safety mechanism: The International Maritime Organisation (IMO), the world's apex body responsible for the safety and security of shipping, has adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments to prevent the spread of invasive aquatic organisms. The decision was taken during a meeting in London from February 9-13. But the treaty will come into force only a year after 30 countries, representing 35 per cent of the world's shipping tonnage, have ratified it. Invasive aquatic species that travel to new environments by ships' ballast water or other carriers are one of the four greatest threats to the world's oceans (see: [2]