Mercury in Fish: Safe Consumption Guide Chart

Author: Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 2015/06/15 - Updated: 2026/06/02
Publication Type: Informative

Contents: Synopsis - Definition - Introduction - Main - Insights, Updates - Related Publications

Synopsis: This informational resource provides comprehensive data on mercury contamination levels across fish and shellfish species, drawing from U.S. government scientific testing conducted by the Department of the Interior across 291 streams nationwide. The information proves particularly valuable for pregnant women, nursing mothers, young children, seniors, and individuals with disabilities who may be more vulnerable to mercury's neurological effects, which include sensory impairment affecting vision, hearing, and speech, along with coordination difficulties.

The chart categorizes fish into four distinct mercury-level groups - ranging from species with less than 0.09 parts per million (like anchovies, salmon, and shrimp) to those exceeding 0.5 ppm (including swordfish, shark, and king mackerel) - while explaining that mercury was detected in every fish tested, even from isolated rural waterways. What makes this resource authoritative is its foundation in EPA and FDA guidelines, alongside detailed scientific data showing mean mercury concentrations and the biological reality that over 95 percent of consumed methylmercury enters the bloodstream and can penetrate cells in any tissue or organ, making informed fish selection critical for health management.

At a Glance

• 1 - A 6-ounce serving of salmon has only about 4 micrograms of mercury, compared with roughly 60 micrograms for the same portion of canned albacore tuna and 170 micrograms for swordfish.
• 2 - Of the fish sampled across the country, 25% carried mercury levels above the EPA's safety threshold for people who eat fish regularly.
• 3 - Mercury levels in the northern Pacific Ocean have climbed about 30% over the past 20 years and are projected to rise another 50% by 2050 as industrial emissions grow.

Topic Definition: Mercury in Fish

Mercury in fish refers to the buildup of the toxic heavy metal mercury, mostly in its organic form methylmercury, within the bodies of fish and shellfish. Mercury enters waterways from natural sources like volcanoes and weathering rock as well as human activities such as coal burning and mining, and once in the water, bacteria convert it into methylmercury that works its way up the food chain. Through a process called biomagnification, the largest, longest-lived predators at the top of the chain, such as shark, swordfish, king mackerel, and tilefish, end up with the highest concentrations, while small species like sardines, shrimp, and scallops carry very little. This matters for human health because methylmercury is readily absorbed when people eat seafood and can cross both the blood-brain barrier and the placenta, making it especially risky for pregnant women, nursing mothers, and young children whose nervous systems are still developing. Because fish also deliver valuable nutrients like omega-3 fatty acids and protein, the practical aim is not to avoid fish altogether but to choose lower-mercury species and limit how often higher-mercury ones are eaten.

Introduction

The U.S. FDA recommends eating 8 - 12 ounces of fish low in mercury per week. Fish contain vital nutrients including omega 3 fatty acids, protein, vitamins, and minerals such as iron. These nutrients are essential, particularly for pregnant moms, as they foster healthy fetal, infant, and childhood development. However, some types of fish contain a lot higher mercury levels than others.

Mercury is defined as a chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). Mercury can be absorbed through the skin and mucous membranes and mercury vapors can be inhaled, so containers of mercury are securely sealed to avoid spills and evaporation. The most toxic forms of mercury are its organic compounds, such as dimethylmercury and methylmercury. Mercury can cause both chronic and acute poisoning.

Mercury poisoning (also known as hydrargyria or mercurialism) is a type of metal poisoning and a medical condition caused by exposure to mercury or its compounds. Symptoms typically include sensory impairment (vision, hearing, speech), disturbed sensation and a lack of coordination. The type and degree of symptoms exhibited depend upon the individual toxin, the dose, and the method and duration of exposure.

Main Content

US government scientists tested fish in 291 streams around the country for mercury contamination. They found mercury in every fish tested, according to the study by the U.S. Department of the Interior. They found mercury even in fish of isolated rural waterways. 25% of the fish tested had mercury levels above the safety levels determined by the U.S. Environmental Protection Agency for people who eat the fish regularly.

Fish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organic compound of mercury. Mercury is known to bio-accumulate in humans, so bio-accumulation in seafood carries over into human populations, where it can result in mercury poisoning. The presence of mercury in fish can be a particular health concern for women who are or may become pregnant, nursing mothers, and young children.

Mercury levels in the northern Pacific Ocean have risen about 30 percent over the past 20 years and are expected to rise by 50 percent more by 2050 as industrial mercury emissions increase, according to a 2009 study led by researchers at the U.S. Geological Survey and Harvard University. When you eat seafood containing methylmercury, more than 95 percent is absorbed, passing into your bloodstream. It can move throughout your body, where it can penetrate cells in any tissue or organ.

In comments submitted to federal health officials, a group of scientists and policy analysts pointed out that a 6-ounce serving of salmon contains about 4 micrograms of mercury vs. 60 micrograms for the same portion of canned albacore tuna - and 170 micrograms for swordfish.

The list below shows the amount of various types of fish that a woman who is pregnant or planning to become pregnant can safely eat, according to the Environmental Protection Agency (EPA).

Jump-to:

Least Mercury - Less than 0.09 Parts Per Million (PPM)

Enjoy these fish with the least amount of mecury content:

Moderate Mercury - From 0.09 to 0.29 Parts Per Million (PPM)

Eat six servings or less per month:

High Mercury - From 0.3 to 0.49 Parts Per Million (PPM)

Eat three servings or less per month:

Highest Mercury - More than 0.5 Parts Per Million (PPM)

Avoid eating these fish types:

Navigating Mercury Risks in Fish and Shellfish Consumption

• (i) - Indicates only methylmercury was analyzed - Other results are for total mercury.
• (ii) - Data not available.
• (iii) - Below detection level (0.01ppm).

Insights, Analysis, and Developments

Author Credentials: Ian is the founder and Editor-in-Chief of Disabled World, a leading resource for news and information on disability issues. With a global perspective shaped by years of travel and lived experience, Ian is a committed proponent of the Social Model of Disability-a transformative framework developed by disabled activists in the 1970s that emphasizes dismantling societal barriers rather than focusing solely on individual impairments. His work reflects a deep commitment to disability rights, accessibility, and social inclusion. To learn more about Ian's background, expertise, and accomplishments, visit his full biography.