An investigation has found that fish in Canada are often wrongly labelled The study said up to 44 per cent of samples from grocery stores and restaurants are wrongly labelled According to the study, snapper, yellowtail and butterfish were mislabelled 100 per cent of the time More than 30 per cent of cod, halibut, tuna and sole samples were mislabelled Oceana Canada says mislabelling means shoppers pay higher prices for a lower value fish and that shoppers may unknowingly eat other fish, like escolar, which can cause stomach problems The advocacy group says mislabelling can mask illegally caught fish