More than one billion people depend on the ocean for their primary source of food, with 260 million employed by global marine fisheries alone. About 80% of all traded goods are shipped over the ocean and nearly 30% of the world’s oil is produced in offshore fields and distributed worldwide. In addition to these established uses of the ocean, increases in offshore renewable energy, aquaculture and mining are rapidly emerging. All of this industrial machinery powers a 1.5–2.5 trillion dollar ‘blue economy’ that is growing faster than the overall global economy but is also causing rapid environmental decline. A third of fish stocks are operated beyond biologically sustainable levels and an estimated 30–50% of critical marine habitats have been lost owing to human industrialization.