KATHARINE HOURELD and DUNCAN MIRIRI THE Japanese ship that ran aground on a reef off Mauritius two weeks ago has now stopped leaking oil into the Indian Ocean but the island nation must still prepare for "a worst case scenario", Prime Minister Pravind Jugnauth said late on Monday. Conservationists said they were starting to find dead fish as well as seabirds covered in oil, increasing fears of an ecological catastrophe despite a massive local cleanup operation that includes making floating booms from leaves and human hair. Jugnauth said the leak from a damaged oil tank on board the stricken vessel,…