This is a useless advice as there is no accountability/testing for these claims.... you cannot even be sure what kind of fish that you are buying nowadays (organic is even harder to prove). DNA testing would solve that, but the FDA apparently don't have the budget. For example: https://www.nydailynews.com/life-style/health/one-third-fish... .
That's where the "research" bit comes in. Take that report to your fish-monger[1] and ask him about it. If he has a strong opinion about it he's probably a keeper. If not, ditch him and get your fish from somewhere else. Again, check online vendors.
