A school of about 20 Irrawaddy dolphins has been sighted around the Ba Lua Archipelago in the protected Kien Giang Biosphere Reserve, the southern province of Kien Giang.

The population was discovered by a group of six researchers from the Centre for Biodiversity and Development run by the Institute of Tropical Biology and HCM City University of Natural Sciences.

Vu Long, one of the researchers, said the number of dolphins sighted was larger than schools in the Malampaya Channel in the Philippines and the Mekong River, where populations of between seven and 10 were sighted.

Little research on the Irrawaddy dolphin has been conducted in Vietnam and they are not listed in the country's Red Book of endangered species, Long said.

On Jan.12, the researchers will travel to Thailand to work with the International Union for Conservation of Nature (IUCN) to work out a detailed plant to protect the dolphins, he said.

In the meantime, researchers have joined hands with local fishermen to track the population of dolphins in the Ba Lua Archipelago.

Five populations of Irrawaddy dolphin, whose scientific name is Orcaella brevirotis, were thought to be living in Vietnamese waters.

The IUCN lists the dolphin in its Red book of vulnerable species. /.