Which seafood does not have mercury?

November 20, 2025 •

2 min read

According to the FDA, almost all fish and shellfish contain trace amounts of methylmercury. Therefore, the concept of seafood without mercury is a misnomer, however, it is possible to identify seafood with low levels that are safe for regular consumption.

Quick Summary

This guide lists low-mercury seafood options. The safest species are determined by size, diet, and lifespan. The accumulation of mercury is explained and advice is offered to reduce exposure, particularly for pregnant women and children. Salmon, sardines, and shellfish are key choices.

Key Points

Not all seafood is mercury-free: Trace amounts of methylmercury exist in almost all marine life due to environmental factors, making truly mercury-free seafood an impossibility.
Small, short-lived species are safest: The lowest mercury levels are found in smaller fish and shellfish that are lower on the food chain, such as sardines, anchovies, shrimp, and scallops.
Predatory fish have the most mercury: Larger, predatory, and longer-lived fish like shark, swordfish, and king mackerel accumulate the highest levels of mercury and should be limited or avoided.
Canned light tuna is a better choice: If consuming canned tuna, opt for canned light tuna (skipjack) over canned albacore, as it contains significantly less mercury.
Varying your seafood intake is key: Eating a diverse mix of seafood, particularly focusing on low-mercury options, helps to minimize overall mercury exposure.
Cooking does not remove mercury: Methylmercury binds to the fish's muscle tissue and cannot be removed by cooking or other preparation methods.

The Science of Mercury in Seafood

Mercury is a naturally occurring element. In water, bacteria transform it to methylmercury, which marine life absorbs. Some seafood have higher levels of mercury because of biomagnification. This occurs when small organisms absorb methylmercury, small fish eat these organisms, and larger predatory fish eat the smaller fish, concentrating mercury at each level. Large predatory fish, such as shark and swordfish, have the most mercury. Smaller, shorter-lived species have less.

Low-Mercury Seafood Options

Since no seafood is entirely mercury-free, select options with the lowest levels. Small, fast-growing fish and shellfish are generally safest.

Best Choices for Minimizing Mercury

Salmon: A low-mercury source of omega-3s.
Sardines and Anchovies: Small, low on the food chain, with minimal mercury.
Shellfish: Shrimp, clams, scallops, and oysters have very low mercury due to their diet.
Pollock: A common, mild white fish with low mercury.
Tilapia: Farm-raised with low mercury, though source is important.
Catfish: A low-mercury choice, particularly farmed.
Cod and Haddock: Popular white fish with low mercury content.
Trout: Freshwater trout, like rainbow trout, is a low-mercury option.
Canned Light Tuna: Skipjack tuna in canned light varieties has significantly less mercury than albacore.

Comparison of Seafood Mercury Levels

This table categorizes seafood by typical mercury content.


Seafood Type	Mercury Level (Typical)	Consumer Guidance
Shark	High	Avoid for sensitive groups; limit for others.
Swordfish	High	Avoid for sensitive groups; limit for others.
King Mackerel	High	Avoid for sensitive groups; limit for others.
Tilefish (Gulf of Mexico)	High	Avoid for sensitive groups; limit for others.
Bigeye Tuna	High	Avoid for sensitive groups; limit for others.
Albacore Tuna	Moderate	Limit intake, especially for sensitive groups.
Halibut	Moderate	Consume in moderation.
Canned Light Tuna	Low	Safe for regular consumption.
Salmon	Low	Safe for regular consumption.
Sardines	Low	Safe for regular consumption.
Shrimp	Low	Safe for regular consumption.
Scallops	Very Low	Safe for regular consumption.
Catfish	Low	Safe for regular consumption.
Pollock	Low	Safe for regular consumption.

How to Minimize Mercury Exposure

Besides selecting low-mercury options, consider these tips:

Vary your diet: Include different low-mercury seafood and protein sources.
Check local advisories: For self-caught fish, consult local environmental agencies.
Mind portion sizes: Most adults can have 2-3 servings of low-mercury seafood weekly. Sensitive groups have specific limits.
Choose canned light tuna: Opt for "chunk light" over "albacore".

Conclusion

While mercury-free seafood doesn't exist, many options have low, safe levels for regular eating. Prioritize smaller, shorter-lived species like salmon, sardines, and shellfish for nutritional benefits with minimal risk. Varying your seafood, minding portions, and choosing low-mercury types are key. Consult FDA/EPA guidelines, especially for pregnant women and children.

Disclaimer: This article provides general information and is not a substitute for professional medical advice. Always consult with a healthcare provider for personalized dietary recommendations.

Authoritative Source: For more detailed guidance, the U.S. Food and Drug Administration provides comprehensive advice on mercury levels in commercial fish and shellfish: https://www.fda.gov/food/consumers/advice-about-eating-fish

Frequently Asked Questions

No seafood is completely free of mercury. Due to widespread environmental contamination, nearly all fish and shellfish contain at least trace amounts of methylmercury. However, many options have such low levels that they are considered safe for regular consumption.

The highest mercury levels are typically found in large, long-lived predatory fish at the top of the food chain, such as shark, swordfish, king mackerel, and Gulf of Mexico tilefish. These species should be limited or avoided, especially by sensitive populations.

It depends on the type. Canned 'light' tuna, usually skipjack, has low mercury levels and is a 'best choice' according to the FDA. However, canned 'white' or albacore tuna has higher mercury levels and should be consumed in moderation, particularly by vulnerable groups.

Yes, shrimp is a very safe, low-mercury seafood choice. Since they are lower on the food chain and relatively short-lived, they do not accumulate significant levels of mercury.

Research suggests that farmed fish, such as some salmon, may have slightly lower mercury levels than their wild-caught counterparts. This is because their diet is more controlled. However, mercury levels in most low-mercury species are safe whether wild-caught or farmed.

No, cooking fish does not remove mercury. The methylmercury is bound to the fish's muscle tissue, and the metal will remain in the fish regardless of the preparation method, whether grilled, baked, or raw.

According to the FDA, most people can safely eat two to three servings (8 to 12 ounces) per week of a variety of fish that are lower in mercury, such as salmon, shrimp, and tilapia.

Not necessarily. Mercury levels depend more on the fish's size, age, and diet rather than whether it comes from freshwater or saltwater. Local advisories are crucial for freshwater fish, as specific waterways may have higher contamination.

Yes, it is safe and encouraged for pregnant women to eat fish that is low in mercury. The FDA recommends up to 12 ounces per week of low-mercury varieties, as the omega-3 fatty acids are beneficial for fetal brain and eye development.

The primary reason is bioaccumulation and biomagnification, where mercury becomes more concentrated as it moves up the food chain. Larger, older fish that prey on smaller fish have had more time to accumulate higher mercury levels.