UN Secretary-General António Guterres has called for greater action to protect oceans. “The ocean is the foundation of life. It supplies the air we breathe and food we eat. It regulates our climate and weather. The ocean is our planet’s greatest reservoir of biodiversity,” he said in a message to mark World Oceans Day on Thursday. One example of how human activity is damaging the oceans, which make up more than 70% of the Earth's surface, is the fact that over a third of the world's fish stocks are being harvested at levels that are not sustainable. Also read: UN chief implicitly criticizes Cambodia's upcoming elections after top opposition party ban In addition to these advantages, the ocean generates resources that support societies, economic growth, and human health. Fish is the primary source of protein for over a billion people worldwide.“We should be the ocean’s best friend. But right now, humanity is its worst enemy,” he said, pointing to the evidence. The UN chief said human-induced climate change is heating the planet, disrupting weather patterns and ocean currents, and altering marine ecosystems and the species living there. Marine biodiversity is also under attack from overfishing, over-exploitation and ocean acidification, fish stocks are being depleted, and coastal waters have been polluted with chemicals, plastics and human wastes. Also read: Sudan military ruler seeks removal of UN envoy in letter to UN chief, who is 'shocked' by the demand “But this year’s World Oceans Day reminds us that the tides are changing,” he said. Guterres recalled that last December, countries adopted an ambitious global target to conserve and manage 30 per cent of land, and marine and coastal areas, by the end of the decade. The past year also saw a landmark agreement on fisheries subsidies, and the UN Ocean Conference in Lisbon, Portugal, where the world agreed to push for more positive action. Negotiations for a global, legally binding treaty to end plastic pollutions are currently underway, and in March, countries agreed the historic High Seas Treaty on the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction. “Realizing the great promise of these initiatives requires collective commitment,” Guterres said.“This World Oceans Day let’s keep pushing for action. Today and every day, let’s put the ocean first.”