Irrawaddy dolphins -- small, shy creatures with domed foreheads and short beaks -- once swam through much of the mighty Mekong, all the way to the delta in Vietnam.

But their population in the river has dwindled from 200, when the first census was taken in 1997, to just 89 in 2020, largely due to illegal fishing, habitat loss and plastic waste.

"Currently, we have some 105 dolphins," Agriculture Minister Dith Tina said during a ceremony to mark National Fisheries Day.

In the first six months of this year, eight new dolphin calves were recorded, but there were also two deaths, the agricultural ministry said.

The boost to numbers follows the birth of eight dolphins last year, a ministry statement said, while 2023 also saw five deaths recorded.

"The ministry has strongly taken measures against fishing offences and the making and distributing of destructive fishing tools that seriously damage marine resources," Dith Tina said.

Last year Cambodia's then leader Hun Sen U-turned on a law to protect the species, saying "dolphins keep dying" while the fishing industry suffered from the conservation legislation.

Irrawaddy dolphins feature on the "Red List" of endangered wildlife by the International Union for Conservation of Nature (IUCN).

Adding to concerns about their survival, around 70 percent of the population is now too old to breed.

The dolphins' habitat has also been reduced by upstream dams in Laos and China and climate change, which have had a major impact on water levels in the river.