Montreal-based food writer Taras Grescoe thinks something fishy is up with the global seafood economy. From pollutants to piracy, preservatives to Patagonian toothfish, Grescoe surveys the state of our collective waterways in his new book Bottomfeeder: How to Eat Ethically in a World of Vanishing Seafood, which combines some literal seabed muckraking with a fascinating travelogue. Each chapter follows a specific fish down the food chain from net to dinner plate; the book is a......