Eastern Gulf of Thailand Drainages




J. Hales



Major Habitat Type

Tropical and subtropical coastal rivers

Drainages flowing into

Gulf of Thailand

Main rivers to other water bodies

Chanthaburi River, Welu River, Trat River, Meteuk River



Straddling the border between southeastern Thailand and western Cambodia (with a small extension into Vietnam), this ecoregion comprises the small coastal rivers draining to the Gulf of Thailand between the Chao Phraya and Mekong basins.

Terrestrial habitats

The ecoregion largely comprises Cardamom Mountains rain forests, with Chao Phraya lowland moist deciduous forests in the north and pockets of Indochina mangroves along the coast (Wikramanayake et al. 2002).

Description of endemic fishes

This ecoregion may contain a few possible endemics (M. Kottelat pers. comm. 2006).

Justification for delineation

For Southeast Asia, delineations were determined using a bottom-up approach that employed both published and unpublished field data and expert assessment (Abell et al. 2008; Kottelat 1989). This ecoregion has a fauna with many similarities (although species-poorer) with the Mekong Delta ecoregion [729]. It may contain a few endemics, although endemicity might be a sampling artifact caused by insufficient collecting in both ecoregions. The fauna also has some affinities with the Malay Peninsula Eastern Slope ecoregion [734]. The break between ecoregions 734 and 731 might be real or due to insufficient sampling and/or extinction in the heavily impacted coastal area of Mae Khlong [733] and Chao Phraya [732] (M. Kottelat pers. comm. 2006). This ecoregion includes some peat swamps, apparently extirpated in Thailand and unexplored in Cambodia and Vietnam (Vidthayanon 2002).


  • Abell, Robin,M.L. Thieme,C. Revenga,M. Bryer,M. Kottelat,N. Bogutskaya,B. Coad,N. Mandrak,S.C. Balderas,W. Bussing,M.L.J. Stiassny,P. Skelton,G.R. Allen,P. Unmack,A. Naseka,R. Ng,N. Sindorf,J. Robertson,E. Armijo,J.V. Higgins,T.J. Heibel,E. Wikramanayake, (2008). "Freshwater Ecoregions of the World: A New Map of Biogeographic Units for Freshwater Biodiversity Conservation" BioScience 58 (5) pp. 403-414.
  • Kottelat, M. (1989). "Zoogeography of the fishes from Indochinese inland waters with an annotated check-list" Bulletin Zoologisch Museum Universiteit van Amsterdam 12 (1) pp. 1-54.
  • Wikramanayake, Eric,Dinerstein, Eric,Loucks, C.,Olson, D.M.,Morrison, J.,Lamoreux, J. L.,McKnight, M.;Hedao, P. (2002). "Terrestrial ecoregions of the Indo-Pacific: A conservation assessment" Washington, DC: Island Press.
  • Vidthayanon, C. (2002). "Peat swamp fishes of Thailand" Bangkok, Thailand: Office of Environmental Policy and Planning.