Why study marine mammals in Cambodia?
Marine mammals are top predators, keystone species and can be used as indicators of ecosystem health. In order to effectively focus conservation efforts and ensure these populations thrive, we must collect vital baseline data and continuous monitoring schemes.
Cambodia is home to 11 marine mammal species (Beasley and Davidson, 2007) and whilst confirmed species are protected by fisheries law (MAFF, 2007), this law is not informed with sufficient data to implement successful marine mammal conservation strategies. Through the creation of The Cambodian Marine Mammal Conservation Project, this much needed data will be collected and used towards creating tailored marine mammal conservation legislation.
For an ecosystem to be healthy and productive, it should be in balance with each species playing its part. For this reason, supporting the health of marine mammal populations, supports the health and productivity of the ecosystem.
What marine mammals are present in the Kep Archipelago?
Whilst eleven marine mammals have confirmed presence in Cambodia's seas (Beasley and Davidson, 2007), only one marine mammal has been seen in our study area (the Kep Archipelago), the Irrawaddy dolphin (Orcaella brevirostris).
Irrawaddy dolphins are a marine and freshwater species distributed in rivers, lakes, estuaries and coastal water throughout Southeast Asia. They are considered 'Endangered' on the IUCN's list of threatened species (IUCN, 2017), primarily due to their declining an fragmented populations.
The Irrawaddy dolphin is robust (2.3 to 2.7m) with a round melon, no beak, and a mouth line that angles up, giving it a smiling appearance. It has a long flexible neck, allowing it to turn its head from side to side, a distinct neck crease, and a small triangular dorsal fin with a blunt tip. The pectoral fins are large and spatulate, with curved leading edges and rounded tips. The Irrawaddy dolphin has a uniform dark blue-grey to medium grey or pale blue colouration, with a paler underside. In the field, it is most likely to be confused with the finless porpoise but the porpoise is much smaller and lacks a dorsal fin.
Irrawaddy dolphins are shy of boats, not known to bow-ride, and generally dive when alarmed. They are relatively slow moving but can sometimes be seen spyhopping and rolling to one side while waving a flipper, and occasionally breaching. They have been seen spitting water from their mouths in the wild, and this behaviour is thought to help them hunt by confusing schools of fish. They are generally found in groups of 2-3 animals, though sometimes as many as 25 individuals have been known to congregate in deep pools.
Whilst no other marine mammals have been seen in the Kep Archipelago, interview surveys undertaken in 2002 and 2004 in the region suggest that the region was once a dugong (Dugong dugon) hotspot (Hines et al., 2008). The same interviews reveal that dugongs are still seen today at local markets in the Kampot and Kep regions.
Beasley, I. and Davidson, P. (2007). Conservation status of marine mammals in Cambodian waters, including seven new cetacean records of occurrence. Aquatic Mammals, 33(3), pp 368-379.
Hines, E., Adulyanukosol, K., Somany, P., Ath, L., Cox, N., Boonyanate, P. and Hoa, N. (2008). Conservation needs of the dugong Dugong dugon in Cambodia and Phu Quoc Island, Vietnam. Oryx, 42(01).
IUCN (2017). Orcaella brevirostris (Irrawaddy Dolphin). [online] Available at: http://www.iucnredlist.org/details/15419/0 [Accessed 18 Dec. 2017].
Ministry of Agriculture, Forestry and Fisheries; Fisheries Administration, Kingdom of Cambodia (2007). Law on Fisheries.
Tubbs, S.E., Akkaya, A., Cote, G., Jones, A.L. and Notman, G.M. (2019). Sighting and stranding reports of Irrawaddy dolphins (Orcaella brevirostris) and Dugong (Dugong dugon) in Kep and Kampot, Cambodia. Aquatic Mammals, 45.5, pp.563-568.
Tubbs, S.E., Keen, E., Jones, A.L. and Thap, R. (2020). On the distribution, behaviour and seasonal variation of Irrawaddy dolphins (Orcaella brevirostris) in the Kep archipelago, Cambodia. The Raffles Bulletin of Zoology, 68, pp.137-149.