Blue Marine Foundation aims to restore the ocean to health by addressing overfishing, one of the world’s biggest environmental problems. Blue Marine is dedicated to creating marine reserves, restoring vital habitats and establishing models of sustainable fishing. BLUE’s mission is to see 30 per cent of the world’s ocean under effective protection by 2030 and the other 70 per cent managed in a responsible way.  The ocean has undergone devastating change over the last century. Marine life is under threat from climate change, deoxygenation, acidification, pollution, invasive species and plastic. But arguably the greatest of these threats is from overfishing. Industrial–scale, destructive fishing practices have laid waste to marine life and habitats, altered coastlines and forced small-scale fishing families to find work elsewhere. Above all, the ocean is critical to stabilising the planet’s climate, as detailed in the 2019 IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. The ocean produces more than half of the world’s oxygen and absorbs more than 90 per cent of excess heat within the climate system, thanks to the life within it. Overfishing is systematically undermining the ocean’s capacity to play this crucial role, not just through habitat destruction, but through the removal of pelagic marine life. Overfishing also represents a major food security issue, particularly for the three billion people who rely on both wild-caught and farmed seafood as their primary source of protein. We have to act now to protect our ocean if we are to stave off the worst effects of climate change and a global food crisis.