Is Mackerel Full of Mercury? Separating Species and Safety

January 1, 2026 •

3 min read

According to the U.S. FDA, mercury levels in mackerel vary dramatically by species, with larger predatory types containing significantly more than their smaller counterparts. Understanding this distinction is key to safely enjoying the health benefits this oily fish provides without concern over harmful mercury exposure.

Quick Summary

Mercury levels in mackerel differ significantly between species. While Atlantic mackerel is low in mercury and considered a 'Best Choice,' larger predatory varieties like king mackerel are high and should be limited or avoided.

Key Points

Species Matters: Not all mackerel are the same; mercury levels vary significantly between species.
Atlantic Mackerel is Safe: The smaller Atlantic mackerel has very low mercury levels and is a "Best Choice" according to the FDA and EPA.
King Mackerel is High in Mercury: The larger, predatory king mackerel contains high levels of mercury and should be avoided, especially by vulnerable populations.
Canned is Low-Mercury: Most canned mackerel uses low-mercury species like Atlantic mackerel and is considered safe for regular consumption.
Size and Diet are Key: A fish's size, lifespan, and diet determine its mercury content, with larger predators accumulating more over time.
Consult Guidelines: Always refer to the latest FDA and EPA guidelines for specific fish consumption recommendations, especially for at-risk groups like pregnant women.

The Mercury Spectrum in Mackerel Species

Mercury is a naturally occurring element that can accumulate in fish as methylmercury, a process called bioaccumulation. Larger, predatory fish higher up the food chain tend to have higher concentrations of mercury. The term "mackerel" encompasses numerous species, and their size and diet influence their mercury content.

Atlantic Mackerel: The "Best Choice"

Atlantic mackerel is widely considered one of the safest mackerel species to eat due to its low mercury levels. Being smaller and having a shorter lifespan and a diet of plankton and small crustaceans, they accumulate less mercury. The FDA and EPA recommend Atlantic mackerel as a "Best Choice" and suggest enjoying it two to three times per week.

King Mackerel: The High-Mercury Species

King mackerel, a large predatory fish, is at the high end of the mercury spectrum and is on the FDA's list to avoid, especially for vulnerable groups. Their size and diet of smaller fish contribute to significant mercury accumulation. Pregnant women, breastfeeding mothers, and young children are advised to avoid king mackerel due to potential neurological risks from mercury toxicity.

Spanish Mackerel: A Moderate-to-High Concern

Spanish mackerel has moderate mercury levels, but these can vary regionally. Those caught in the Gulf of Mexico tend to have higher mercury than those from the Atlantic coast. Due to this variability, Spanish mackerel is often considered a moderate-mercury fish. Vulnerable groups should limit or avoid this species, particularly if the origin is unknown.

Why Canned Mackerel is Generally Safe

Most canned mackerel is made from smaller, low-mercury species such as Atlantic mackerel, making it a safe choice for most people. Canned mackerel is a good source of omega-3 fatty acids and protein. Consumers should check sodium content for dietary reasons.

Comparison of Mackerel Species Mercury Levels

Based on data from organizations like the FDA and EPA, mercury levels vary significantly:


Mackerel Species	Average Mercury Level (PPM)	Relative Mercury Level	FDA/EPA Recommendation
Atlantic Mackerel	0.05	Low	Best Choice
Chub Mackerel	0.088	Low	Best Choice
Spanish Mackerel (Atlantic)	0.182	Moderate	Good Choice (Limit)
Spanish Mackerel (Gulf of Mexico)	0.454	High	Limit/Avoid
King Mackerel	0.730	Highest	Avoid

The Risks of High Mercury Exposure

While the body can eliminate small amounts of mercury, high exposure can harm the neurological system, especially in infants and children. Symptoms can include tingling and coordination issues. Moderate fish consumption for adults typically poses minimal risk, but knowing which species to choose is important.

The Health Benefits of Mackerel

Mackerel is a nutritious food, rich in omega-3 fatty acids, particularly EPA and DHA. These fatty acids are beneficial for heart health, reducing inflammation and potentially lowering blood pressure. Omega-3s also support brain function. Mackerel also provides Vitamin B12, selenium, and protein.

How to Choose the Right Mackerel

When selecting mackerel, look for specific species names on packaging or ask your fishmonger. Prioritize smaller, low-mercury options like Atlantic mackerel. The FDA and EPA offer comprehensive guidelines on fish consumption for all individuals, including vulnerable groups. For official dietary advice, you can consult the FDA's advice on eating fish.

Conclusion

Whether mackerel is "full of mercury" depends on the species. Smaller species like Atlantic mackerel are low in mercury and safe for frequent consumption, offering numerous health benefits. Larger, predatory species like king mackerel have high mercury levels and should be avoided, especially by at-risk individuals. Making informed choices about the type of mackerel you eat allows you to enjoy this nutritious fish safely.

Frequently Asked Questions

No, most canned mackerel is made from Atlantic or chub mackerel, which are low-mercury species. This makes canned mackerel a safe and healthy option for regular consumption.

The king mackerel, a large predatory species, has the highest mercury content among mackerel species. For this reason, the FDA recommends that at-risk populations avoid it entirely.

Yes, but only certain kinds. Pregnant women should strictly avoid high-mercury king mackerel but can safely eat low-mercury Atlantic or chub mackerel as part of their recommended fish intake.

When purchasing, it is important to read the label. If buying fresh, ask the fishmonger. Many canned products will specify "Atlantic mackerel" on the packaging to indicate the low-mercury variety.

For most healthy individuals, it is safe to eat Atlantic mackerel two to three times per week. The American Heart Association recommends at least two servings of oily fish like mackerel weekly for heart health.

Atlantic mackerel generally has slightly less mercury than canned light tuna. Both are on the FDA's 'Best Choices' list for low-mercury fish.

Spanish mackerel has moderate mercury levels, which can vary by location. The FDA advises limiting consumption of this species, especially if caught in certain areas like the Gulf of Mexico, where mercury is higher.