Mercury is a heavy metal that enters oceans and seas from natural and industrial sources (such as pollution). Bacteria convert it into methylmercury, the most toxic form. When small fish consume contaminated plankton, and larger fish eat them, mercury accumulates in their bodies over time. The larger and older the fish, the higher the mercury levels.
Top Fish High in Mercury:
Shark 🦈
Sharks live long and feed on other fish, making them extremely high in mercury.
Regular consumption can lead to neurological issues and mercury poisoning.
Swordfish
A large predator fish known for having very high mercury levels.
Pregnant women and children are advised to avoid it.
Bigeye & Yellowfin Tuna
While canned light tuna has lower mercury, bigeye tuna and yellowfin tuna contain high levels.
King Mackerel
One of the most mercury-contaminated fish, making it unsafe for frequent consumption.
Tilefish
Commonly found in the Gulf of Mexico and among the highest in mercury contamination.
Health Risks of High-Mercury Fish:
Nervous system damage, especially in fetuses and children.
Kidney and liver problems due to mercury buildup.
Memory and concentration issues in adults.
Digestive and immune system disorders.
Healthier Alternatives:
Luckily, some fish are rich in omega-3 and protein but low in mercury, such as:
Salmon
Sardines
Anchovies
Tilapia
Cod
Tips for Buying Fish:
✅ Choose smaller fish instead of large ones, as they contain less mercury.
✅ Avoid high-mercury fish during pregnancy.
✅ Do not eat high-mercury fish more than once a month.
✅ When in doubt, follow recommendations from FDA and EPA.