What Tins of Tuna Contain Mercury? A Guide to Types and Safety

November 27, 2025 •

4 min read

According to the EPA and FDA, almost all fish contain some traces of methylmercury, a neurotoxin that can accumulate over time. This is why not all tins of tuna contain mercury at the same levels; the amount depends heavily on the species of tuna, with larger, longer-lived fish carrying more.

Quick Summary

The quantity of mercury in canned tuna is directly related to the species, with larger predators like albacore possessing higher levels than smaller, faster-growing skipjack. Consumers can make informed choices by understanding the differences between 'white' and 'light' varieties and following recommended consumption limits to reduce exposure.

Key Points

Albacore (White) Tuna: Contains significantly higher mercury levels than light tuna due to being a larger, longer-lived species.
Light (Skipjack) Tuna: The safer choice for most, as it comes from smaller tuna species with naturally lower mercury content.
Biomagnification: Mercury builds up in tuna because they are predatory fish high on the food chain, accumulating mercury from the smaller fish they eat.
Sensitive Populations: Pregnant women, breastfeeding mothers, and young children are most vulnerable to mercury and should strictly follow consumption guidelines or consider avoiding tuna entirely.
Informed Choices: Reading labels to identify the tuna species and varying your seafood intake with other low-mercury fish are effective strategies for reducing exposure.
Safe Catch Brand: A notable brand, Safe Catch, tests every fish to guarantee mercury levels well below federal limits, offering a lower-risk option for all consumers.

Understanding Mercury and Tuna

Mercury is a naturally occurring element that enters the marine ecosystem through both natural sources, like volcanic activity, and human activities, such as industrial pollution and coal burning. Once in the water, bacteria convert it into a highly toxic organic form known as methylmercury. Fish absorb this compound, and it bioaccumulates, becoming more concentrated as it moves up the food chain. Predatory fish, such as tuna, sit high on this chain, meaning they consume smaller, contaminated fish, leading to a buildup of methylmercury in their own tissue.

Factors Influencing Mercury Levels

Several factors determine the level of mercury in a specific tuna, including:

Species: Different species of tuna have distinct lifespans and positions in the marine food web. The largest and longest-lived species, like bigeye and albacore, naturally accumulate more mercury than their smaller, faster-growing counterparts, such as skipjack.
Size and Age: Within the same species, older and larger fish have had more time to accumulate methylmercury, resulting in higher concentrations compared to smaller, younger fish.
Location: The mercury concentration in the water where a tuna was caught can also affect its mercury content. Areas with higher industrial pollution or different oceanic conditions can lead to variations, even within the same species.

Canned Tuna Varieties and Mercury Content

Canned tuna is primarily sourced from a few main species, and understanding which is which is key to managing mercury intake.

Light Tuna vs. White Tuna

This distinction is one of the most critical for consumers. Most canned 'light' tuna is made from skipjack, a smaller species with a shorter lifespan and, consequently, lower mercury levels. In contrast, canned 'white' tuna is almost exclusively albacore, a larger tuna with a higher mercury concentration. Some 'gourmet' or 'tonno' labels might contain larger yellowfin tuna, which can have mercury levels comparable to albacore.

Mercury Comparison in Common Canned Tuna

Here is a comparison of average mercury levels in different types of canned tuna, based on FDA data:


Tuna Type	Primary Species	Average Mercury (ppm)	FDA Consumption Category	Weekly Adult Serving Guideline (4-oz servings)
Canned Light Tuna	Skipjack	0.13	Best Choice	2–3 servings
Canned White Tuna	Albacore	0.35	Good Choice	1 serving
Yellowfin Tuna	Yellowfin	0.35	Good Choice	1 serving
Bigeye Tuna	Bigeye	0.69	Avoid	No recommendation for sensitive groups

Making Safe Choices: Reducing Mercury Exposure

Responsible consumption can mitigate the risks of methylmercury exposure while allowing you to enjoy the nutritional benefits of fish.

Practical Tips for Lowering Your Intake

Here are some steps you can take to minimize your mercury consumption from tuna:

Prioritize Light Tuna: Opt for canned light or skipjack tuna over albacore or white tuna. This is the simplest and most effective way to reduce mercury intake from canned tuna.
Vary Your Seafood Intake: The FDA and EPA recommend a varied diet of fish, including other low-mercury options like salmon, sardines, shrimp, and tilapia.
Choose Carefully for Sensitive Populations: Pregnant and breastfeeding women, young children, and women planning to become pregnant are most vulnerable to the effects of mercury and should be particularly careful. Some experts, including Consumer Reports, suggest these groups avoid tuna altogether due to the unpredictable spikes in mercury from can to can.
Consider Brands with Tested Fish: Some brands, such as Safe Catch, test every fish they use to ensure lower mercury levels. For consumers with concerns, seeking out these brands can provide greater peace of-mind.
Check Local Advisories: If consuming fresh or locally caught tuna, always check local advisories for any regional warnings.

Understanding Regulatory Advice

Regulatory bodies, such as the FDA and EPA, provide guidelines to help consumers balance the benefits of eating fish with the risks of mercury exposure. The advice is based on average mercury levels and assumes typical consumption patterns. For example, for canned light tuna, it's generally safe for most adults to have 2–3 servings per week, while canned white (albacore) is typically limited to one serving per week. However, it's important to remember that these are averages, and individual cans can vary.

Conclusion

While almost all tins of tuna contain mercury to some degree, the level is not uniform across all products. The key to mitigating health risks is to be an informed consumer. By understanding the difference between high-mercury albacore and low-mercury skipjack, and by choosing brands that prioritize testing and sustainable practices, you can enjoy the nutritional benefits of tuna safely and responsibly. Moderation and a varied diet of different fish species are the best strategies to ensure a healthy balance.

Visit the FDA's website for comprehensive advice on eating fish and shellfish.

Frequently Asked Questions

Canned white tuna, which is albacore, generally has the highest mercury levels. Bigeye tuna, often used in fresh sushi but sometimes canned as 'gourmet' or 'tonno', also contains high levels.

Canned light tuna, which is typically made from the smaller skipjack species, contains the lowest amount of mercury.

For most adults, the FDA recommends limiting canned white (albacore) tuna to one 4-ounce serving per week. For canned light (skipjack) tuna, 2 to 3 servings per week is generally considered safe.

Yes, mercury levels can vary significantly by brand and even from can to can within the same brand. Some brands, like Safe Catch, test every fish to guarantee lower levels.

No, draining the oil or water from canned tuna will not significantly reduce the mercury content, as methylmercury is bound to the fish's flesh, not the fluid.

High mercury exposure can affect the nervous system, potentially causing symptoms like memory loss, numbness, tremors, and impaired coordination. These risks are especially high for developing brains in fetuses and young children.

Due to the unpredictable variation of mercury levels in individual cans, some food safety experts, including Consumer Reports, advise pregnant women to avoid tuna entirely. The FDA, however, provides consumption guidelines for light and white tuna for pregnant women.