WWF's Living Planet Report, released every two years, is a leading science-based analysis on the health of our planet and the impact of human activity upon it. The Living Planet Report 2014 detailed alarming declines in biodiversity, showing species populations falling by half between 1970 and 2010. It also showed that humanity, particularly in developed nations, continues to make unsustainable demands on nature. This special edition takes a deeper look into these findings, and their implications, for the marine realm. Data on marine ecosystems and human impacts upon them is limited, reflecting the lack of attention the ocean has received to date. Nevertheless, the trends shown here present a compelling case for action to restore our ocean to health.