Have you checked your mercury levels recently? 
Dm - LOL!

But, actually that is certainly an important concern, esp. for pregnant ladies & children; since we eat a lot of seafood, I do keep a watch on the mercury levels in fish - shellfish, one of our favs is fine (although one might catch other 'things' eating the stuff raw, as we do!); for sushi, just eat that a couple times a month (usually stick to tuna, salmon, & yellowtail) - it's mainly those fish that are 'high' on the food chain, and my main concern is
swordfish, a favorite, so order it only 3-4 times a year - for those interested (as you should be if seafood is a BIG part of your diet), take a look at the
US FDA Tables -
