Journalist Paul Greenberg’s 2010 nonfiction work Four Fish: The Future of the Last Wild Food explores the global commercial fishing market and aquaculture, specifically regarding the consumption of tuna, cod, sea bass, and salmon. The central argument of this book is that people must manage our shared oceans so that fish can sustainably exist in farm settings and in the wild. Regarding salmon, for example, Greenberg shows how farming irresponsibly threatens wild salmon populations and argues that the seafood market has chosen the wrong fish to try to domesticate. This book includes accounts from all over the globe. Greenberg’s extensive research demonstrates how industrialized fishing has decimated wild populations of fish. The introductory chapter of this text concludes by saying that, through the story of these four fish, Greenberg will contrast “human wants” and “global needs.” However, he will also provide a solution for “equitable and long-lasting peace between man and fish.” The answer this work points to requires international political action and responsible ocean management.

Four Fish begins with a graphic description of AquaBounty's plan to modify salmon genetically in order to make them bigger and more suitable for human consumption. To produce the salmon, a chinook was crossed with an ocean "pout." The company claims the fish would be sterile, but environmentalists (and many others, including salmon farmers) cried foul.

Later, Greenberg talks extensively about the problems in salmon farming. The first problem is that it often takes three pounds of other wild fish, used for feed, to get one salmon ready for production. The next main problem is salmon are farmed in "sea cages" often submerged near a different type of salmon. Not only can the salmon introduce parasites and diseases, but they can escape, negatively affecting the ecosystem. 

Greenberg wants to figure out ways to deal with these issues and uses his book to do so. He looks into the recycling of fish feces, the reduction of pollution, the use of better cages, and better control of growing conditions. Probably the newest idea suggested is the integration of salmon with other sea creatures in order to create an appropriate environment. 

In conclusion, Greenberg also proposed different feed and even using a completely different fish for human consumption altogether: the little-known arctic char. As Greenberg says:

Arctic char strike me as a good environmental compromise and to my palate, they’re pretty tasty.