Mekong freshwater stingray  (Dasyatis laosensis)

The Mekong freshwater stingray is classified as Endangered (EN) on the IUCN Red List (1).

The Mekong freshwater stingray (Dasyatis laonenis) shows a vibrant orange colour on its upper surface (3) with a more uniform brown colour on the underside (4). The slim tail of the Mekong freshwater stingray is nearly twice the size of the width of its disc shaped body, a unique trait specific to this species (5).

Not much else is known about the Mekong freshwater stingray, but like other species of the Dasyatidae family, a group of whiptailed stingrays (6), the head, body and pectoral fins of the Mekong freshwater stingray are fused to a flattened round disc with a long, lean tail (7).

The Mekong freshwater stingray has a very restricted range, only being found in two Southeast Asian rivers: the Mekong river and the Chao Phraya river (4). The Mekong freshwater stingray has been found as far north as the Chiang Rai province in Thialand and as far south as Stung Treng in Cambodia, though its range may well extend down to the Mekong delta. It is thought to have been introduced to the Chao Phraya river (1).

As its name suggests, the Mekong freshwater stingray only inhabits freshwater rivers (4). It is a river-bed-dwelling species, preferring rocky or sandy bottoms in moderately fast-flowing water (1).

Little is known about the Mekong freshwater stingray. Other species in the genus Dasyatis will typically incubate the eggs of their young inside their bodies until the embryos have fully developed and are ready to hatch (8).

The diet of most species of whiptailed stingray consists of small fish and invertebrates that inhabit the river bed (5) (7). 

One major cause for the decline of the Mekong freshwater stingray is thought to be intensive fishing within its habitat. Though not directly fished, this species is often found in fishing nets as unwanted bycatch (1).

Increased industrial and agricultural development also presents a danger to the Mekong freshwater stingray population through habitat loss (4). Building projects may contribute to an increase in water pollution (1), while plans to build dams on the Mekong river and its tributaries are also predicted to exacerbate the decline of this species by isolating and splitting populations (4). The total population of the Mekong freshwater stingray is thought to have declined by roughly 50 percent in the last 20 years (1).

One major cause for the decline of the Mekong freshwater stingray is thought to be intensive fishing within its habitat. Though not directly fished, this species is often found in fishing nets as unwanted bycatch (1).

Increased industrial and agricultural development also presents a danger to the Mekong freshwater stingray population through habitat loss (4). Building projects may contribute to an increase in water pollution (1), while plans to build dams on the Mekong river and its tributaries are also predicted to exacerbate the decline of this species by isolating and splitting populations (4). The total population of the Mekong freshwater stingray is thought to have declined by roughly 50 percent in the last 20 years (1).

Recommended conservation measures for the Mekong freshwater stingray include further research into its behaviour, life cycle and ecology as well as increased protection (9). 

Find out more about the Mekong freshwater stingray:

• FishBase
  http://www.fishbase.org/summary/speciessummary.php?id=15389