I've just read a book by Paul Greenberg called "American Catch: the Fight for our Local Seafood." This book explains why about 90% of the fish and seafood Americans eat is from foreign sources, mainly Asia and India. Because of our environmental laws, we have the cleanest and healthiest fish/seafood in the world. We export most of it. We import the farmed products grown in filth and fed anything available to enhance quick growth, bathed in antibiotics because of parasites and disease. These are sold at a low price which substantially undercuts that of American fisherman.
An easy to read 250 page book, Greenberg writes about history, politics, environmental policy and marine biology. The frightening part is how blatantly unhealthy most of the imports are and how these foreign coastlines are left void of life because of the way the farmed fish are raised. the book sure gives you pause every time you are tempted to buy that cheap fish and seafood at you local market.