By Roberta Attanasio Salmon farming—the fastest growing food production system in the world—is going through hard times in Chile, the world’s second-largest salmon producer after Norway. Last year, Chile exported $4.5 billion of farmed salmon, but now a deadly algal bloom is killing millions of farmed fish. A few months ago, an estimated 40,000 tons of salmon died in the Los Lagos region, which is known as the Switzerland of the Southern Hemisphere’s—the snow-capped peaks of the Andes Mountains tower over deep mountain lakes and green farming valleys, creating a fairy-tale landscape. Unlike Switzerland, the fairy-tale landscape extends down to the coast and its beaches, which became covered with dead…