Project Update: August 2002

Dolphin from Prek Anchung, 40 km north of Phnom Penh.

Fieldwork began in May 2002, with boat and interview surveys throughout the upper Cambodia Mekong. Two continuous boat surveys (each of 7-8 days duration) were undertaken from Kratie to the Lao/Cambodian border - the most northerly extent of the dolphin's distribution in the dry season. A total of 785 km of survey effort over 67 hours were undertaken.Direct counts were used to estimate abundance, with a best estimate of 56 (range 47-73) dolphins sighted. These results were similar to those obtained during surveys in 2001 and indicate that the population is small and under severe threat of extirpation in the Mekong River.

In addition to boat surveys, a total of 45 hours were dedicated to photo-identification.Photo-identification during 2001 identified only two individuals. During 2002, more time was dedicated to photo-id and at least 20 individuals have been identified (with much of the data still to be analysed). This success is encouraging and will provide an effective method of studying minimum abundance, movements and association patters of the Mekong River Irrawaddy dolphin population.

A total of three Irrawaddy dolphins from the Cambodian Mekong River were recovered during 2002.Two of the three died as a direct result of accidental entanglement in gill-nets.By-catch in gill-nets is the most significant threat to the survival of the dolphins in the river.Additional threats include habitat degradation and pollution, vessel disturbance and harassment and potential dam and waterway constructions.

Preliminary surveys indicate that the population is small (perhaps numbering no more than 150 individuals), restricted in range and is in urgent need of biologically sound and socially acceptable conservation and protection measures.