Mercury in Fish vs. Omega-3 Fatty Acids Health Benefits

Part 2 of 2

By Tim Fitzpatrick

[Dec. 2005]


But I'm pregnant and I love to eat fish.

The last scenario had women of childbearing age increasing fish consumption. As a result, a minor decrease in heart disease and mortality was seen. There was also a slight decrease in IQ, approximately .07 points per child.

Action Plans

The researchers agree that because of the nutritional value of fish, communicating risk efforts to women of childbearing age is paramount. It is important that they alter the type of fish they eat, rather than the amount. In addition, communicating this risk while maintaining or increasing fish consumption in other populations is ideal. The researchers go on to say that if somehow all adults, even women of childbearing age consumed eight ounces of salmon a week, annual heart disease would drop by nearly 20,000 cases. On top of that, eating this low methylmercury fish would contribute to a drop in nonfatal strokes by 4,000 and a 0.5 IQ point increase per child. In all likelihood, women of childbearing age will probably associate dangers of mercury in all fish and therefore decrease total fish consumption. If the elderly decrease their fish consumption, then the risk of heart disease and stroke, as noted in scenario three, would increase by 17%. To reach these conclusions, the researchers convened a panel of experts who measured QALY (Quality Adjusted Life Years). This mathematical model measures life years gained or lost due to the shifting consumption of fish and is used as a common metric to make the findings comparable. The researchers do admit that each scenario could be under or over estimated as it relates to actual numbers but they are confident of the fact that the trend does support their argument. The researchers couldn't overstate enough that risk managers need to be careful when issuing warnings about fish consumption.

Fish Sustainability and the Environment

Since it has been well reported that catches of wild fish are near or at maximum, in order to sustain this increase in fish consumption, aquaculture must be the vehicle. This method of production does have many potential environmental impacts. Shrimp farms have taken an enormous toll on coastal habitats with mangrove swamps being cleared for production in Africa and Southeast Asia. Aquaculture can also lead to water pollution as fish feces, uneaten food, and organic debris can cause algal blooms in nearby coastal and river waters. Methods are improving and new technologies are constantly being brought to light to combat this problem.

Reaction from the Fishing Industry

Based on the research findings, the U.S. Tuna foundation, in a press release, has called for an end to the "politicization" of the mercury issue stating that scaring people away from eating fish is detrimental to overall public health. They feel the benefits of including seafood into a healthy diet far outweigh any potential risk of methylmercury.


The public is concerned with high mercury levels in fish such as tuna, swordfish, and shark which could hinder prenatal brain development. However, eating fish is a part of a healthy lifestyle that includes the substantial benefits garnered from Omega-3 Fatty Acids. A diet void of Omega-3 Fatty Acids could be a risky adventure leading to heart disease and/or stroke. Pregnant women can consume low mercury level fish such as salmon and shrimp as an alternative to some of the high level species. Men and women in other age groups should be aware of the nutritional benefits of fish, specifically the role Omega-3 Fatty Acids play in disease prevention.

Editorial Comment from the Editor in Chief

Eating fish is an important part of our diet, unfortunately as a society we are polluting this important resource via mercury laden emissions from our coal fired power plants, factories, etc. (related article). People shouldn't be forced to choose between the health risks associated with toxins released via industrial pollution and the nutritional benefits from things like Omega-3 Fatty Acids in the foods we eat. As a society we must demand greater accountability with our industrial practices and take seriously the damage we are doing to our environment and our long term health.

Measured Mercury Concentrations in Various Species of Commercial Fish and Shellfish

SpeciesMercury Concentration (PPM)# SamplesSource of Data
Fish and Shellfish With Highest Levels of Mercury
MACKEREL KING0.73NA0.231.67213Gulf of Mexico Report 2000
SHARK0.990.83ND4.54351FDA Survey 1990-02
SWORDFISH0.970.860.103.22605FDA Survey 1990-02
TILEFISH (Gulf of Mexico)1.45NA0.653.7360NMFS Report 1978
Fish and Shellfish With Lower Levels of Mercury
ANCHOVIES0.04NAND0.3440NMFS Report 1978
BUTTERFISH0.06NAND0.3689NMFS Report 1978
CATFISH0.05NDND0.3122FDA Survey 1990-02
COD 0.110.10ND0.4220FDA Survey 1990-03
CRAB 30.06NDND0.6159FDA Survey 1990-02
CRAWFISH0.030.03ND0.0521FDA Survey 2002-03
CROAKER (Atlantic) Survey 1990-03
FLATFISH 20.050.04ND0.1822FDA Survey 1990-02
HADDOCK 0.030.04ND0.044FDA Survey 1990-02
HAKE0.01NDND0.059FDA Survey 1990-02
HERRING0.04NAND0.1438NMFS Report 1978
JACKSMELT0. Survey 1990-02
LOBSTER (Spiny)0.090.14ND0.279FDA Survey 1990-02
MACKEREL ATLANTIC (N. Atlantic)0.05NA0.020.1680NMFS Report 1978
MACKEREL CHUB (Pacific)0.09NA0.030.1930NMFS Report 1978
MULLET0.05NAND0.13191NMFS Report 1978
OYSTERS NDNDND0.2534FDA Survey 1990-02
PERCH OCEANNDNDND0.036FDA Survey 1990-02
PICKERELNDNDND0.064FDA Survey 1990-02
POLLOCK0.06NDND0.7837FDA Survey 1990-02
SALMON (Canned)NDNDNDND23FDA Survey 1990-02
SALMON (Fresh/Frozen)0.01NDND0.1934FDA Survey 1990-02
SARDINE0.020.01ND0.0422FDA Survey 2002-03
SCALLOPS0.05NAND0.2266NMFS Report 1978
SHAD (American)0.07NAND0.2259NMFS Report 1978
SHRIMPNDNDND0.0524FDA Survey 1990-02
SQUID0.07NAND0.40200NMFS Report 1978
TILAPIA 0.01NDND0.079FDA Survey 1990-02
TROUT (Freshwater)0.030.02ND0.1317FDA Survey 2002-03
TUNA (Canned, Light)0.120.08ND0.85131FDA Survey 1990-03
WHITEFISH0.070.05ND0.3125FDA Survey 1990-03
Mercury Levels of Other Fish and Shellfish
BASS (Saltwater) SURVEY 1990-03 
BLUEFISH0.310.300.140.6322FDA Survey 2002-03
BUFFALOFISH0. Survey 1990-02
CARP0. Survey 1990-02
CROAKER WHITE (Pacific) Survey 1990-03
GROUPER0.550.440.071.2122FDA Survey 2002-03
HALIBUT0.260.20ND1.5232FDA Survey 1990-02
LOBSTER (Northern/American)0.31NA0.051.3188NMFS Report 1978
MACKEREL SPANISH (Gulf of Mexico)0.45NA0.071.5666NMFS Report 1978
MACKEREL SPANISH (South Atlantic)0.18NA0.050.7343NMFS Report 1978
MARLIN0.490.390.100.9216FDA Survey 1990-02
MONKFISH0.18NA0.021.0281NMFS Report 1978
ORANGE ROUGHY0.540.560.300.8026FDA Survey 1990-03
PERCH (Freshwater)0.140.15ND0.315FDA Survey 1990-02
SABLEFISH0.22NAND0.70102NMFS Report 1978
SCORPIONFISH0.29NA0.021.3578NMFS Report 1978
SHEEPSHEAD0.13NA0.020.6359NMFS Report 1978
SKATE 0.14NA0.040.3656NMFS Report 1978
SNAPPER0.190.12ND1.3725FDA Survey 2002-03
TILEFISH (Atlantic) Survey 2002-03
TUNA (Canned, Albacore)0.350.34ND0.85179FDA Survey 1990-03
TUNA (Fresh/Frozen)0.380.30ND1.30131FDA Survey 1990-02
WEAKFISH (Sea Trout)0.250.16ND0.7427FDA Survey 1990-03

Based on table from FDA/Center for Food Safety & Applied Nutrition (


* Mercury was measured as Total Mercury and/or Methylmercury
ND - mercury concentration below the Level of Detection (LOD=0.01ppm)
NA - data not available
1 Includes: Sea bass/ Striped Bass/ Rockfish
2 Includes: Flounder, Plaice, Sole
3 Includes: Blue, King, Snow

Source of data

  • FDA Surveys 1990-2003
  • "National Marine Fisheries Service Survey of Trace Elements in the Fishery Resource" Report 1978
  • "The Occurrence of Mercury in the Fishery Resources of the Gulf of Mexico" Report 2000
  • Market share calculation based on 2001 National Marine Fisheries Service published landings data


Related Articles


  • Agency for Toxic Substances and Disease Registry (ATSDR). 1999. Toxicological profile for mercury. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
  • Cohen, Joshua T. Bellinger, D. Connor, W. Kris-Etherton P. Lawrence, R. Savitz, D. Shaywitz B. Teutsch S., and Gray G. A Quantitative Risk-Benefit Analysis of Changes in Population Fish Consumption. American Journal of Preventive Medicine. 2005. Volume 29 (4).
  • Environmental Protection Agency. EPA fact sheet. Mercury Update: Impact on Fish Advisories. June 2001.
  • TED Case Studies. Minamata Disaster. Accessed November 2005.
  • US Department of Health and Human Services and US Environmental Protection Agency. What you Need to Know about Mercury in Fish and Shellfish. March 2004.
  • Vermont Department of Environmental Conservation. Mercury Education Reduction Campaign. Accessed November 2005.

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