Fresh water fish pose a much bigger problem than saltwater fish. When it comes to salt water, what my son said was that the benefits of eating fish far outweigh the risks, although the highest level mercury fish- gulf tilefish, shark, the largest tunas, kingfish...should still be limited and pregnant women simply shouldn't eat them. They have recently noticed that the high levels of selenium in saltwater fish counteract the mercury. Which would explain the Seychelles study that showed loads of perfectly healthy kids, eating nothing but fish loaded with mercury. Their levels were high, but the kids were completely healthy. Interestingly, the studies of mercury consumption leading to damage was based on whale meat consumption in the Azores (or Faeroe) islands. Whale meat is much higher in mercury than fish, and doesn't have selenium. Freshwater fish live in much more confined bodies of water, with relatively higher toxin levels...and they don't accumulate selenium either. But mercury is the least of the problems in freshwater fish- dioxins, myrex, PCB's are all in the mix. An interesting study of snapping turtles and frogs on the Hudson river showed NO PCB contamination in the meat. Frogs are virtually fat free. Turtles have fat separate from the meat. Fat had sky high levels, but the meat had none!
