Aaptosyax grypus

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	ACTINOPTERYGII	CYPRINIFORMES	CYPRINIDAE

Scientific Name:

Aaptosyax grypus

Species Authority:

Rainboth, 1991

Common Name/s:

English

–

Mekong Giant Salmon Carp

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered A2acd ver 3.1

Year Published:

2011

Assessor/s:

Vidthayanon, C.

Reviewer/s:

Ng, H.H., Rainboth, W., Kottelat, M., Kullander, S.O., Parenti, L. & Allen, D.

Contributor/s:

Justification:
The Mekong Giant Salmon Carp has a wide range within the Mekong River, but is now present at very low densities in both adult and juvenile forms. Its population has been much reduced (by more than 90%) over the last decade (C. Vidthayanon, pers. comm.), as a result of overfishing and habitat degradation. The species is therefore assessed as Critically Endangered. This fish is also likely to be impacted in the future by development of mainstream dams, which will further limit its breeding success.

History:

1996

–

Data Deficient

Geographic Range [top]

Range Description:	This species is endemic to the Mekong River basin, occurring from Lao PDR to northern Cambodia. It was described from a specimen taken from the Mekong at the entrance to the Mun River, Thailand. The Mekong Giant Salmon Carp once occurred from the Lower Mekong, through the Khorat Plateau to Phnom Penh, but has recently been seen from Chiang Rai in northern Thailand (unconfirmed record). Its current distribution is northeastern Thailand and central Lao PDR, restricted to larger parts of rivers.
Countries:	Native: Lao People's Democratic Republic Possibly extinct: Cambodia; Thailand
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The species was once widespread in the mainstream Mekong River, but naturally rare and has been much reduced in recent years (Rainboth 1996). Its range has reduced and now larger individuals are very rarely found. It is rare in Lao PDR, and has likely disappeared from Thailand. Its population has reduced over the last decade by more than 90% (C. Vidthayanon, pers. comm.) as a result of overfishing and habitat degradation.
Population Trend:	Decreasing

Population:

The species was once widespread in the mainstream Mekong River, but naturally rare and has been much reduced in recent years (Rainboth 1996). Its range has reduced and now larger individuals are very rarely found. It is rare in Lao PDR, and has likely disappeared from Thailand. Its population has reduced over the last decade by more than 90% (C. Vidthayanon, pers. comm.) as a result of overfishing and habitat degradation.

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	The species mainly inhabits mainstreams, and frequently enter large tributaries. Breeds in summer, in clear water around rocky rapids in the Thai-Lao border. Breeds in faster flowing water/rapids.
Systems:	Freshwater

Threats [top]

Major Threat(s):	Local overfishing (especially through drift gill nets), illegal fishing (explosives) impact its populations, and hydrographic change due to mainstream dams and climate change threaten its survival and recruitment. There are three further dams planned in the Thai part of the Mekong, within the species current distribution.

Major Threat(s):

Local overfishing (especially through drift gill nets), illegal fishing (explosives) impact its populations, and hydrographic change due to mainstream dams and climate change threaten its survival and recruitment. There are three further dams planned in the Thai part of the Mekong, within the species current distribution.

Conservation Actions [top]

Conservation Actions:	Life history and population research are needed. Research is needed into population and habitat trends.

Conservation Actions:

Life history and population research are needed. Research is needed into population and habitat trends.

Citation:	Vidthayanon, C. 2011. Aaptosyax grypus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 May 2013.
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