Death of the last known river dolphin in the transboundary pool in the Mekong between Laos and Cambodia

The Mekong dolphin population has long been IUCN red-listed as Critically Endangered.

The last known river dolphin in the transboundary pool on the Cambodia-Laos border was found dead on February 15, 2022. This death most likely represents a national-level extinction for Laos. The dolphin was 25 years old, male, 260cm in length and weighed 110kg (243 pounds).

The population was publicly declared functionally extinct in 2016 when only three dolphins were left. There are an estimated 89 river dolphins still present in the 180km (112 miles) long stretch of the Cambodia part of the Mekong river according to surveys conducted in 2020.

The Mekong dolphins have faced mounting threats for decades. Major known causes of the decline of the transboundary population have included drowning in gill-nets, disruptions to river flow from upstream dams, overfishing, and use of damaging fishing practices such as electrofishing.

In 2020 and the first half of 2021, river patrols covering the dolphins’ habitat, in Kratie and Stung Treng provinces, removed nearly 112km (70 miles) of illegal gill-nets and more than 131km (81 miles) of illegal hook long lines. Patrols also stopped 20 cases of electrofishing.

Dam operations along the Mekong have had serious impacts along the river’s length. The planned construction of dams on the Mekong mainstream further threatens the survival of the remaining dolphins and other aquatic megafauna.

“The Mekong dolphins are regarded as sacred animals by Cambodian people.