Eating Ontario Fish (2017-18)
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Key to using the guide
The numbers in the Key to using the guide are explained below.
1. The advisory tables accessible through the interactive map are divided into the Great Lakes and Inland Lakes.
2. Water body name.
3. The latitude and longitude, in degrees, minutes, seconds format; for example, 63°35'12"N 79°45'10"W.
4. The township, county, territorial district or geographical description of the water body.
Type of fish
5. Name of fish species tested. The table does not contain all species present at that particular location, only those that have been tested for contaminants.
Length of fish
6, 7. The total length of the fish is measured, from the tip of the nose to the tip of the tail. The fish length is expressed in both centimeters (cm) and inches (") at the top and bottom of the tables.
Number of meals
8. Recommended number of meals per month.
Each number is your total monthly intake and is not additive; see “Amount of Ontario fish you can eat in six steps” to understand how to track your monthly total.
9. Advice for general population.
10. Advice for women of child-bearing age and children under 15 (sensitive population).
11, 12. No advice provided for these lengths because fish of these sizes were not captured for contaminant monitoring.
For advisories not listed in the Guide, call
13. The number identifies the contaminant or group of contaminants which are causing consumption restrictions within a given species/location.
About the guide
Fish can be an important part of a balanced diet. They are a great source of high-quality protein, beneficial omega-3 fats, and other nutrients. At the same time, there is a risk of exposing ourselves and our families to harmful contaminants in fish, such as mercury. Based on their size, type, and location, certain fish may be more suitable to eat than others.
The Guide to Eating Ontario Fish provides easy-to-use information to help choose fish caught from Ontario lakes and rivers to minimize exposure to toxins. Consumption advice in the guide is based on guidelines provided by Health Canada.
This 29th edition contains more than 2,400 fishing locations, including over 80 new locations around the province. It is also available online at: Guide to eating Ontario Fish.
For certain locations, consumption advice may be given for specific species and/or size ranges which are not legal to possess under Ontario’s fishing regulations. Before going fishing, ensure it is legal to fish in the area, you have the required licence, and you are aware of any size or catch limits. To learn more about the rules on fishing in Ontario, visit the Fishing website.
Cautionary advice on eating fish
Consumption advice in this guide is provided for both the general population and the sensitive population.
This group includes women of child-bearing age (women who intend to become pregnant or are pregnant) and children younger than 15 years of age.
Women of child-bearing age, including pregnant women and nursing mothers, can affect the health of their baby through a diet elevated in contaminants such as mercury and polychlorinated biphenyls. Young children and developing fetuses are affected by contaminants at lower levels than the general population.
The sensitive population is advised to eat only the least contaminated fish (in the 32 to four meals per month categories), as reflected in the consumption advisory tables.
Individuals should further reduce their consumption of fish caught from Ontario waters if they regularly (four times per month or more) consume store-bought or commercial fish, including canned fish. They should not consume Ontario fish if they are consumers of Shark, Swordfish, or fresh or frozen Tuna. Health Canada suggests these fish should be consumed only occasionally.
General and sensitive populations
Consumption advice in this guide is based on an average meal of 227 grams of a skinless, boneless dorsal fillet (e.g., a fillet of dinner plate length) for an average size adult weighing 154 pounds. If you are an average size adult and your meal is substantially more than 227 grams, you should consume fewer than the recommended number of meals.
If eating fish parts, follow this cautionary advice:
- Do not eat organs of any fish. Fish organs can be high in both heavy metals and pesticides.
- Do not eat the eggs of fatty fish such as Salmon and Trout from the Great Lakes, as they generally contain higher levels of contaminants.
- Do not harvest dead or dying fish as they may contain harmful microorganisms or toxins.
Always follow proper food handling and storage techniques, as you would with any fresh meat product, to prevent the growth of harmful bacteria.
Sample advisory table
Find the advisory table on the interactive map for the location where the fish was caught. Tables are divided into Inland Lakes and Great Lakes.
Identify the type of fish caught. Refer to the Fish Identification section for more information.
Measure the total length of the fish (tip of nose to tip of tail) and refer to the appropriate length range on the table.
Use the location’s advisory table to learn how many meals of that fish can be eaten in a month.
The upper row (no shading) is for the general population and the lower row (grey shading) is for women of child-bearing age and children under 15 (sensitive population). The number represents the maximum number of meals of that size fish from that location that can be consumed each month, provided fish are not consumed from any other location or category.
Find the number of fillets equivalent to meals advised.
Consumption advice is based on an average meal of 227 grams or eight ounces (a fillet of dinner plate length) for an average-size adult weighing 70 kilograms (154 pounds).
See the fish conversion table to convert one meal of 227 grams (eight ounces) into roughly the same number of fish fillets (note: one fish contains two fillets).
Keep track of your total monthly intake.
Fish consumption advice is based on a combination of fish size, species and location. You may eat fish from different categories and locations as long as you track your consumption.
|Category (Fish meals per month)||Fraction of monthly intake total||Percentage of monthly intake total|
If you eat:
- Two meals in the 12-meal-per-month category, each meal will represent one-twelfth or 8.3% of your maximum monthly advised consumption for a total of one-sixth or 16.6% of your maximum monthly advised consumption (2 meals × 1⁄12 = 1⁄6 or 16.6%).
- One meal in the two-meal-per-month category, that meal will represent one-half or 50% of your monthly advised consumption (1 meal × 0.5 = 0.5 or 50%).
The total from these two groups equals 66.6% of your 100% total monthly advised consumption, and more fish up to a total of 100% can be consumed.
Fish conversion table
The following table can be used to convert one fish meal (227 grams or 8 ounces of fish) into an approximate equivalent number of fish fillets.
For example, the table below indicates that one meal (227 grams) of 30 cm Brook Trout is equivalent to approximately three fillets. Thus, if the consumption advisory for a 30 cm Brook Trout is 2 meals per month, a person could safely eat 6 fillets in one month (2 meals per month × 3 fillets per meal = 6 fillets per month).
|Fish length (cm)||15||20||25||30||35||40||45||50||55||60||65||70||75|
|Fish length (inches)||6”||8”||10”||12”||14”||16”||18”||20”||22”||24”||26”||28”||30”|
Consumption of fish outside the advisory table range
The advisory tables do not contain all types of fish at that location, only those that have been tested for contaminants. Advisories are provided only for the size ranges of fish that were tested. Since it is well known that contaminant levels generally increase with fish length, the following rules can be applied:
- For fish smaller than the advisory table range, follow the advice for the smallest tested range.
- For fish larger than the advisory table range, consumption advice cannot be predicted, except that it is likely to be more restrictive than the largest tested range. This means fewer of these fish should be consumed.
Prohibited and Restricted species
American Eel - Recreational fishing for American Eel is prohibited as the species is listed as endangered under the Endangered Species Act. If you catch an American Eel, you must release it, but you can help determine where they currently are in Ontario. If you see or catch an eel, you can report it online through Natural Heritage Information Centre’s iNaturalist project or by email to email@example.com.
Lake Sturgeon – Recreational fishing for Lake Sturgeon is prohibited in areas where populations are listed as threatened under the Endangered Species Act. Catch and release of Lake Sturgeon is still permitted in areas where populations are not identified as threatened. If you catch a Lake Sturgeon, you must release it, but you can help determine where they currently are in Ontario. If you see or catch a sturgeon, you can report it online through Natural Heritage Information Centre’s iNaturalist project or by email to firstname.lastname@example.org.
Muskellunge – To maintain healthy Muskellunge populations, the Ministry of Natural Resources and Forestry encourages catch and release of this species as it cannot handle the pressures of heavy fishing. They will also likely have elevated levels of mercury and should not be consumed by anyone.
Reducing the risk from contaminants in fish
Here are three quick tips for eating less contaminated fish:
- Eat smaller fish. Smaller fish tend to be much less contaminated than larger fish of the same species.
- Eat leaner fish from the Great Lakes. In the Great Lakes, species such as Bass, Pike, Walleye, Perch and panfish tend to have much lower contaminants than fatty species like Salmon and Trout.
- Eat panfish or whitefish from inland locations. At inland locations, top-predatory fish such as Pike and Walleye generally have greater contaminants than panfish or whitefish.
Preserving and preparing fish for cooking
A number of anglers fish for the thrill of the catch, and release their fish to allow them to be caught again. If you decide to keep and eat your catch, chill freshly caught fish on ice or in a refrigerator as soon as possible to avoid spoilage. Clean, dress and refrigerate or preserve the fish at the earliest opportunity.
Clean and cook fish to reduce contaminants
Toxins such as polychlorinated biphenyls, pesticides and dioxins concentrate to the highest levels in fish with fatty flesh such as Salmon, Trout, Carp and Catfish.
Before cooking, remove the skin, trim off the fatty areas and discard the flesh around the belly area. You can further reduce contaminants by allowing fat to drip away during cooking (e.g., grilling, broiling or baking). If you deep fry fish, do not re-use the oil.
NOTE: Toxins such as mercury and perfluorooctane sulfonic acid, are evenly distributed in fish flesh so there is nothing you can do to reduce or remove them.
How to trim and cook fish to reduce contaminants:
1. Remove fillet.
2. Remove skin and fat along the side and belly.
3. Cook on a rack or grill to let fat drip away.
Contaminants in fish
Ontario is not unique in having consumption restrictions on fish. Most jurisdictions in North America also have them. An extensive review of consumption restrictions on fish in North America is available in the US EPA website.
The contaminants found in fish can come from local sources and from sources thousands of kilometers away. Airborne contaminants can travel long distances in the atmosphere, and return to the earth in rain and snowfall. Mercury, polychlorinated biphenyls and toxaphene are a few of the contaminants that are known to be transported long distances and can cause low-level contamination even in isolated lakes and rivers.
Superscripts in the advisory tables identify the contaminant or group of contaminants that are causing consumption restrictions within a given species/location:
- Mercury - Mercury, is converted to methylmercury and absorbed by a fish either from water passing over its gills or it is ingested with its diet. Since fish eliminate mercury at a very slow rate, concentrations of this substance gradually increase. Fish at the top of the food web such as Walleye and Pike usually have the highest mercury levels.
- Polychlorinated biphenyls (PCBs) - PCBs are a group of chlorinated organic compounds first commercially developed in the late 1920s and banned in the 1970s. They persist for decades in the natural environment and readily accumulate in the aquatic ecosystem.
- Dioxin-like PCBs - These are a select group of PCBs with harmful properties similar to dioxins.
- Dioxins/Furans - Dioxins and furans are unintentional by-products of several industrial processes and, in some cases, incomplete combustion. Of 210 different dioxins and furans, 17 are toxic enough to be of concern.
- Toxaphene - Toxaphene is an extremely persistent insecticide in the aquatic environment. It was removed from general use in Canada in 1974 and restricted in the United States in 1982.
- PerFluoroAlkyl and PolyFluoroAlkyl Substances (PFAS) - PFAS are a family of chemicals that make materials water, stain and oil repellent and have been in a wide array of consumer products since the 1950s. PFAS do not break down easily.
- Selenium - Selenium is a metal found in fish tissue but only occasionally at levels requiring consumption restrictions.
- Arsenic - Arsenic is a metal found in fish tissue but only occasionally at levels requiring consumption restrictions.
- PolyBrominated Diphenyl Ethers (PBDEs) - PBDEs are used as flame retardants in building materials, electronics and many household products. Some of these chemicals have been banned or phased out in recent years.
- PolyChlorinated Naphthalenes (PCNs) - PCNs are industrial chemicals. While no longer used in Canada, they may be produced unintentionally in different chemical processes.
- Chromium - Chromium is a metal found in fish tissue but only occasionally at levels requiring consumption restrictions.
- Photomirex - See mirex below.
- Mirex - Mirex is a chlorinated carbon compound used as a pesticide in the southern United States but never registered for such use in Canada. Some mirex is transformed into photomirex.
- Lead - Metals such as lead are found in fish tissue but only occasionally at levels requiring consumption restrictions.
- Cadmium - Cadmium is a metal found in fish tissue but only occasionally at levels requiring consumption restrictions.
For more information on these substances, please contact the Fish Contaminant Monitoring Program at
Advice on eating freshwater food
Eggs can have elevated levels of organic contaminants because of their higher fat content. It is recommended that you avoid eating eggs from fatty fish species, from the Great Lakes.
Freshwater clams and snapping turtles
Clams are filter feeders and are usually low in contaminants, but you should avoid eating them as they can contain harmful bacteria and other pathogens. Snapping turtles may have high levels of contaminants in their fat, liver, eggs and, to a lesser extent, muscle. If eating snapping turtle, trim away fat prior to cooking the meat or preparing soup. Also, avoid eating the liver and eggs of the turtle. Women of child-bearing age and children under 15 should avoid eating any part of snapping turtles, including soups made with their meat.
Fish with black spots, tumours and/or worms
Fish can sometimes have worms, grubs and cysts in their flesh, around the intestines, or on the skin, fins or gills. These parasites are a normal part of the ecosystem and the edible portions containing parasites do not present a health hazard if properly cooked.
Occasionally, you may catch a fish with external growths, tumours, sores or other lesions. These generally result from viral or bacterial infections. In general, there are no significant differences in contaminant levels of fish with or without tumors from the same water body. While the appearance of viral or bacterial infections in fish is unsightly, there is no known health risk from consuming an infected fish that meets the consumption advisories as long as they are prepared properly.
As a general precaution, avoid eating fish that appear to be sick, dying or dead when caught. For more information on some of these diseases, visit Fish and wildlife health.
Some blue-green algae species can produce toxins called microcystins. These toxins can accumulate in fish. Preliminary research suggests that when possible, you should avoid eating fish and fish organs from areas where major blue-green algal blooms occur during and at least two weeks after the bloom.
Updates to the guide
The guide is published every two years and any major changes in consumption advice that arise between guide publications are made public at Guide to eating Ontario fish.
For questions about the guide, please contact:
To report pollution or a large number of dead fish, call the Spills Action Centre at
Fish consumption advisory tables for inland and Great Lakes locations
The location-specific advisory tables for the waterbodies tested can be accessed through the interactive map.
It is not possible to test fish from all the lakes, rivers and streams in Ontario. Locations in the guide meet one or more of the following criteria: known or popular fishing area; known or suspected source of pollution nearby; major food source for local residents; being developed for recreational or industrial purposes; and part of a monitoring program for long-term studies of contaminants in fish.
The selection of testing sites is an ongoing process and public input is welcome. Contact email@example.com for more information.
Learn how to identify fish
To make sure your catch is safe to eat, you must be able to identify it. The following information describes the fish you are most likely to catch in Ontario.
Information about fish traits are from the Freshwater Fishes of Canada by Scott and Crossman.
The following illustrations were provided by Curtis Atwater: American eel, black crappie, bluegill, bowfin, brook trout, brown bullhead, brown trout, channel catfish, chinook salmon, common carp, freshwater drum, goldeye, lake herring (cisco), lake sturgeon, lake trout, largemouth bass, mooneye, rainbow trout, redhorse sucker, round whitefish, sauger, smallmouth bass, walleye, white bass, white crappie, and white perch, and yellow perch.
- Atlantic Salmon
- American eel
- Black Crappie
- Brook Trout
- Brown Bullhead
- Brown Trout
- Channel Catfish
- Coho Salmon
- Chinook Salmon
- Freshwater Drum
- Cisco (or Lake Herring)
- Lake Sturgeon
- Lake Trout
- Lake Whitefish
- Largemouth Bass
- Northern Pike
- Pink Salmon
- Rainbow Smelt
- Rainbow Trout
- Redhorse sucker
- Rock Bass
- Round Whitefish
- Smallmouth Bass
- White Bass
- White Crappie
- White perch
- White sucker
- Yellow Perch
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