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PHNOM PENH, Aug. 17 (Xinhua) -- The critically endangered Irrawaddy dolphin population in the Mekong River numbers just 85, World Wildlife Fund (WWF) new research revealed on Wednesday.
Calf survival was found to be very low, leading researchers to conclude that the small population is declining and at high risk of extinction, said the Fund's statement sent to Xinhua News Agency on Wednesday.
According to Li Lifeng, Director of WWF's Freshwater Program, the research is based on photographic identification of dolphins through individually unique features of their dorsal fins. "Most of the dolphins can be identified, and we use that information to estimate the population size," he said.
Although this population estimate is slightly higher than the previous estimate, the researchers were quick to note that the population had not increased over the last few years.
"With a larger dataset and recent analytical advances, previously unidentifiable dolphins which had few marks on their dorsal fins have been included," he added.
However, surveys conducted from 2007 to 2010 show the population slowly declining.
"Evidence is strong that very few young animals survive to adulthood, as older dolphins die off and are not replaced," he explained.
"Pressures of gill net entanglement and high calf mortality we are really worried for the future of dolphins," Li said.
However, Touch Seang Tana, chairman of Cambodia's Commission for Conversation and Development of the Mekong River Dolphins Eco- tourism Zone, rejected the WWF's finding, saying that last year, 4 dolphins were killed by fishing nets, but up to 7 newborn dolphin babies were found.
He estimated that the total population of Mekong dolphins in the north-eastern provinces of Kratie and Stung Treng is between 155 and 177 now, up from just 100 in 2006.
The Mekong River Irrawaddy dolphin has been listed as critically endangered on the World Conservation Union Red List of Threatened Species since 2004.