Northeastern Borneo




J. Hales



Major Habitat Type

Tropical and subtropical coastal rivers

Drainages flowing into

South China Sea, Sulu Sea, Celebes Sea

Main rivers to other water bodies

Some of the larger rivers include the Padas, Sugut, Labuk, Kinabatangan, Segama, Sebuku, Sembakung, and Sesayap.



This ecoregion includes Sabah (Malaysia) and the Sebuku, Sembakung and Sesayap basins in North Kalimantan (Indonesia).

Terrestrial habitats

Terrestrial ecoregions include Borneo montane rain forests [IM0103], Borneo lowland rain forests [IM0102], Kinabalu montane alpine meadows [IM1001], Borneo peat swamp forests [IM0104], Sundaland heath forests [IM0161], and Sunda Shelf mangroves [IM1405].

Description of endemic fishes

The ecoregion contains 40 endemics, which represent more than 25% of the species. Fifteen of these are cyprinids, followed by Osphronemidae with five species, and Bagridae, Balitoridae, Pangasiidae, Siluridae and Tetraodontidae with three species each.

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For Southeast Asia, delineations were determined using a bottom-up approach that employed both published and unpublished field data and expert assessment (Abell et al. 2008; Inger & Chin 1962; Martin-Smith & Tan 1998).  This ecoregion is characterized by a relatively depauperate fauna, with a relatively high endemism ratio. When more accurate data become available, the region may need to be divided further into possibly a western and eastern slope (M. Kottelat pers. comm. 2006).


  • 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.
  • World Wildlife Fund (WWF) (2001) \Terrestrial Ecoregions of the World\ "<"">"
  • Inger, R. F. and Chin, P. K. (1962). "Freshwater fishes of North Borneo" Fieldiana Zoology 45 pp. 1-268.
  • Martin-Smith, K.M.;H.H. Tan (1998). "Diversity of freshwater fishes from eastern Sabah: annotated checklist for Danum valley and a consideration of inter- and intra-catchment variability" Raffles Bull. Zool 46 (2) pp. 573-604.