Where did Mercury levels in fish originate?
Mercury that you get from fish is primarily in the form of methylmercury, which is produced by bacteria. While this is all naturally occurring, it is very likely that concentrations have increased due to industry, although I haven’t seen any sources detailing to what degree. While certain areas appear to have higher concentrations of mercury in fish, you can expect there to be some traces of methylmercury in pretty much all fish.
