Mercury in Fish

While there are many benefits of eating fish, if you are pregnant, planning on becoming pregnant or preparing meals for a young child, you need to be careful about the types of fish you eat. Some fish contain high levels of mercury which can be harmful to your developing baby and to young children. The developing baby is particularly vulnerable to high levels of mercury and high levels of exposure have been shown to affect brain development and nerve functioning.

Certain types of fish accumulate more mercury than others. This is due to a number of factors, including the age of the fish, natural environment, and food sources. Fish that are more likely to have higher levels of mercury are the larger, longer living or predatory species. Examples include:

• shark/flake
• billfish (including swordfish, broadbill and marlin)
• catfish, and
• orange roughy.

Recommendations for women planning pregnancy, during pregnancy and early childhood (up to 6 years of age)

The following fish should be eaten no more than once per fortnight (150g pregnant women, 75g children) with no other fish to be eaten in that fortnight:

• Shark (Flake)
• Broadbill
• Marlin
• Swordfish

The following fish should be eaten no more than once per week, (150g pregnant women, 75g children) with no other fish being eaten in that week:

• Orange Roughy (also sold as sea perch)
• Catfish

What about other types of fish?

Most other varieties of fish caught and sold in Australia contain low levels of mercury and can be eaten without concern. The National Heart Foundation recommends that fish be consumed at least twice a week for cardiovascular benefit, such as lowering blood cholesterol levels. The Australian Dietary Guidelines also advise eating one or two fish meals per week, and specify a serve of fish as being between 80 to 120 grams.

Fish is an excellent source of protein, is low in saturated fat and contains polyunsaturated fatty acids such as essential omega-3. It is also a good source of some vitamins, particularly vitamin D. Fish is also an excellent source of iodine providing from 20% to 30% of women's Recommended Daily Intake for one serve.


An Accredited Practising Dietitian can help you make changes to your diet and provide you with detailed information about the health benefits of fish and which species are safe to consume in pregnancy and childhood.