I'm currently reading WHAT TO EAT by Marion Nestle. She's basically the leading nutritionist in America, and this book is her opus--a guide to what to put in your belly. The Seafood chapter has been one of the most shocking chapters for me. I don't eat fish or seafood--never liked the taste. I always felt like I was missing out, since most of my friends and family enjoy it, and because it seems to have a lot of health benefits with the whole omega-3 thing and all that jazz. But what I didn't fully realize is how contaminated (with methylmercury, etc) and environmentally unsound (farming fish and seafood really pollutes the water) fish can be. Yes, there are some very healthy options, but most of the foods people really like, such as tuna, salmon, and shrimp, are some of the worst offenders. It's definitely made me glad that I get my omega 3s from veggies and flax.
But I am glad to see that some retailers are cleaning up their act. There's a piece in today's NYT about Wegman's insisting on environmental and safety standards for their shrimp. Hopefully they're the first of many...