Avoiding Mercury Levels in Fish: The List for Choosing Safe and Healthy Seafood

mercury levels in fish photo

Methylmercury is toxic to the human body, specifically the brain, kidneys, liver, heart, and nervous system. While mercury itself is a naturally occurring element, human industrial activity–coal-fired electricity generation, for example–pollutes the air and then finds its way into lakes, streams, and the ocean. Fish feed on other fish that are contaminated with mercury, that’s why mercury levels in large fish tend to be higher. This guide uses data from NRDC, EWG, and EPA.

People who aren’t aware of mercury levels in fish and are exposed to too much, can suffer from a wide array of symptoms including sleep disturbance, headaches, fatigue, memory and concentration problems, and neuropathy. But mercury is most dangerous to the developing fetus because it can cause lasting problems in infants and children including reduced intelligence, memory and concentration issues, and hyperactivity.

Low Mercury

If you’re not sure about a certain fish not found on this list, checkout the NRDC Mercury Calculator and their overall list. Fish that are overfished should also be avoided and are listed below.

Anchovies
Butterfish
Catfish
Clams
Crabs
Flounder (overfished)
Atlantic Haddock
Herring
Oysters
Mullet
Canned Salmon
Fresh Salmon (Choose wild salmon because farmed salmon may be contaminated with PCBs and other chemicals.)
Sardines
Scallops
Shrimp (Check the fishing method because unsustainable fishing methods, often used to catch shrimp, can cause major environmental damage.)
Sole
Squid
Tilapia
Trout
Whitefish
Whiting

Moderate Mercury (6 servings or less per month)

Bass
Carp
Atlantic or Pacific Halibut
Lobster
Mahi Mahi
Monkfish
Perch
Canned Light Tuna
Skipjack Tuna

High Mercury (3 servings or less per month)

Grouper (overfished)
Spanish or Gulf Mackerel
Sea Bass (overfished)
Albacore Canned Tuna
Yellowfin Tuna (overfished)

Highest Mercury (Avoid. Mostly all of the highest mercury fish are also overfished)

King Mackerel
Marlin
Orange Roughy
Shark
Swordfish
Tilefish
Bigeye or Ahi Tuna

However, while mercury levels in fish are important, Omega 3 fatty acids are also important for the developing fetus and for heart and brain health in adults, it’s important to choose fish that are high in omega 3 fatty acids and low in mercury. It’s not that you can’t eat fish that are low in omegas and low in mercury, but if you’re in search of omegas, here’s how to get your fill.

High In Omega 3 Fatty Acids, Low in Mercury

Anchovies
Wild Salmon
Whitefish
Sardines
Herring
Freshwater Trout

Related on Organic Authority

Mercury Levels in Fish More than Double What Some Labels Say, Finds Study

5 Tips to Detoxify Your Body of Mercury and Heavy Metal Poisoning

Are You Worried About Mercury in Fish? This Graphic Can Help

Image: Pedro Angelini

Sara Novak
Sara Novak

Sara Novak is an independent journalist who reports on health, science, yoga, and travel. She was a writer for Discovery Communications from 2006-2013 and her work has been featured on Discovery Health, Popular Science, TLC, Animal Planet, What to Expect, TreeHugger, and many more. She’s also a certified yoga teacher. When she's not churning away on her laptop, she can be found atop her yoga mat or walking the beach with her husband, baby boy, and two lovable cocker spaniels.