Paul Greenberg's Four Fish: The Future of the Last Wild Food should be required reading for anyone who eats seafood. The assignment won't be a burden. Greenberg is an unfailingly entertaining writer, and his book arms you with the information you need to make intelligent choices when you are confronted by the confusing and sometimes contradictory offerings at the fish counter.
Greenberg tells his story through what he calls four "archetypes of fish flesh": salmon, sea bass, cod, and tuna. These are species that humans are attempting to "master in one way or another," either by managing wild populations or by domesticating them and raising them as we do hogs, poultry, sheep, and cattle.
An avid angler, Greenberg takes fish conservation personally. The book starts with a story about all the largemouth bass dying in his favorite boyhood fishing hole in Connecticut—a microcosm of what's happening in all of the world's oceans today to the fish species people happen to like to eat. The four fish he has chosen to focus on mark distinct steps in the grim worldwide decline and human attempts to ameliorate it.
Salmon are tough, lightening fast, capable of migrating thousands of miles over oceans and up seething rivers, but they cannot tolerate the encroachment of civilization. When people come with their farm fields, dams, and mills, salmon begin to disappear. So we've tried to tame them and raise them in pens—never mind that it would be hard to pick a species whose natural traits make it less suitable for domestication.