FACT SHEET - BENEFITS AND RISKS OF CONSUMING FISH AND SHELLFISH

Importance of Canada’s aquaculture industry

Aquaculture – the farming of fish, shellfish and aquatic plants in marine or freshwater – is one of the fastest growing food production industries in the world.

Fish farming in Canada has grown considerably over the past 10 years to keep pace with consumer demand for fresh, high quality fish. The demand for fish and seafood in North America alone is expected to increase up to 40 per cent by 2010.

The federal government recognizes the significant benefits associated with aquaculture and places a high priority on sustainable aquaculture development, food safety and consumer protection.

Benefits of eating fish and shellfish

There are many benefits to eating fish on a regular basis, whether they are wild or farmed. Studies show that people who eat fish at least once per week significantly lower their risk of heart disease and stroke. Furthermore, there is evidence that fish is beneficial for developing the fetal and infant brain.

Health benefits particularly around cardiovascular disease have been associated with fish consumption and to some extent attributed to omega-3 fatty acids. All fish, but particularly "fatty or oily fish" such as salmon, mackerel, herring, trout and sardines, contain significant amounts of omega-3 fatty acids. While fish is high in omega-3 fatty acids, these fatty acids alone cannot be said to account for all of the reported benefits. In addition, various preparation methods may negate any benefits; for example, fried or sandwich fish do not confer cardiovascular benefits

Fish is an excellent source of protein, calcium and minerals such as phosphorus, iron, selenium, potassium and vitamins including thiamine, riboflavin, and niacin, which are all important for achieving and maintaining good health

Shellfish can also contribute to a healthy, balanced diet. Shellfish species like mussels, clams, scallops, shrimp, oysters, lobster and abalone are low in calories and saturated fats, are also excellent sources of protein and contain omega-3 fatty acids. Like fish, shellfish contribute to health by providing essential minerals and vitamins such as iron, zinc and copper and vitamin B 12.

Farmed fish and shellfish - Consumer safety

Health Canada and the Canadian Food Inspection Agency (CFIA) work together to provide those living in Canada with one of the safest food supply systems in the world. This includes fish and seafood, both farmed and wild, available for retail sale.

Fish and shellfish, wild or farmed, can contain environmental contaminants, usually at very low levels. The CFIA regularly and routinely tests both imported and domestic fish and other food products for contaminants to ensure they are within acceptable levels set by Health Canada. Health Canada conducts annual Total Diet Surveys and conducts periodic fish and seafood surveys to better understand issues surrounding the consumption of various food products.

Health Canada studies indicate that trace amounts of mercury are routinely found in all types of fish and seafood. Mercury is a naturally occurring element found in lakes, streams and oceans. It can be released into the environment by human activities such as pulp and paper processing, mining operations, and burning fossil fuels. Mercury tends to accumulate in the food chain, so large, predatory fish species are at risk of higher levels; these include fresh/frozen tuna, swordfish and shark. Health Canada publishes consumer advisories for safe fish consumption for the general population and high risk groups (pregnant women and young children). Health Canada has established a guideline level for mercury in fish. This guideline is enforced by the CFIA.

Canadians should be aware of potential food-borne illnesses associated with the consumption of tainted, decomposed or unwholesome fish and fish products, including bivalve molluscs, shellfish with two hinged shells such as oysters, clams, scallops, and mussels. These include illnesses caused by shellfish carrying bacteria contaminated with marine biotoxins. Marine biotoxins are a group of naturally occurring toxins that sometimes accumulate in fish and shellfish. Many biotoxins are produced by microscopic marine algae (phytoplankton) and can accumulate in bivalve shellfish if they ingest these algae. There are several types of illnesses, such as Paralytic Shellfish Poisoning (PSP), connected with the consumption of contaminated bivalve shellfish.

Wild shellfish are harvested recreationally and commercially across Canada. Many of these species are also raised on farms through aquaculture operations on the Pacific and Atlantic coasts. All fish and shellfish harvested commercially, or from aquaculture operations, must meet Canadian food safety standards established by Health Canada.

The CFIA, DFO and Environment Canada work together on the Canadian Shellfish Sanitation Program – a monitoring program – to provide Canadians with early warning of PSP toxins (and other toxins) in bivalve shellfish, especially those individuals who wish to harvest their own shellfish.* To learn more about the CSSP and how to prevent shellfish poisoning due to PSP, please read CFIA’s factsheet entitled, "What I Need to Know Before Harvesting Shellfish This Summer".

For further information on aquaculture and food safety, visit these websites:

Fisheries and Oceans Canada – www.dfo-mpo.gc.ca

Health Canada – www.healthcanada.gc.ca/foodsafety

Canadian Food Inspection Agency – www.cfia-acia.agr.ca

*Note: Consumers who wish to harvest their own shellfish recreationally should confirm that the area is not under a harvest prohibition. This information can be obtained from the closest DFO office (consult the blue pages of your local telephone book). Also, look for signs posted around the affected area.

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Last Updated : 2006-06-28

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