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Mercury and Retail Fish

Printable Fact Sheet (PDF)

Everyone, including pregnant women (see Fish Consumption) should eat fish and shellfish. Canada’s Food Guide recommends eating at least 2 servings of fish each week (total of 150 grams or 5 ounces) because of the excellent nutritional value.

However, there is a concern about mercury in seafood. Most seafood contains only a tiny amount of this substance. Men and women who are not in their childbearing years should enjoy a variety of fish, but should limit high mercury fish to 1 serving per week.

We can all safely enjoy fish and shellfish in our diets by being aware of the types of seafood to limit or avoid!

Why is it important to eat fish and shellfish?

Fish and shellfish are an important part of your diet because they are:

  • A source of protein and other essential nutrients
  • Low in saturated fat
  • A source of omega-3 fatty acids.

What are omega-3 fatty acids?

Omega-3 fatty acids are a special kind of healthy fat needed for human health. It’s important in our diet because our bodies do not produce them. Everyone benefits from them, including children. Omega-3 fatty acids have a protective effect against heart disease and are essential for the development of vision, the brain, and nerves of an unborn child.

What is mercury?

Mercury is a poisonous heavy metal that can be found naturally in soil, rocks, and also in lakes, streams and oceans. Besides natural sources, mercury is also released into the environment by human activities such as pulp and paper processing, mining operations, and burning garbage and fossil fuels.

In lakes and rivers, mercury can bind tightly to the proteins in fish tissue. Most fish have trace amounts; however, mercury tends to build up in the food chain. For this reason, higher-mercury fish are usually big, predatory fish that have eaten other lower-mercury fish over the course of their long lives.

Health Canada has established a guideline level for mercury content in most retail fish. This regulation is enforced by the Canadian Food Inspection Agency (CFIA).

Can pregnant women and children eat fish and shellfish?

There are a few types of fish and shellfish that contain higher amounts of mercury that could harm an unborn baby or a young child’s developing nervous system. Women who could become pregnant, women who are pregnant, nursing mothers, and young children should avoid higher-mercury fish, and instead eat fish that is low in mercury to get all the benefits of fish, including omega-3 fatty acids. Please see the Fish Consumption fact sheet titled Fish Consumption Advice for Small Children, Women of Childbearing Age, and Pregnant Women chart for specific fish consumption advice.

What about sport fish?

Sport fish are fish caught by family and friends in local lakes and rivers. Some local sport fish, especially the larger fish, are more highly contaminated. Women who could become pregnant, women who are pregnant, nursing mothers, and families with young children should consider the potential contamination of sport fish.

If you eat sport fish, you need a copy of the Guide to Eating Ontario Sport Fish. This can be obtained through the Ontario Ministry of the Environment and Climate Change website and will give you information about what fish you can eat and how often. The guide is published every other year, and is available free of charge from the provincial government offices.

Where can I find more information?

For more information and to speak to a public health professional, call Health Connection Monday to Friday at 705-721-7520 (1-877-721-7520) and review the following resources:

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