Dasyatis laosensis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	RAJIFORMES	DASYATIDAE

Scientific Name:

Dasyatis laosensis

Species Authority:

Roberts & Karnasuta,1987

Common Name/s:

English

–

Mekong Freshwater Stingray

Assessment Information [top]

Red List Category & Criteria:

Endangered A2cde+3cde; B1ab(iii,v) ver 3.1

Year Assessed:

2005

Assessor/s

Compagno, L.J.V.

Evaluator/s:

Musick, J.A. & Fowler, S.L. (Shark Red List Authority)

Justification:
The Mekong Freshwater Stingray (Dasyatis laosensis) is an obligate freshwater stingray with a limited distribution in just two rivers in Southeast Asia (Mekong and Chao Phraya). It is under heavy (incidental) fishing pressure and, more importantly, it is being affected by habitat degradation on a massive scale.

History:

2000

–

Endangered

Geographic Range [top]

Range Description:	This stingray is known from the Mekong River at the border between Laos and Thailand, ,and the Chao Phraya River near Chai Nat in Thailand. These two locations are presumed to support isolated subpopulations.
Countries:	Native: Lao People's Democratic Republic; Thailand

Population [top]

Population Trend:	Decreasing

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	This species is restricted to freshwater habitats. Very few specimens are known and only seven are deposited in museum collections. Little life history information is available for this species, other than that a single pup was born in captivity at Chai Nat, Thailand (see below).
Systems:	Freshwater

Threats [top]

Major Threat(s):	This species is subjected to heavy fishing pressure, being taken as bycatch of intensive fisheries for freshwater teleosts in the large rivers where it occurs. Young are sufficiently small to be suitable for the aquarium trade, but it is not known if this species is collected. More importantly, the Mekong stingray is being subjected to massive habitat degradation, through dam-building and pollution from agricultural and industrial development, which has apparently drastically decreased fish diversity in the rivers where this stingray occurs. Its population is supposed to have declined as a result and this decline in numbers is projected to continue (Roberts and Karnasuta 1987, Cook and Compagno 1994, Compagno and Cook 1995b).

Major Threat(s):

This species is subjected to heavy fishing pressure, being taken as bycatch of intensive fisheries for freshwater teleosts in the large rivers where it occurs. Young are sufficiently small to be suitable for the aquarium trade, but it is not known if this species is collected. More importantly, the Mekong stingray is being subjected to massive habitat degradation, through dam-building and pollution from agricultural and industrial development, which has apparently drastically decreased fish diversity in the rivers where this stingray occurs. Its population is supposed to have declined as a result and this decline in numbers is projected to continue (Roberts and Karnasuta 1987, Cook and Compagno 1994, Compagno and Cook 1995b).

Conservation Actions [top]

Conservation Actions:	There is no in situ protection for the species or its habitat. The Thai government started a project in the 1990s to breed this and other freshwater stingrays in captivity at Chai Nat above the dam on the Chao Phraya River to counter declines of freshwater rays in the river. The project was visited by S. Cook, S. Fowler and the author from the IUCN/SSC Shark Specialist Group in 1993, when four specimens of this ray were seen (including adults and a newborn specimen born in captivity) along with the Giant Freshwater Stingray (Himantura chaophraya), Longnose Marbled Whipray (H. oxyrhyncha) and White-edge Freshwater Whipray (H. signifer). We later (1996) learned that the project had been put on hold, at least temporarily.

Conservation Actions:

There is no in situ protection for the species or its habitat. The Thai government started a project in the 1990s to breed this and other freshwater stingrays in captivity at Chai Nat above the dam on the Chao Phraya River to counter declines of freshwater rays in the river. The project was visited by S. Cook, S. Fowler and the author from the IUCN/SSC Shark Specialist Group in 1993, when four specimens of this ray were seen (including adults and a newborn specimen born in captivity) along with the Giant Freshwater Stingray (Himantura chaophraya), Longnose Marbled Whipray (H. oxyrhyncha) and White-edge Freshwater Whipray (H. signifer). We later (1996) learned that the project had been put on hold, at least temporarily.

Citation:	Compagno, L.J.V. 2005. Dasyatis laosensis. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>. Downloaded on 10 February 2010.
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