Mercury from natural or industrial sources is the main environmental contaminant of fish in Québec. It is found in fish in the form of methylmercury.
In Québec, the marketing of fish is subject to quality control measures. Therefore, most species are safe to eat. Some types of fish must, however, be eaten in moderation, particularly game fish such as:
The flesh of these types of fish may contain higher levels of methylmercury or other environmental contaminants. This is because these predatory fish are high in the food chain, that is, they eat other fish, causing toxic substances to accumulate in their flesh. However, younger or smaller fish contain lower levels of contaminants.
Consumption of these types of fish should be limited to the recommended number of servings in order to reduce the health risks associated with methylmercury. The fish consumption advisories issued by Health Canada concern pregnant women in particular, since the fetus’s developing nervous system is more sensitive to methylmercury.
Overall, the risk of methylmercury poisoning from eating fish is very low in Québec.
For more details about the health risks associated with methylmercury, consult the Mercury and Human Health page on Government of Canada’s website.
Pollution of the aquatic environment
Clean-up efforts in recent decades have improved the quality of Québec’s aquatic environment, particularly that of the St. Lawrence River. Therefore, the flesh of fish that live in the St. Lawrence now contains much lower levels of mercury and other toxic substances such as polychlorinated biphenyls (PCBs). You will find more details about contaminant concentrations in freshwater fish in the document Toxic Contamination of Freshwater Fish produced by the Ministère de l'Environnement et de la Lutte contre les changements climatiques.
Fish parasites and abnormalities
Sometimes, fish can contain parasites. Most of these parasites are harmless and are destroyed by cooking. Physical abnormalities that are sometimes seen in fish do not necessarily mean that their natural environment is contaminated.