Chapter 8 - Fish Diversity in the Mekong River Basin

Abstract

The Mekong Fish Database developed by the Mekong River Commission provides the most comprehensive data source on Mekong fishes, although it does not include any information on species from areas upstream of Yunnan and in Myanmar. Current speed and channel morphology change as the Mekong River flows downstream affect the species that favor specific parts of the river, and the upper and lower reaches of the Mekong harbor different fish faunas. The Mekong River mainstream and the lowland sections of tributaries are highly turbid during the flood season because of the heavy sediment load. Catfishes are well adapted to this environment with their sensitive barbels that allow them to locate food without the help of their eyes. The threadfins use their filamentous pectoral fins in a similar way and both groups are well adapted to an environment with almost no light penetration. Some species that show preference for certain parts of the mainstream are the endemic Mekongina erythrospila and Labeo dyocheilus that have a preference for fast-flowing water and are rare or absent downstream of Kratie where there are no rapids.