Two of the nine baby dolphins born in 2007 died - one in January and another last week, said Touch Seang Tana, head of the governmental Commission of Mekong Dolphin Conservation.
In 2006, 14 babies were born, six of which died, he said, adding that these numbers were encouraging given the fact that the previous years saw an average of 15 babies die.
"Before there were a lot of deaths. Now there is only two," he was quoted by English-Khmer language newspaper the Cambodian Dailyas saying.
The improvements are attributed to education campaigns over the last couple of years warning villagers not to use gill nets and encouraging them to find work in tourism instead of fishing.
However, the surviving baby dolphins are underweight and look unhealthy, he said, adding that the baby dolphin dying in January weighed only 3.8 kg and the baby found last week tangled in a fishing net 4 kg, some one kg shy of the normal weight.
"The remaining babies are small," he said, adding that the baby dolphin’s failing health is partly due to a shortage in the fish their mothers eat, which is something he attributed to global warming and shifting temperatures.
World Wildlife Fund' Cambodia Country Director Teak Seng said that global warming may be a threat to the dolphins, but there is no conclusive evidence to support the theory.
"We don't have any scientific evidence that supports this casual relationship, therefore further research needs to be conducted," he said.
"While dolphins are very sensitive to changes in their environment, such as water temperature and quality, other factors may be more influential such as diseases and water pollution," he added.
According to the Commission of Mekong Dolphin Conservation, there are currently 140 to 150 dolphins in Cambodia, over some 90 in 2006.
The Cambodian government has adopted a series of measures to protect the animal, such as no use of fishing net in its inhabiting area, and encouragement of local people to salvage those struggling in nets.