Mekong River - A Global Ecoregion

Most diverse and distinctive large river fauna of tropical Asia

Snapshot: Ecoregion 144

Size:
More than 2,600 miles long (4,300 kilometers)

Habitat type:
Large Rivers

Geographic Location: Cambodia, China, Laos, Myanmar, Thailand, Vietnam

Conservation Status:
Vulnerable

Did You Know!

Both the giant barb and the giant Mekong catfish grow to be up to 10 feet long!

About the Area
The Mekong starts among the glaciers of Tibet and ends by flowing into the South China Sea. It is the longest river in Southeast Asia and the tenth longest in the world.

The mighty Mekong is an important source of water for people in six countries and forms the border between three. The Mekong is also the source of life for many unusual species of fish and other animals.

Local Species
Some of the Mekong's 240 species of fish migrate long distances against currents to reach other parts of the river to spawn. The Laotian shad (freshwater herring) can be found up to 2,000 km upstream from the ocean, but unfortunately it is endangered, with the last known migration occurring in 1984.

Among the numerous endemic fish species, one of the most imperiled and extraordinary is the giant Mekong catfish (Pangasianodon gigas), which can grow to over 300 kilograms and may have historically migrated up to 2000 kilometers. Other endemic fish that are under threat are Mae Khong herring (Tenualosa thibaudeaui), Thicklip barb (Probarbus labeamajor), and a cave fish (Barbus speleops).

This ecoregion is a major wintering area for the endangered Siberian crane (Grus leucogeranus) and Swan goose (Anser cygnoides), and is home to Sarus crane (Grus antigone). Also found here are 100 endemic snail species. The Mekong basin also provides habitat for the endangered Irrawaddy dolphin (Orcaella brevirostris).

Threats
The Mekong River system suffers from a wide range of serious threats such as:

• Deforestation that has changed runoff patterns and increased sedimentation.
• Modification of the hydrologic regime by flood control schemes, water diversions, and a vast array of hydropower projects.
• Impoundments that block the movements of the ecoregion's numerous migratory fish species.
• Over fishing, particularly with the increased use of poisons.
• Urban, industrial, and agricultural pollution that are largely untreated.