The population of the Sumatran tigers (Phantera Tigris Sumatrae) in the forests of Sumatra has decreased to over 500 due to hunting and opening of plantations, local media reported in Jakata Friday.

Head of the Gunung Lauser National Park, Area I in Sumatra Island, who goes with single name, Rusman said that opening of new plantations for palm oil narrowed the species area for hunting preys.

"There are now only 500 left of them, and their number is constantly declining," Rusman was quoted by Antara news agency as saying.

"The opening of plantations is still posing a serious threat to the Sumatra tigers," he said.

He said South Aceh regency is one of the areas in Gunung Leuser which is most prone to disturbances by the tigers and other wild animals, like elephants and bears.