Bolivia says Amazon pink dolphins, the country's only freshwater mammal species, will be protected under a new law. The legislation, signed by Bolivian President Evo Morales, bans fishing for pink dolphins, known in the country as bufeo, and accords the species the status of a national treasure, the BBC reported Tuesday. In a ceremony held on the shores of the Ibare River, Morales said the armed forces would be utilized to protect the mammals' freshwater habitat, which is under threat from erosion, pollution and logging along the Amazon River. The single greatest threat to the dolphins is contamination of rivers in the region by mercury, used in illegal gold mining operations, conservationists said. Male Bolivian freshwater pink dolphins can weigh up to 440 pounds, and the species -- Inia bolivienses -- is similar to dolphins living in neighboring Brazil, Peru, Colombia and Venezuela.