I cover that here -
Tuna and Health"Many women eat tuna as part of their daily diet, but albacore tuna can have 3 times as much mercury in it as light tuna. Women paying more for the expensive albacore, thinking it is better, are actually increasing their mercury levels. The panel recommends only eating light tuna once a week, and wants the albacore tuna put on the 'caution' list along with other high mercury fish such as swordfish, shark, tilefish and king mackerel."