Patna, Dec 2 (IANS): A Gangetic dolphin, an endangered species, was killed by suspected poachers in a Bihar dolphin sanctuary, officials said Tuesday.

"A Gangetic dolphin was found dead near Raghopur Bahtara in the Vikramshila Gangetic Dolphin Sanctuary in Bhagalpur district late Monday," district forest official Vidyapati Sinha said.

Sinha said the dolphin was 5.5 feet in length and its weight was nearly 60 kg.

"We are probing the cause of death and are waiting for the postmortem report," he said.

Over a decade ago, a dolphin sanctuary was set up along the Ganges at Kahalgaon near Bhagalpur. This is Asia's only fresh water dolphin sanctuary, spread over an area of 50 km.

But dolphins are often targets of fishing near the sanctuary areas. They are killed for their skin and oil and also because of the high demand for their meat and fat, say experts.

"A dead pregnant dolphin was once found near the area," Sunil Choudhary, an expert on dolphins, said.

Choudhary, who is the coordinator of Vikramshila Education and Bio-Diversity Research Centre, said the dead dolphin was probably trapped in a fishing net.

Despite a 2011 Patna High Court order that asked the state government to check poaching, dolphins are still being killed.

In 1996, freshwater dolphins - locally known as "sons of the river" - were categorised as an endangered species.

Experts estimate that currently these dolphins number between 2000-2500. According to the World Wide Fund for Nature, in the 1980s the dolphins numbered around 3500 in the Ganges delta alone.