Based on a study of 5,829 populations of 1,234 mammal, bird, reptile, and fish species in the world's oceans, the WWF found a decline of 49 percent between 1970 and 2012. Fish were the most threatened, in large part because of human overfishing: Over a third of fish consumed by humans measured by the Living Planet Index are under threat of extinction, with one family of tuna and mackerel falling 74 percent between 1970 and 2010. Read More?at www.news.vice.com