The first two-thirds or so of the book provide first a history of the seas and of humans fishing them, and then a rather scary description of all the ways we're destroying them. Of particular note is the way that different factors combine to produce worse outcomes than any single factor would; for example, dead zones are a function not only of agricultural run-off, but also upstream damming, ocean warming, and over-fishing. Even in this first part of the book, however, the author's inclination towards moderate 'solutions' is apparent, and the last third of the book is where things really come apart. Not only did the search for solutions seem a bit all over the place, compared with the well-structured description of the challenges the oceans face, but the proposed fixes seemed to me to be too half-hearted to make a real difference. At one point the author says "The solution is not for a handful of people to stop eating fish" which, while true, seems like a straw man. Commercial fishing is so destructive (and I learned lots through reading this book that I hadn't even realized before) that attempting to patch around it seems doomed to failure. Tl;dr: read it for the rather gloomy elucidation of the trajectory of the oceans, but prepare to be frustrated by the proposed solutions.