The number of porpoises washed ashore has increased enormously in recent decades. Where fewer than a hundred dead porpoises were reported each year in the 20th century, this number increased steadily. Peak stranding years were 2011 and 2013 when almost 900 stranded dead porpoises were found every year on the Dutch coast alone!

Source: http://www.windaction.org/posts/50493-question-of-the-month-why-more-often-dead-porpoises-around-offshore-wind-farms?fbclid=IwAR3ZdDpf_PRWcVC7zpptOx2Ab7jfuq5IRaWZDXoqQbPfSwgbCXuVBBhefJE#.XbsRs_nPxqN