Meanwhile, general seafood guides provide the opportunity for immediate action on your part. But they won’t work if you just shop and shut up. A guide can even be counterproductive if it gives people the notion that they’ve accomplished something by simply not buying an overfished species when what they really need to do is become political activists. You need to wave seafood guides in the faces of store managers and restaurant personnel, urging them to boycott mismanaged species. Green fish buying is like green investing. If you do it silently, you’ve merely left a commodity to be purchased by someone who doesn’t worry about the planet. And those types are, alas, in the vast majority.