Fishing takes its place in many cultures in Northern Ontario. It can be a relaxing way to connect with nature and be active, with an added bonus of catching a tasty supper. Unfortunately, even though fish provide many important nutrients, it is helpful to limit certain types and sizes to lower exposure to mercury and other contaminants.
The recommendation to include fish at least twice per week is largely due to their omega-3 content, which helps protect our heart, memory and mental health. Many people could benefit from including more omega-3 oils in their weekly routine, and fish are the largest food source of this nutrient.
Sadly, fish are easily infected by pollutants when contaminated water passes through their gills, and when they eat smaller infected fish. The World Health Organization states that mercury causes problems with nerves, digestion, breathing, immunity and brain development during pregnancy. Mercury might be linked to developing cancer as well. Other problem contaminants in some local lakes include PCBs (industry chemicals increasing the risk of cancer), dioxins/furans (industry by-products increasing the risk of cancer, reproductive and developmental problems) and toxaphene (insecticide affecting many organs and the nervous system).
On the plus side, pollutants in fish are often at low enough levels to be safely consumed on a regular basis. The Ontario government tracks and reports toxin levels in fish around Ontario, however keep in mind that contamination may also be present in isolated areas with no tracking. Common local species can be found in the table below, but other species and lakes can be found here: https://www.ontario.ca/page/eating-ontario-fish-2017-18.
Recommended Maximum Meals* of Fish per Month:
Other tips to lower mercury intake:
- Eat leaner fish from the Great Lakes. Lean choices like bass are lower in contaminants than fatty fish like trout.
- Keep smaller, younger fish. Fish build up more and more mercury with time, so older larger fish will have higher mercury levels.
- Choose smelt, whitefish or lake herring from inland locations. Larger fish at the top of the food chain (such as walleye) usually build up more mercury from regularly eating contaminated smaller fish.
- Avoid fish organs and eggs as they usually have higher levels of contaminants.
Because of the omega-3 fats in fish, it is still recommended to eat them at least twice per week. Choosing ones lower in pollutants will allow you to enjoy them more often, so keep fishing for those health benefits!
Michelle Stevens, RD