The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the sixth longest in Asia. Its estimated length is 4,909 km (3,050 mi), and it drains an area of 795,000 km2 (307,000 sq mi), discharging 475 km3 (114 cu mi) of water annually. From the Tibetan Plateau the river runs through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. The extreme seasonal variations in flow and the presence of rapids and waterfalls in the Mekong make navigation difficult. Even so, the river is a major trade route between western China and Southeast Asia.
Tonlé Sap is a seasonally inundated freshwater lake, Tonlé Sap Lake, and an attached river, the 120 km (75 mi) long Tonlé Sap River, that connects the lake to the Mekong River. They form the central part of a complex hydrological system, in the 12,876 km2 (4,971 sq mi) Cambodian floodplain covered with a mosaic of natural and agricultural habitats that the Mekong replenishes with water and sediments annually. The central plain formation is the result of millions of years of Mekong alluvial deposition and discharge. From a geological perspective, the Tonlé Sap Lake and Tonlé Sap River are a current freeze-frame representation of the slowly but continuously shifting lower Mekong basin. Annual fluctuation of the Mekong's water volume, supplemented by the Asian monsoon regime, causes a unique flow reversal of the Tonlé Sap River. The largest freshwater lake in Southeast Asia, it contains an exceptional large variety of interconnected eco-regions with a high degree of biodiversity and is therefore a biodiversity hotspot. It was designated a UNESCO biosphere reserve in 1997.
The Irrawaddy dolphin is a euryhaline species of oceanic dolphin found in discontinuous subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. It closely resembles the Australian snubfin dolphin and was not described as a separate species until 2005. It has a slate blue to a slate gray color and are a part of genus Orcaella which is also known as snubfin dolphins. Although found in much of the riverine and marine zones of South and Southeast Asia, the only concentrated lagoon populations are found in Chilika Lake in Odisha, India and Songkhla Lake in southern Thailand.
The iridescent shark,iridescent shark catfish or tra catfish is a species of shark catfish native to the rivers of Southeast Asia. Despite its name, it is not a shark. It is found in the Mekong basin as well as the Chao Phraya River, and is heavily cultivated for food there.
The Khone Falls and Pha Pheng Falls together form a waterfall located in Champasak Province on the Mekong River in southern Laos, near the border with Cambodia. At 10,782 metres wide, it is the widest waterfall in the world.
The Mekong giant catfish, is a large, critically endangered species of catfish in the shark catfish family (Pangasiidae), native to the Mekong basin in Southeast Asia and adjacent China. It is considered critically endangered due to accelerating habitat loss.
The giant barb, Siamese giant carp, or simply Siamese carp, is the largest species of cyprinid in the world. These migratory fish are found only in the Mae Klong, Mekong, and Chao Phraya River basins in Indochina. Populations have declined drastically due to habitat loss and overfishing, and the giant barb is now considered critically endangered.
Macrognathus is a genus of eel-like fish of the family Mastacembelidae of the order Synbranchiformes.
The giant salmon carp, also termed the Mekong giant salmon carp, is a species of freshwater fish in the family Cyprinidae and the single species in the monotypic genus Aaptosyax. It is endemic to the middle reaches of the Mekong River in northern Cambodia, Laos and Thailand. Its population is much reduced (>90%) as a result of overfishing and habitat degradation, and it is now considered Critically Endangered.
The Mekong freshwater stingray, Hemitrygon laosensis, is a species of stingray in the family Dasyatidae, restricted to the Mekong and Chao Phraya Rivers in Laos and Thailand; the occurrence in Chao Phraya is considered an introduction. Measuring up to 62 cm (24 in) across, this ray has an oval pectoral fin disc, a tail with both upper and lower fin folds, and a midline row of spine-like dermal denticles. A characteristic feature of this species is its bright orange underside. The Mekong freshwater stingray preys on invertebrates and is aplacental viviparous. It has been assessed as Endangered by the International Union for Conservation of Nature (IUCN), as it is threatened by overfishing and habitat degradation.
Macrognathus siamensis is a tropical fish belonging to the family Mastacembelidae.
Schistura khamtanhi is a species of ray-finned fish in the genus most speciose genus in the stone loach family, Schistura. It is found in the Kong River basin in Laos and in the main Mekong river in Cambodia and Laos where it is abundant, being an important quarry species for the fish traps at Kohne Falls. It inhabits rapids and Sony bottomed stretches of the main Mekong and its tributaries and it migrates past the Kohne Falls in January and February annually. It is the only member of the genus Schistura which is known to be migratory. The specific name honours Khamtanh Vatthanatham, a Fisheries Programme Officer of the Mekong River Commission who was very helpful to the Maurice Kottelat during his 1999 survey, in which this species was discovered.
Parasikukia maculata is a species of cyprinid fish which is found in the Mekong in Thailand, Laos and Cambodia as well as the Mae Klong, Chao Phraya and south eastern river systems in Thailand and the westward drainages of the Cardamom Hills in Cambodia. It is the only member of its genus.
Oryzias mekongensis is a species of fish in the family Adrianichthyidae. It is endemic to the Mekong River Basin in southeast Asia, where found in ditches, canals and ponds.
Pao turgidus is a species of freshwater pufferfish native to the Mekong basin. It may also occur in the Chao Phraya basin in Thailand. This species grows to a length of 18.5 centimetres (7.3 in) SL.
Paralaubuca typus is a species of freshwater ray-finned fish from the carp and minnow family Cyprinidae from south-east Asia. It is found in Thailand in the basins of the Chao Phraya, Tapi, Mekong and Mae Klong and in the Mekong on Laos and Cambodia, as well as Vietnam where it is also found in the La Ngà River. It is one of the most abundant fish species in the lower Mekong.
The elephant ear gourami is a large species of gourami native to the Mekong in Thailand, Laos, and Cambodia.
Parambassis siamensis is a species of freshwater fish in the Asiatic glassfish family Ambassidae. It is native to the mainland Southeast Asia in Thailand, Cambodia, Vietnam, and Laos; records from Singapore and Java (Indonesia) probably are introductions. Its range includes the Mekong, Mae Klong, and Chao Phraya basins. It grows to 7.5 cm (3.0 in) standard length, although typical length is about 4 cm (1.6 in).
Hemibagrus filamentus is a species of catfish endemic to Cambodia, Laos and Thailand, known only from Mekong River. It is found in still waters and moving waters although it also been found in large rivers. It feeds on fishes, crustaceans, aquatic insect larvae and plant material. When migrating, it moves into smaller tributaries and in flooded areas with rising water level; they spawn from June to July. It is listed as a junior synonym of H. nemurus and research is often confused with H. nemurus. It is fished for food by small-scale commercial fisheries but exact threats are unknown and nothing else is known about this fish thus the Data Deficient listing.
Macrognathus zebrinus, the zebra spiny eel, is a species of spiny eel endemic to Myanmar, specifically known from the Irrawaddy River, Sittaung River and Salween River and may also occur in Indonesia. It was originally described as Mastacembelus zebrinus before being moved to the genus Macrognathus in 1984 and 1986.
