Gulf of California, The World's Aquarium

"The [Gulf of California] has an almost legendary status among divers and marine naturalists. John Steinbeck wrote a book about his voyage here aboard a scientific collecting expedition in 1940, and Jacques Cousteau famously called it “the world’s aquarium” . . . The 60,000-square-mile gulf is divided between a temperate zone (north of La Paz, the state capital of Baja California Sur) and a warm-water “Panamic” zone . . . The confrontation and subtle mixing of these two ecosystems partly accounts for its richness: some 900 fish species and 32 types of marine mammal gather to feed and breed here . . . Decades of overfishing have unbalanced the ecosystem, taking top predators such as sharks and marlin out of the food chain and leading to a surge in other species."