The Irrawaddy river dolphin (Orcaella brevirostris), the Asian dolphin lives in coastal waters, brackish estuaries and freshwater rivers in Southeast Asia and north Australia. It is one of the four river dolphins live in freshwater. This endangered dolphin is pale gray and adult is at the lengths of 2-2.75 meters. With a round head and no beak and is occasionally mistaken for a beluga whale or a porpoise.

According to WWF, the Irrawaddy dolphin has received very little attention, but is probably in very serious danger of disappearing over much of its range. Because its distribution is in coastal areas, the Irrawaddy dolphin is often vulnerable to the harmful effects of human activities. Irrawaddy dolphins feed on a variety of fish, crustaceans and cephalopods. Little is known about their reproduction.

WWF Cambodia conducted “Report Abundance of Mekong River Dolphin Population” during April and May in 2007. With totally 139 hours 32 minutes searching effort, the research team observed a total of 61 dolphins. And the preliminary population abundance estimate for the Mekong dolphin was between 66 and 86 dolphins, with a best estimate of 71 dolphins by MARK statistical program, using a closed population model at the end of May 2007.