4 Things to Know About Mercury in Tuna

Bigger tuna have more mercury Mercury builds up in tuna over time, so older, larger fish contain higher levels. Species like bluefin and bigeye are riskier than smaller ones like skipjack.

Skipjack is the safest choice Skipjack, the small tuna used in most “light” canned tuna, has the lowest mercury levels. It is safe to eat a few times a week.

Albacore is moderate, bluefin and bigeye are high risk Albacore (“white” canned) is a bigger species with moderate mercury—limit to once a week. Bluefin and bigeye, often used in sushi, can have high enough mercury to require caution.

Size matters within a species A 200-pound bluefin has more mercury than a 100-pounder. For regular consumption, stick with skipjack; save larger, pricier tuna for occasional treats.