Second, water pollution which come from chemicals of agriculture activity. Third, overfishing which has affected with marine ecosystem. Fourth dredging for building port that mark the sediment cover the coral reef. Finally, coral bleaching and invading of crown of thorns starfish that are the most changer for coral reef .So Australia’s government is going to find the way to protect, improve and development in order to the Great Barrier Reef don’t risk extinct that WWF and Greenpeace is considering about this .