DOI: 10.1111/j.1472-4642.2006.00311.x © 2007 The Authors 172 www.blackwellpublishing.com/ddi Journal compilation © 2007 Blackwell Publishing Ltd Diversity and Distributions, (Diversity Distrib.) (2007) 13, 172–184 BIODIVERSITY RESEARCH ABSTRACT Freshwater finfish species richness and level of endemism in East, and South and South-East Asia that included 17 nations were studied using available databases, and included nation-wise distribution, habitat types, and conservation status. The number of endemic finfish species in the region was 559, belonging to 47 families. Families Cyprinidae and Balitoridae accounted for 43.5% and 16.2% of the total number of endemic species in the region, respectively, followed by Sisoridae (25), Gobiidae (20), Melanotaeniidae (19), and Bagridae (16), and the other 41 families had at least one endemic species. Nation-wise the most number of endemic fresh- water finfish species occur in India (191), followed by China (88), Indonesia (84), and Myanmar (60). In India, the endemic species accounted for 26.4% of the native freshwater fish fauna, followed by South Korea (16.9%), the Philippines, (16.3%) and Myanmar (15.7%). Statistically significant relationships discerned between the number of indigenous and endemic species richness to land area (X la in 10 3 km 2 ) of the nations in the region were, Y in = 218.961 Ln(X la ) – 843.1 (R 2 = 0.735; P < 0.001) and Y e = 28.445 Ln X la - 134.47 (R 2 = 0.534; P < 0.01), respectively, and between indigenous and endemic species richness was Y e = 0.079X n - 1.558 (R 2 = 0.235; P < 0.05). The overall conservation status of endemic finfish in Asia was satisfactory in that only 92 species were in some state of vulnerability, of which 37 species (6.6%) are endangered or critically endangered. However, the bulk of these species (83.7%) were cave- and or lake-dwelling fish. However, nation-wise, the endemic freshwater finfish fauna of the Philippines and Sri Lanka, based on the imperilment index, were found to be in a highly vulnerable state. Among river basins, the Mekong Basin had the highest number of endemic species (31.3%). The discrepancies between data- bases are highlighted and the need to consolidate information among databases is discussed. It is suggested that the Mekong Basin be considered as a biodiversity hotspot, and appropriate management strategies be introduced in this regard. Keywords Asia, native species richness, endemic species, river basins, conservation status, habitats. INTRODUCTION Fish as a group, apart from its food value (Delgado et al., 2003), from a biodiversity viewpoint, has the highest species diversity among all vertebrate taxa, currently estimated to number 28,800 (www.FishBase.org). Of the known fish species, about 40% are freshwater species, with about another 500 – 600 species requiring freshwater at some stage in their life cycle (Kottelat & Whitten, 1996). The Earth is estimated to have only 35,029,000 km 3 of fresh- water, or only 2.5% of all water resources, of which only 23.5% is habitable (Shiklomanov, 1993, 1998; Smith, 1998). The naturally available freshwater in the form of rivers, lakes, wetlands, etc. amounts only to 0.01% of the Earth’s water resources or only 113,000 km 3 . Generally, a fact that is often not appreciated is that, of the world water resources, less than 0.01% occurs as surface waters, but it is the home to a very high level of biodiversity, accounting for nearly 25% of global vertebrate diversity, sup- ported through a number of freshwater ecosystems, rivers, lakes, marshes, and seasonal or ephemeral wetlands; but these also happen to be among the world’s most threatened ecosystems (Groombridge, 1992). It has been suggested that global freshwater biodiversity is declining at far greater rates than is true for even the most affected terrestrial ecosystems (Ricciardi & Rasmussen, 1999). 1 School of Life and Environmental Sciences, Deakin University, PO Box 423, Warrnambool, Victoria 3280, Australia; and 2 Network of Aquaculture Centres in Asia-Pacific, PO Box 1040, Kasetsart Post Office, Bangkok 10903, Thailand *Correspondence: Sena S. De Silva, Network of Aquaculture Centres in Asia-Pacific, PO Box 1040, Kasetsart Post Office, Bangkok 10903, Thailand. Fax: +66-2-561-1727, E-mail: sena.desilva@enaca.org 3 Present address: Primary Industries Research Victoria, Snobs Creek, Alexandra, Victoria, Australia 3714 Blackwell Publishing, Ltd. Endemic freshwater finfish of Asia: distribution and conservation status Sena S. De Silva 1,2 *, Nigel W. Abery 1,3 and Thuy T. T. Nguyen 2