood businesses as well as undermines the environmental and economic sustainability of fisheries and fish populations. It can even mask global human rights abuses by creating a market for illegally caught fish.

Kid investigating sushi with magnifying glass

Photo Credit: Miki Tiger

On World Tuna Day, we need your help to stop seafood fraud.

We are calling on the government and the CFIA to make combatting seafood fraud a priority by tracing seafood from boat to plate. Add your name to the petition today!