Vessels may take too many fish ­– overfishing – which is causing our fisheries to collapse. Then there is the problem of illegal fishing, which can occur in protected areas, in another country’s waters or on the high seas. Many countries simply don’t have the capacity to enforce fishery management rules. As a result, illegal fishing has become a multi-billion-dollar industry, worth up to $23bn each year. Because of overfishing – both legal and illegal – one third of fisheries assessed in a study by the UN Food and Agriculture Organisation were overfished and over half were fully fished. This threatens jobs and food security for millions of people, all around the world.