What is the cleanest fish to eat in the world? Your guide to low-mercury and sustainable choices

According to the Food and Drug Administration (FDA), many fish contain low levels of mercury, but selecting the right options is key. For health-conscious consumers, knowing what is the cleanest fish to eat in the world involves understanding factors beyond just taste, including contaminants and sustainable sourcing.

Quick Summary

This article explores the concept of 'clean' fish, focusing on low-mercury content and sustainable sourcing. It provides a guide to the safest and most nutritious fish and shellfish, advises which to avoid, and offers a comparison of wild-caught versus farmed varieties.

Key Points

• No Single 'Cleanest' Fish: The term 'cleanest' refers to a category of fish with low contaminant levels, particularly mercury, not a single species.

• Small Fish, Lower Mercury: Smaller, shorter-lived fish like sardines, anchovies, and Atlantic mackerel are consistently low in mercury because they are lower on the food chain.

• Wild Alaskan Salmon is a Top Pick: Wild Alaskan salmon is known for its high omega-3 content, low mercury, and sustainable fishery management.

• Sourcing Matters: Consider sourcing (wild-caught vs. farmed) and look for sustainability certifications to make an informed choice.

• Avoid High-Mercury Fish: Limit or avoid large predatory fish such as king mackerel, swordfish, shark, and certain tuna species due to higher mercury concentration.

• Beneficial for Health: Low-mercury fish are packed with essential nutrients like omega-3s, high-quality protein, and vitamins D and B12.

• Vulnerable Groups Need Extra Caution: Pregnant women, nursing mothers, and young children should be especially careful to avoid high-mercury species.

Understanding What Makes a Fish 'Clean'

When people ask what the cleanest fish to eat is, they are usually referring to options with the lowest levels of contaminants. The primary concern is methylmercury, a neurotoxin that can accumulate in fish over time. Larger, longer-lived predatory fish tend to have the highest mercury levels due to bioaccumulation, meaning they consume smaller fish that also contain mercury. Other potential contaminants include polychlorinated biphenyls (PCBs) and dioxins. Therefore, the 'cleanest' fish are typically smaller, shorter-lived species found in cleaner environments.

Mercury Levels and Bioaccumulation

Mercury from industrial pollution enters waterways and is converted into methylmercury by bacteria. This organic mercury is absorbed by aquatic life, and its concentration increases as it moves up the food chain. For this reason, big predators like swordfish and sharks are known to contain high levels of mercury, while smaller fish like sardines and anchovies, which are lower on the food chain, have minimal amounts. It is crucial for vulnerable populations, including pregnant women, nursing mothers, and young children, to limit their intake of high-mercury fish.

The Importance of Sustainable and Responsible Sourcing

Beyond contaminants, the 'cleanliness' of a fish is also influenced by how it is sourced. The debate over wild-caught versus farmed fish involves considering different environmental impacts and potential impurities. Organizations like the Monterey Bay Aquarium's Seafood Watch and the Aquaculture Stewardship Council (ASC) provide guidance on the most sustainable options.

The Cleanest Fish to Eat: Best Choices

Based on mercury levels and sourcing, a number of fish and shellfish consistently rank as the cleanest and healthiest choices. These species are typically rich in heart-healthy omega-3 fatty acids and provide high-quality protein and other essential nutrients.

• Sardines and Anchovies: These small, oily fish are very low in mercury and exceptionally high in omega-3s, calcium, and vitamin D. They are also a sustainable choice and often available canned. Canned versions can be an affordable way to get essential nutrients.
• Wild Alaskan Salmon: Known for its rich omega-3 content, wild Alaskan salmon is a well-managed fishery with low mercury levels. Sustainably caught varieties have minimal environmental impact.
• Rainbow Trout: Farmed rainbow trout, particularly from the U.S. or in indoor recirculating tanks, is a sustainable and low-mercury option. It is a great source of omega-3s, protein, and B vitamins.
• Pacific Cod: This lean, flaky white fish is another low-mercury, low-calorie choice. It's often found in well-managed fisheries, offering a substantial amount of protein with very little fat.
• Wild Alaska Pollock: As a sustainable and lean protein source, Wild Alaska Pollock has low mercury levels, making it a safe choice even for sensitive groups. It is commonly used in fish sticks and fast-food sandwiches.
• Tilapia: As a commercially farmed fish, U.S.-farmed tilapia is considered a low-mercury option and is identified as a 'Best Choice' by the FDA and EPA.
• Atlantic Mackerel: This species, not to be confused with the higher-mercury King Mackerel, is a good source of omega-3s and is a sustainable option when sourced responsibly.

Fish to Limit or Avoid Due to Contaminants

While many fish are healthy, some should be consumed sparingly due to higher levels of mercury. The FDA and EPA have specific warnings for these species.

• King Mackerel: A larger predatory fish with high mercury levels.
• Shark: A top predator with among the highest mercury content.
• Swordfish: Contains high levels of mercury and should be avoided or limited, especially by pregnant women and young children.
• Tilefish (Gulf of Mexico): This species has the highest mercury levels of any fish.
• Bigeye Tuna: Contains more mercury than canned light tuna and is listed as a 'Choice to Avoid'.

Wild-Caught vs. Farmed Fish: A Comparison

Choosing between wild-caught and farmed fish can be complex. While the initial instinct might be to choose wild, responsible aquaculture has come a long way. The best option depends on the specific species and farming practices.

Feature	Wild-Caught Fish	Farmed Fish
Mercury Levels	Varies by species and location; larger fish have higher levels.	Can be lower in mercury due to controlled feed.
Nutritional Profile	Reflects a natural diet; often higher in protein and certain minerals.	Consistent supply with higher overall fat content (including omega-3s and omega-6s) depending on feed.
Flavor and Texture	Varies greatly, often considered to have a more robust, natural flavor.	Milder and more consistent flavor; can be fattier and flakier.
Environmental Impact	Risks of overfishing; methods can cause bycatch and habitat damage.	Can cause pollution, disease spread, and potential use of antibiotics if not managed well. Highly efficient systems exist (e.g., land-based aquaculture).
Availability	Seasonal; availability depends on fishing yields and regulations.	Available year-round due to controlled production.

Making the Best Choice for Your Health

To confidently choose the cleanest fish, follow these steps:

1. Prioritize Small, Forage Fish: Incorporate smaller, shorter-lived species like sardines, anchovies, and Atlantic mackerel into your diet regularly. These are consistently low in mercury and nutrient-dense.
2. Opt for Low-Mercury Varieties: Look for species like wild Alaskan salmon, rainbow trout, and Pacific cod, which are known for their lower contaminant levels and are often sustainably sourced.
3. Check Sourcing: When purchasing farmed fish, seek out products with certifications from reputable organizations like the Aquaculture Stewardship Council (ASC) or refer to guides from the Monterey Bay Aquarium Seafood Watch.
4. Cook Smart: The nutritional benefits of fish can be maximized through healthy cooking methods like grilling, baking, or steaming, rather than deep-frying.
5. Heed Local Advisories: If you are consuming locally caught fish, check advisories from your state or local health department, as contaminant levels can vary by location.

Conclusion

There is no single "cleanest fish" that takes the title universally. Instead, the cleanest options are a category of fish characterized by low mercury levels, sustainable sourcing, and responsible handling. By choosing smaller, lower-in-the-food-chain fish like sardines, anchovies, and salmon, and being mindful of sourcing for larger fish, you can enjoy the significant health benefits of seafood while minimizing potential risks from contaminants. Making informed decisions based on this information is the best way to ensure you're consuming the cleanest and most nutritious fish available.

For more detailed information on specific species, consult the FDA's comprehensive guide on eating fish: Advice about Eating Fish.

Frequently Asked Questions

Which fish has the lowest mercury levels?

Sardines, anchovies, salmon, and wild Alaska pollock are among the fish with the lowest mercury levels. They are typically smaller and lower on the food chain.

Is tilapia a clean fish to eat?

Yes, U.S.-farmed tilapia is considered a low-mercury fish by the FDA and EPA and is identified as a 'Best Choice'. However, as with all farmed fish, sourcing should be considered.

What is the cleanest type of salmon to eat?

Wild Alaskan salmon, including sockeye and coho, is a top choice. It's known for its low mercury content and comes from well-managed, sustainable fisheries.

Should I choose wild-caught or farmed fish for the lowest contaminants?

The answer varies by species. For some, like rainbow trout, responsibly farmed options can have lower mercury. In other cases, wild-caught may be leaner and free of antibiotics. It is best to check sustainable seafood guides.

Which fish should I avoid completely due to mercury?

You should limit or avoid high-mercury fish like king mackerel, shark, swordfish, orange roughy, and tilefish from the Gulf of Mexico.

How often can I eat fish without worrying about mercury exposure?

The American Heart Association recommends eating two servings of nonfried fish, especially fatty fish, every week. The key is choosing low-mercury options for regular consumption.

Is canned tuna safe to eat, especially for pregnant women?

Canned light tuna is lower in mercury and is a 'Best Choice' option. However, canned albacore ('white') tuna has higher mercury and should be limited to one serving (6 oz) per week for pregnant women.