There is a great book by a marine biologist that goes into detail about these topics. It's called The Ocean of Life - The Fate of Man and the Sea by Callum Roberts. It was recommended to me here on HN several years ago, and I think that recommendation bears repeating. He goes into great detail about conservation topics for half the book, and the other half has to do with climate change and its effects on the oceans (and how that affects humanity).