Which tuna has the highest mercury content?

December 9, 2025 •

4 min read

According to the U.S. Food and Drug Administration (FDA), bigeye tuna contains the highest levels of mercury among commonly consumed tuna species, with some samples recorded as high as 1.816 ppm. When considering which tuna has the highest mercury content, it's clear that the largest, longest-lived fish pose the highest risk of accumulation.

Quick Summary

Bigeye tuna typically contains the highest mercury levels due to bioaccumulation. Albacore and yellowfin also have higher content than smaller skipjack, the lowest-mercury option.

Key Points

Bigeye Tuna is Highest: Bigeye tuna, often used in sushi, contains the most mercury due to its large size and deep-water foraging habits.
Albacore Contains More Mercury than Light Tuna: Canned white or albacore tuna has nearly three times the mercury of canned light tuna, which is mostly skipjack.
Choose Skipjack for Lowest Mercury: Smaller, shorter-lived skipjack tuna is the safest option with the lowest mercury levels, commonly labeled as canned light tuna.
Bioaccumulation is the Cause: Mercury levels build up through the food chain, so larger, older predatory fish like bigeye and albacore accumulate more over time.
Limit High-Mercury Fish for Vulnerable Groups: Pregnant or nursing women and young children should avoid high-mercury tuna like bigeye and limit albacore, following specific FDA guidelines.
Diversify Your Seafood: To minimize mercury risk, incorporate a variety of low-mercury seafood options like salmon, sardines, and shrimp into your diet.

Understanding Mercury Contamination in Tuna

Mercury is a naturally occurring element, but industrial activities have increased its concentration in the environment. When mercury enters the aquatic ecosystem, bacteria convert it into a potent neurotoxin called methylmercury. This compound is then absorbed by small aquatic organisms and enters the food web.

The process of bioaccumulation explains why mercury levels are higher in certain types of tuna. As larger, predatory fish consume smaller contaminated fish, the methylmercury accumulates and concentrates in their tissue. This means that the biggest, oldest predators at the top of the food chain, including some tuna species, will have the highest mercury concentrations.

How Bioaccumulation Affects Tuna Species

The size and lifespan of different tuna species are key determinants of their mercury content. A long life and a position high on the food chain allow for significant accumulation over time. For instance, bigeye and bluefin are large, long-lived predators, which explains their elevated mercury levels. In contrast, the smaller skipjack tuna has a shorter lifespan, resulting in less time for mercury to build up.

Which Tuna Has the Highest Mercury Content?

Bigeye Tuna

Found primarily in sushi and sashimi, bigeye tuna is consistently identified as the species with the highest mercury content. FDA data indicates an average mercury concentration of 0.689 ppm, with levels capable of reaching over 1.8 ppm in some individuals. This is largely due to their size and foraging habits, as they dive deeper into the water column where methylmercury levels are more concentrated. Given these high levels, the FDA recommends avoiding bigeye tuna, especially for vulnerable groups like pregnant women and children.

Albacore Tuna

Often sold as "white" tuna, albacore has the next highest mercury levels, significantly more than skipjack. The FDA reports that canned albacore has an average of 0.350 ppm of mercury, making it a "Good Choice" rather than a "Best Choice". Fresh or frozen albacore has a slightly higher average at 0.358 ppm. Its larger size and longer lifespan contribute to this elevated concentration.

Yellowfin Tuna

Also known as "ahi," yellowfin tuna has mercury levels comparable to albacore. Often sold as steaks or used in sushi, fresh or frozen yellowfin contains an average of 0.354 ppm of mercury. Its classification as a "Good Choice" by the FDA means consumption should be limited, particularly for sensitive populations.

Skipjack Tuna

This smaller species is the primary source of canned "light" tuna and boasts the lowest mercury levels among the popular tuna types. With an average of 0.126 ppm in canned products, skipjack is considered a "Best Choice" by the FDA, allowing for more frequent consumption.

Mercury Content Comparison Table


Tuna Species	Average Mercury (ppm)	Mercury in Canned Version (ppm)	FDA Consumption Category
Bigeye	0.689	Not applicable	Choices to Avoid
Albacore	0.358	0.350	Good Choices
Yellowfin	0.354	Not typically canned as "light"	Good Choices
Skipjack	0.144	0.126	Best Choices

How to Make Safer Tuna Choices

Making informed choices can help mitigate mercury exposure while still enjoying the nutritional benefits of fish. The following guidelines are critical for both adults and children:

Prioritize Low-Mercury Fish: Include plenty of low-mercury fish in your diet, such as salmon, sardines, and anchovies.
Choose Wisely: When buying tuna, opt for canned light (skipjack) over canned white (albacore). For fresh or frozen options, choose skipjack if available.
Moderation is Key: No matter the type, consuming tuna in moderation is crucial. Following FDA/EPA guidelines for serving sizes can help manage overall intake.
Be Aware of Consumption Guidelines: The FDA and EPA provide specific recommendations for different population groups. For example, pregnant women should limit their intake to 8–12 ounces per week of fish from the "Best Choices" category and avoid those in the "Choices to Avoid" category.

Beyond Tuna: Low-Mercury Seafood Alternatives

For those looking to reduce their mercury intake, several nutritious and low-mercury seafood options are available:

Salmon (canned or fresh)
Shrimp
Catfish
Sardines
Anchovies
Tilapia

Conclusion

While many tuna varieties offer significant nutritional benefits, the risk of mercury contamination is a valid concern that varies by species. Bigeye tuna consistently has the highest mercury content, followed by albacore and yellowfin. For those seeking to minimize their mercury exposure, the smaller and shorter-lived skipjack tuna, found in canned light products, is the safest bet. By understanding these differences and following established guidelines, consumers can enjoy the health benefits of seafood while making conscious decisions to reduce their mercury intake. It is always wise to consult the latest FDA and EPA advice on fish consumption to stay informed. For the most up-to-date information, refer to the FDA and EPA's Advice About Eating Fish.

Frequently Asked Questions

Bigeye tuna generally contains the highest levels of mercury among the different tuna species due to its larger size and longer lifespan, followed by albacore tuna.

Canned light tuna is typically made from smaller, younger skipjack tuna, which is the species with the lowest mercury content.

Yes, canned white or albacore tuna has a significantly higher mercury concentration than canned light (skipjack) tuna. Health experts recommend limiting its consumption.

Larger, longer-lived predatory fish accumulate more methylmercury in their bodies over time through a process called bioaccumulation. Smaller fish have less time to accumulate mercury.

To reduce your mercury intake, choose lower-mercury options like canned light (skipjack) tuna, consume tuna in moderation, and include a variety of other low-mercury fish in your diet.

Pregnant women and young children should follow specific guidelines. They are advised to avoid high-mercury fish like bigeye tuna and should limit other types, opting for canned light tuna from the "Best Choices" category.

No, cooking or draining tuna will not reduce its mercury content. The mercury is bound within the muscle tissue of the fish, so these preparation methods are ineffective.

Fresh tuna steak, which can be bigeye or yellowfin, generally has higher mercury levels than canned light tuna, which is usually skipjack. The canning process does not remove mercury.