Ducie atoll will not be familiar to most readers of Our Planet, but perhaps it should be. In many ways this tiny uninhabited speck at the far end of a Pacific island chain symbolizes the challenges of trying to sustainably manage the world’s seas and oceans. A few years ago, scientists recording new species on nearby Pitcairn Island went to Ducie out of curiosity. In a morning’s stroll they catalogued almost 1,000 items of litter and rubbish — from old bread crates to plastic bags, a punctured football, discarded meat tins, and two toy cars. This unattractive haul collected almost 6,000 kilometres from the nearest continent is bad enough. But perhaps even more cause for alarm is the often-invisible pollution and sustained over-exploitation of marine resources. Some months ago, UNEP launched its flagship report — Global Environment Outlook-4. Its point of departure is the 1987 Brundtland Commission. GEO-4 asks how we have fared in the past two decades. The answer, including on marine issues, is ‘not very well’. In 1987 collapsed fisheries numbered 15 per cent globally. GEO-4 says this has now roughly doubled to 30 per cent. Twenty years ago, a fifth of fish stocks were over-exploited; this has now risen to about 40 per cent. In 2004, there were around 149 dead zone sites — often vast areas of seasonal, occasional or even permanent de-oxygenated water. New assessments put the total at 200.