One-fifth of fish species in the Mekong river face the threat of extinction, according to a new report from a coalition of regional and international environmental groups. The Mekong — among the world’s most biodiverse rivers, surpassed only by the Amazon and the Congo — is home to some 1,148 recognised species of fish, with millions of people relying on its waters for their incomes. But it faces a multitude of threats, according to environmentalists, […]