A dolphin long thought to be extinct was caught by a fisherman in Vietnam last week.

On May 15, Phan Van Thai, 49, was fishing with his wife on the Co Chien River in Cho Lach, Ben Tre, when they discovered a creature trapped in their net, VN Express reported. They were unable to identify it at first.

Phan stored the dead animal in ice and waited for authorities, who identified it as an Irrawaddy dolphin, previously thought to have vanished from the Mekong River in Vietnam.

Vu Long, the director of the Center for Biodiversity Conservation and Endangered Species, said no dolphins had been recorded there in the past 30 years. He pointed out that the discovery was important and ground-breaking and that research projects were necessary.

The dolphin, an old female, had lost all her teeth.

Samples of its DNA were taken and sent to the Directorate of Fisheries and the Department for Nature Conservation and Biodiversity. The Irrawaddy dolphin – also known as the Orcaella brevirostris – is a euryhaline species of dolphin that mostly lives near coasts and river mouths.

It is also found in nearby Cambodia, in the Mekong River. It is a protected animal under the Convention on International Trade in Endangered Species of Wild Fauna and Flora.