Fish mercury: how many grams a week reach the limit
As audited on 2026-10-17, counted eaten alone, from zero: Reaching the mercury limit takes about 7 kg of canned sardines in a week, or 91 g of swordfish (FDA's survey; swordfish isn't one of our reviewed foods). Most of the fish people actually eat sits far below the line.
Checked against its sources, in English and French, on 2026-10-17, with data v0.2. The text is as audited; any figure that comes from the live database is recomputed when the page loads and must still match it.
Audited with data v0.2 and method v0.2. The site is now on data v0.6, method v0.4.
Still holds: The studies, surveys and limits it cites, and every figure bound to the live data: those are recomputed when the page loads and must still match, or this page would not show.
What has moved: Since 18 October the food pages count grams to a limit from the room left after an average adult’s intake, so their gram figures are smaller than this card’s, which count from zero. The card is as audited; see the correction of 18 October.
The fish matters far more than how often you eat it.
| Fish (one serving) | Mercury per serving | Eaten alone, grams a week to reach the limit (≈ servings) | Same, Health Canada's limit for pregnancy and young children ◆ | Health Canada's advice |
|---|---|---|---|---|
| Canned sardines (55 g) | 0.7 µg | 7,000 g (≈ 127) | 7,540 g | no limit |
| Farmed salmon, baked (100 g) | 2.1 µg | 4,330 g (≈ 43) | 4,670 g | no limit ("very low") |
| Atlantic mackerel, raw (125 g) † | 5.6 µg | 2,020 g (≈ 16) | 2,180 g | no limit (on its "very low" list) |
| Canned light tuna (55 g) | 4.5 µg | 1,100 g (≈ 20) | 1,190 g | no limit ("does not apply to light tuna") |
| Canned albacore (white) tuna (55 g) | 19.7 µg | 253 g (≈ 4.6) | 273 g | limits for pregnancy, breastfeeding and children only |
Not yet reviewed by us (agency survey means only, not ranked):
| Fish (125 g raw) | Mercury per serving | Eaten alone, grams a week to reach the limit (≈ servings) | Same, Health Canada's limit for pregnancy and young children ◆ | Health Canada's advice |
|---|---|---|---|---|
| Fresh or frozen yellowfin tuna | 44 µg | 257 g (≈ 2) | 277 g | 150 g a week, all six fish combined ★ |
| Shark | 122 µg | 93 g (less than one) | 100 g | 150 g a week combined ★ |
| Swordfish | 124 µg | 91 g (less than one) | 98 g | 150 g a week combined ★ |
- The limit is EFSA's tolerable weekly intake for methylmercury, 1.3 µg per kg of body weight: 91 µg a week for a 70 kg adult. Every gram figure assumes 70 kg and scales with body weight: a 20 kg child reaches it on 3.5 times fewer grams.
- ◆ Health Canada's limit for women of child-bearing age, pregnant women and young children is 0.2 µg per kg a day: 98 µg a week at 70 kg, close to EFSA's. Its general adult value is more lenient (0.47 µg per kg a day, about 230 µg a week), which is why its swordfish line (150 g a week) sits above ours.
- ★ Health Canada's six: fresh or frozen tuna, shark, swordfish, marlin, orange roughy and escolar, 150 g a week combined for the general population; 150 g a month for women who are or may become pregnant or are breastfeeding.
- Pregnancy, breastfeeding and children: follow Health Canada's own advice, not this card. The FDA/EPA list sardines, salmon, Atlantic mackerel and canned light tuna as "Best Choices" for those groups.
- Beside the grams, not subtracted: EFSA finds average adults stay under the limit from their whole diet; high fish eaters may go over it.
- Mercury is counted as if all of it were methylmercury (Health Canada: most mercury in fish is), so each figure is an upper bound.
- † Reviewed after dataset v0.2 was published.
- Data: CFIA surveys of canned tuna (2000–2021) and Atlantic mackerel (2004–2020); FDA surveys of sardines, shark, swordfish and yellowfin (1990–2012); FDA Total Diet Study for salmon (2018–2020). Grade A for the five reviewed fish.
Foodtopsy · audit dated 2026-10-17, on dataset v0.2 and method v0.2 · sources and corrections: the receipt below · corrections · Information, not medical advice.
Where each number comes from
Where every figure on the card comes from.
Limit: EFSA CONTAM Panel 2012, EFSA Journal 10(12):2985, doi:10.2903/j.efsa.2012.2985: "the Panel established a TWI for methylmercury of 1.3 µg/kg b.w., expressed as mercury" (abstract, read at the EFSA Journal page 2026-10-17). × 70 kg (EFSA's adult default) = 91 µg a week. Same abstract: "The mean dietary exposure across age groups does not exceed the TWI for methylmercury, with the exception of toddlers and other children in some surveys… High fish consumers, which might include pregnant women, may exceed the TWI by up to approximately six-fold."
Servings: Health Canada, Table of Reference Amounts for Food: I.4 canned fish 55 g; I.3 fish 125 g raw / 100 g cooked.
Arithmetic: grams a week to the limit = 1.3 µg/kg × 70 kg ÷ concentration in µg/g = 91 ÷ µg/g (the headline figure); Health Canada's pregnancy and young-children figure = 0.2 µg/kg/day × 7 × 70 kg = 98 ÷ µg/g; ≈ servings = grams ÷ serving (= 91 µg ÷ per serving); per serving = concentration × serving (all derived from concentrations).
Canned sardines, with bones (55 g)
- Concentration (mean) · n · years · source
- 0.013 ppm · 90 · FDA 2002–2010 · FDA, Mercury Levels in Commercial Fish and Shellfish (1990–2012) (median 0.010, max 0.083; canned vs fresh not stated)
- Grams a week to 91 µg
- 7,000 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 7,540 g
- Per serving
- 0.715 µg
- Servings a week to 91 µg
- 127
- One serving as a share of the limit
- 0.8%
- Also in the receipt
- Dataset row grade A. CFIA canned sardines 2020: 0.01 ppm (one sample), context only
Farmed Atlantic salmon, baked (100 g)
- Concentration (mean) · n · years · source
- 21 µg/kg total mercury · 27 (27 detected) · FDA Total Diet Study, fiscal years 2018–2020, food 318
- Grams a week to 91 µg
- 4,330 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 4,670 g
- Per serving
- 2.1 µg
- Servings a week to 91 µg
- 43
- One serving as a share of the limit
- 2.3%
- Also in the receipt
- CFIA raw Atlantic salmon 2002–2021 (n 209, 37% non-detect): 12.8–27.9 µg/kg, 1.6–3.5 µg per 125 g raw, 26–57 servings. FDA fresh/frozen salmon 0.022 ppm (n 94). Farmed vs wild not recorded in either
Atlantic mackerel, raw (125 g) †
- Concentration (mean) · n · years · source
- 45.0 µg/kg total mercury · 11 samples · 2004–2020 · CFIA fish metals, MACKEREL, ATLANTIC edible portion
- Grams a week to 91 µg
- 2,022 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 2,178 g
- Per serving
- 5.62 µg
- Servings a week to 91 µg
- 16
- One serving as a share of the limit
- 6.2%
- Also in the receipt
- Canned Atlantic mackerel: 2 imported samples only (18 µg/kg), not used. The mackerel rows end with a king-mackerel line (CFIA 0.268 ppm, 7 of 54 over 0.5 ppm), a different species
Canned light tuna (55 g)
- Concentration (mean) · n · years · source
- 82.5 µg/kg (middle bound; 78–86.9) · 219 cans (skipjack 195, yellowfin 24) · CFIA 2000–2020
- Grams a week to 91 µg
- 1,103 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 1,188 g
- Per serving
- 4.54 µg
- Servings a week to 91 µg
- 20
- One serving as a share of the limit
- 5.0%
- Also in the receipt
- FDA canned light 0.126 ppm (n 545): 6.9 µg, 13 servings. Sampling is surveillance and import testing, not random retail
Canned albacore (55 g)
- Concentration (mean) · n · years · source
- 359 µg/kg (middle bound) · 265 cans · CFIA 2000–2021
- Grams a week to 91 µg
- 253 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 273 g
- Per serving
- 19.7 µg
- Servings a week to 91 µg
- 4.6
- One serving as a share of the limit
- 22%
- Also in the receipt
- FDA canned albacore 0.350 ppm (n 451): 19.3 µg, 4.7 servings. The dataset's rating for this row is a draft; the card uses only the arithmetic
Fresh/frozen yellowfin (125 g raw)
- Concentration (mean) · n · years · source
- 0.354 ppm · 231 · FDA 1993–2010
- Grams a week to 91 µg
- 257 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 277 g
- Per serving
- 44.3 µg
- Servings a week to 91 µg
- 2.1
- One serving as a share of the limit
- 49%
- Also in the receipt
- Imported food row (USDA SR Legacy 15127), not reviewed
Shark (125 g raw)
- Concentration (mean) · n · years · source
- 0.979 ppm · 356 · FDA 1991–2007
- Grams a week to 91 µg
- 93 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 100 g
- Per serving
- 122.4 µg
- Servings a week to 91 µg
- 0.74
- One serving as a share of the limit
- 134%
- Also in the receipt
- Imported (USDA SR Legacy 15095)
Swordfish (125 g raw)
- Concentration (mean) · n · years · source
- 0.995 ppm · 636 · FDA 1990–2010
- Grams a week to 91 µg
- 91 g
- Grams a week to 98 µg (Health Canada, pregnancy and young children)
- 98 g
- Per serving
- 124.4 µg
- Servings a week to 91 µg
- 0.73
- One serving as a share of the limit
- 137%
- Also in the receipt
- Imported (USDA SR Legacy 15110)
Health Canada (Mercury in Fish, modified 2024-07-25, and Mercury in Fish: Questions and Answers, modified 2019-11-27; both read in full 2026-10-17):
- "In general, you can eat up to 150 g per week of these fish species combined. However, women who are or may become pregnant and breastfeeding mothers can eat up to 150 g per month. Young children between 5 and 11 years of age can eat up to 125 g per month. Very young children between 1 and 4 years of age should eat no more than 75 g per month" (fresh/frozen tuna, shark, swordfish, escolar, marlin, orange roughy).
- Canned albacore: 300 g a week for women who are or may become pregnant and breastfeeding mothers, 150 g for children 5–11, 75 g for children 1–4. The 2024 page: "The advice does not apply to canned light tuna, nor does it apply to Canadians outside of the specified groups." The 2019 Q&A says a general-population adult "could eat up to six 170-g cans of canned albacore tuna (as long as they were not eating any of the predatory fish listed…)", with no time unit in the sentence. The card follows the newer page.
- "There are no recommended consumption limits for any other types of retail fish in Canada besides" the six and canned albacore. Salmon: "The levels of mercury in the muscle tissue of salmon are very low." Sardines are named on neither page.
- Health Canada's own values: 0.47 µg/kg bw/day for adults of the general population (JECFA's), 0.2 for women of childbearing age, pregnant women and young children. Note the tension: its canned-albacore allowance for pregnancy (300 g a week) at CFIA's 359 µg/kg is 108 µg a week, above its own 0.2 value at 70 kg (98 µg; 273 g of albacore). Health Canada's derivation of the 300 g wasn't opened. "Most of the mercury present in fish tissue is in the form of methylmercury."
FDA/EPA, Advice about Eating Fish (revised October 2021, current as of 2024-03-05; aimed at people who are or might become pregnant or are breastfeeding, and children 1–11): salmon, sardines and "Tuna, canned light (includes skipjack)" are Best Choices; albacore and yellowfin are Good Choices; king mackerel, marlin, orange roughy, shark, swordfish, Gulf of Mexico tilefish and bigeye tuna are Choices to Avoid.
Also from the FDA table, not on the face (no food row in the dataset): bigeye tuna 0.689 ppm (n 21): 86 µg per 125 g, about 1 serving; king mackerel 0.73 (n 213): 91 µg, 1.0; orange roughy 0.571 (n 81): 71 µg, 1.3; marlin 0.485 (n 16): 61 µg, 1.5; fresh/frozen albacore 0.358 (n 43): 45 µg, 2.0. No bluefin row exists in the FDA table, though the dataset holds bluefin food rows.
Total or methyl: the FDA table never says which; its column reads "mercury concentration". CFIA and the FDA Total Diet Study report total mercury. Every figure is treated as methylmercury, an upper bound.