Mercury in Fish: Safe Consumption Guide & Chart

Author: Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 2015/06/15 - Updated: 2025/12/01
Publication Type: Informative
Category Topic: Calculators - Charts - Related Publications

Page Content: Synopsis - Introduction - Main - Insights, Updates

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 - Disabled World (DW).

Definition: Mercury: Mercury is a naturally occurring heavy metal element that exists in several forms throughout the environment, including elemental mercury (the silvery liquid once common in thermometers), inorganic mercury compounds, and organic methylmercury, which is the form that accumulates in fish and poses the greatest risk to human health. Released into the air from volcanic eruptions, weathering of rocks, and human activities like coal burning and mining, mercury eventually settles into water bodies where bacteria convert it to methylmercury, which then concentrates up the food chain as larger predatory fish consume smaller organisms. When humans eat contaminated fish, methylmercury is absorbed into the bloodstream and can cross both the blood-brain barrier and the placenta, making it particularly dangerous for developing fetuses and young children whose nervous systems are still forming. Even low-level exposure over time can affect cognitive function, memory, attention, language skills, and fine motor coordination, with prenatal exposure linked to developmental delays and learning disabilities. While the body can eliminate mercury naturally, the process is slow, and regular consumption of high-mercury fish can lead to accumulation faster than the body can clear it, which is why health agencies recommend limiting intake of species like shark, swordfish, and king mackerel that sit atop the aquatic food chain and harbor the highest concentrations.

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.

This diagram illustrates how mercury pollution accumulates in aquatic food chains through biomagnification. At the top, pollution sources are shown including a volcano, coal plant, and mine releasing mercury into the atmosphere and waterways, with dotted arrows showing methylmercury entering the aquatic ecosystem. In the water below, a food chain is depicted with arrows showing energy flow from small organisms (krill) to medium fish (salmon, pollock, oyster) to larger predatory fish (trout, tuna, albacore) and finally to apex predators (shark, pike, halibut). At the bottom, three thermometer-style indicators show EPA consumption advice based on mercury levels: large predatory fish have the highest mercury concentrations and should be eaten only a few times per month, medium fish like tuna can be eaten a few times per week, and smaller organisms like krill and shellfish have the lowest mercury levels and can be consumed unlimited.

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:

Fish with Least Mercury Levels
Fish with Moderate Mercury Levels
Fish with High Mercury Levels
Fish with Highest Mercury Levels

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

Enjoy these fish with the least amount of mecury content:

Anchovies
Butterfish
Catfish
Clam
Crab (Domestic)
Crawfish/Crayfish
Croaker (Atlantic)
Flounder
Haddock (Atlantic)
Hake
Herring
Mackerel (N. Atlantic, Chub)
Mullet
Oyster
Perch (Ocean)
Plaice
Pollock
Salmon (Canned)
Salmon (Fresh)
Sardines
Scallops
Shad (American)
Shrimp
Sole (Pacific)
Squid (Calamari)
Tilapia
Trout (Freshwater)
Whitefish
Whiting

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

Eat six servings or less per month:

Bass (Striped, Black)
Carp
Cod (Alaskan)
Croaker (White Pacific)
Halibut (Atlantic)
Halibut (Pacific)
Jacksmelt (Silverside)
Lobster
Mahi Mahi
Monkfish
Perch (Freshwater)
Sablefish
Skate
Snapper
Tuna (Canned chunk light)
Tuna (Skipjack)
Weakfish (Sea Trout)

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

Eat three servings or less per month:

Bluefish
Grouper
Mackerel (Spanish, Gulf)
Sea Bass (Chilean)
Tuna (Canned Albacore)
Tuna (Yellowfin)

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

Avoid eating these fish types:

Mackerel (King)
Marlin
Orange Roughy
Shark
Swordfish
Tilefish
Tuna (Bigeye, Ahi)

Navigating Mercury Risks in Fish and Shellfish Consumption

Mercury Levels in Fish/Shellfish
Species	Mean (ppm)	Std dev (ppm)	Median (ppm)	Comments	Trophic level	Max age (yrs)
Tilefish - Gulf of Mexico	1.123	(ii)	(ii)	Mid-Atlantic tilefish has lower mercury level.	3.6	35
Swordfish	0.995	0.539	0.870		4.5	15
Shark	0.979	0.626	0.811
Mackerel - King	0.730	(ii)	(ii)		4.5	14
Tuna - Bigeye	0.689	0.341	0.560	Fresh/Frozen	4.5	11
Orange Roughy	0.571	0.183	0.562		4.3	149
Marlin*	0.485	0.237	0.390		4.5
Mackerel - Spanish	0.454	(ii)	(ii)	Gulf of Mexico	4.5	5
Grouper	0.448	0.278	0.399	All Species	4.2
Tuna	0.391	0.266	0.340	All Species, Fresh/Frozen
Bluefish	0.368	0.221	0.305		4.5	9
Sablefish	0.361	0.241	0.265		3.8	94
Tuna - Albacore	0.358	0.138	0.360	Fresh/Frozen	4.3	9
Patagonian Toothfish	0.354	0.299	0.303	AKA Chilean Sea Bass	4.0	50+
Tuna - Yellowfin	0.354	0.231	0.311	Fresh/Frozen	4.3	9
Tuna - Albacore	0.350	0.128	0.338	Canned	4.3	9
Croaker White	0.287	0.069	0.280	Pacific	3.4
Halibut	0.241	0.225	0.188		4.3
Weakfish	0.235	0.216	0.157	Sea Trout	3.8	17
Scorpionfish	0.233	0.139	0.181
Mackerel - Spanish	0.182	(ii)	(ii)	South Atlantic	4.5
Monkfish	0.181	0.075	0.139		4.5	25
Snapper	0.166	0.244	0.113
Bass	0.152	0.201	0.084	Striped, Black, Black Sea	3.9
Perch	0.150	0.112	0.146	Freshwater	4.0
Tilefish - Atlantic	0.144	0.122	0.099		3.6	35
Tuna - Skipjack	0.144	0.119	0.150	Fresh/Frozen	3.8	12
Buffalofish	0.137	0.094	0.120
Skate	0.137	(ii)	(ii)
Tuna	0.128	0.135	0.078	All Species, Canned, Light
Perch - Ocean(i)	0.121	0.125	0.102
Cod	0.111	0.152	0.066		3.9	22
Carp	0.110	0.099	0.134
Lobster - American	0.107	0.076	0.086
Sheephead - California	0.093	0.059	0.088
Lobster - Spiny	0.093	0.097	0.062
Whitefish	0.089	0.084	0.067
Mackerel - Chub	0.088	(ii)	(ii)	Pacific	3.1
Herring	0.084	0.128	0.048		3.2	21
Jacksmelt	0.081	0.103	0.050		3.1
Hake	0.079	0.064	0.067		4.0
Trout	0.071	0.141	0.025	Freshwater
Crab	0.065	0.096	0.050	Blue, King, Snow
Butterfish	0.058	(ii)	(ii)		3.5
Flatfish(i)	0.056	0.045	0.050	Flounder, Plaice, Sole
Haddock	0.055	0.033	0.049	Atlantic
Whiting	0.051	0.030	0.052
Mackerel - Atlantic	0.050	(ii)	(ii)
Croaker - Atlantic	0.065	0.050	0.061
Mullet	0.050	0.078	0.014
Shad - American	0.039	0.045	0.045
Crayfish	0.035	0.033	0.012
Pollock	0.031	0.089	0.003
Catfish	0.025	0.057	0.005		3.9	24
Squid	0.023	0.022	0.016
Salmon(i)	0.022	0.034	0.015	Fresh/Frozen
Anchovies	0.017	0.015	0.014		3.1
Salmon(i)	0.014	0.021	0.010	Canned
Sardine	0.013	0.015	0.010		2.7
Tilapia(i)	0.013	0.023	0.004
Oyster	0.012	0.035	(iii)
Clam(i)	0.009	0.011	0.002
Shrimp(i)	0.009	0.013	0.001			6.5
Scallop	0.003	0.007	(iii)

(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

Editorial Note: The stark reality that mercury contamination exists in every tested fish species nationwide underscores an environmental challenge that transcends individual choice, yet the variation in contamination levels - from 0.003 ppm in scallops to over 1.1 ppm in Gulf of Mexico tilefish - demonstrates that informed selection remains a powerful tool for minimizing risk while still obtaining the vital omega-3 fatty acids, protein, and minerals that fish provide. As ocean mercury levels continue rising due to industrial emissions, with projections showing a 50 percent increase by 2050, this data becomes not just a dietary guide but a snapshot of our changing relationship with marine resources and the ongoing responsibility to balance nutritional benefits against environmental realities that affect everyone, particularly those whose health vulnerabilities demand extra vigilance - Disabled World (DW).

Ian C. Langtree 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.