Livewell

Contaminant

Mercury

A heavy metal that builds up as methylmercury in fish.

What it is

Bacteria in water convert mercury into methylmercury, which fish absorb faster than they can shed it. It concentrates up the food chain, so older and larger predatory fish (walleye, pike, bass) carry the most. In people it can harm the developing brain and nervous system, which is why pregnant women and children face the strictest limits.

Cleaning and cooking will not help

Trimming, skinning, and cooking won't lower it — it's stored in the muscle. Reduce exposure by eating smaller, younger fish and fewer meals.

How to prepare it

  • Trimming and skinning won't help — this settles in the muscle you eat, not the fat.
  • Cooking doesn't remove it either; a fillet carries the same amount cooked or raw.
  • Eat smaller, younger fish — they carry less.
  • Follow the meal limits above and space your meals out across the month.

Waters with Mercury advisories

2,619 waters across 40 states, showing the first 200.