|Scientific Name:||Yasuhikotakia nigrolineata|
|Species Authority:||(Kottelat & Chu, 1987)|
Botia nigrolineata Kottelat & Chu, 1987
|Taxonomic Notes:||The species has long been misidentified as Botia sidthimunki or Y. sidthimunki.|
|Red List Category & Criteria:||Vulnerable A2bde ver 3.1|
|Reviewer/s:||Kottelat, M. & Allen, D.|
The species has a relatively wide geographical distribution in the Mekong drainage (from southern Yunnan to at least the Se Kong drainage in southern Lao PDR), and is also recorded from the Nan River drainage in northern Thailand, however the species has only been recorded from five locations in the Mekong and Nan river drainages (the Nan River, the upper Xebangfai, the Xe Kong, the Mun River, and the Mekong drainage in Yunnan), although it is possible that the species may be found at more locations within this range. Populations in the Nan drainage in Thailand are thought to have declined as a result of exploitation and habitat degradation (C. Vidthayanon pers. comm. 2012), and recent surveys (C. Vidthayanon pers. comm. 2012) did not record the species, although further research is required to confirm the species' status in the drainage. The species is often present at low densities, is not easily surveyed for, and has been misidentified in the past. With the exception of the Xe Kong (surveyed in 1999 and 2009, when it was found at the same low densities of one to three specimens per sampling station; M. Kottelat pers. comm. 2012) and the Nan River drainage, none of the known locations are know to have been sampled twice. The population status of the species' sub-populations in the Nan, Mun and upper Mekong (at Xishuanbanna) rivers is uncertain as a result of known threats at these locations.
The species is likely to be impacted by sedimentation throughout its range, and by hydropower development in parts of its range (e.g., the Se Kong River in Lao PDR, and the Mun River in Thailand), with over-collection and habitat degradation present in other parts of the species range.
The population of the species is expected to have declined by at least 30% across its range within the last ten years, based on the apparent decline of the species from the Nan River drainage, and threats (exploitation, as well as habitat degradation) present at other known locations, whilst the Area of Occupancy is inferred to have declined as a result of these threats, especially dam development. The species is assessed as Vulnerable on the basis of this suspected decline in population across the species range.
Further research is required to confirm the species' current distribution and population trends across its range, and it should be reassessed if presence at further locations, or greater declines at the known locations, is confirmed.
|Range Description:||The species is known from a small number of records in larger tributaries in the Mekong drainage in Lao PDR (e.g., the upper Xe Bangfai (Kottelat 1998), and the Xe Kong drainage (Kottelat 2011)), Thailand (e.g., the lower Mun River; M. Kottelat pers. comm. 2012), and southern China (Xishuangbanna Prefecture, Yunnan; Kottelat and Chu 1987). The species is also known from the Nan River, a tributary of the Chao Phraya in northern Thailand, however a recent survey (March-April 2012) at five localities in Nan River tributaries did not find the species (C. Vidthayanon pers. comm. 2012), although others report that the species is still present in the upper parts of the Nan drainage (M. Kottelat pers. comm. 2012). Further appropriate survey work is required to determine the species' presence in the drainage.
The species is currently known from only five populations, but may be present at further locations within the currently known extent as the species is usually present at low densities and is hard to collect in surveys (M. Kottelat pers. comm. 2012); it is apparently present at patchy and low densities, with a few areas of higher density.
Native:China (Yunnan); Lao People's Democratic Republic
|Range Map:||Click here to open the map viewer and explore range.|
The species is usually present at low densities and is hard to collect in surveys. The species had previously been found in and easily obtainable for the aquarium trade (in 2001) in the upper Nan River (M. Kottelat pers. comm. 2012), and in surveys undertaken during 1995-2003, when the species was found in the Nan drainage e.g., in the Nam Wa and Mae Jarim streams, where it was common. However, a survey in 2012 did not record the species in the drainage (C. Vidthayanon pers. comm. 2012).
There is no information on the species' population trend in other parts of the species range. With the exception of the Xe Kong (surveyed in 1999 and 2009, when it was found at the same low densities of one to three individuals per sampling station; M. Kottelat pers. comm. 2012) and the Nan River drainage, none of the known locations have been sampled twice. The population trends of the species' sub-populations in the Nan, Mun and upper Mekong (at Xishuanbanna) rivers is uncertain as a result of known threats at these locations.
Given the lack of repeated survey at most of the known locations, estimating population declines is problematical, however a decline of at least 30% within the last ten years across the species' range is suspected based on the presence of known threats and inference from the recent survey in the Nan River drainage.
|Habitat and Ecology:||This species occurs in riffles, in clear, fast-flowing water (Kottelat 1998). It is found in small streams with sandy bottom and moderate current (Kottelat and Chu 1987) in the upper parts of rivers.|
|Major Threat(s):||The known distribution of the species is very fragmented, with the Xe Kong population likely to be impacted by hydropower projects, with all known sampling sites on the river downstream of existing or planned dams, and consequential impacts from construction activities or water diversion. In the Mun River the species is likely to have been heavily impacted by dam development and pollution from agricultural sources, with consequential impacts on the species' population there. The species will be impacted by pollution (sedimentation from agricultural activities and from forest clearance) across its range.|
|Conservation Actions:||The species has been assessed as 'Endangered' in Thailand (Vidthayanon 2005), and it has been proposed that it should be reassessed as 'Critically Endangered' there as a result of recent survey in the Nan River drainage (C. Vidthayanon pers. comm. 2012).|
IUCN. 2012. IUCN Red List of Threatened Species (ver. 2012.1). Available at: http://www.iucnredlist.org. (Accessed: 19 June 2012).
Kottelat, M. 1998. Fishes of the Nam Theun and Xe Bangfai basins, Laos, with diagnoses of twenty-two new species (Teleostei: Cyprinidae, Balitoridae, Cobitidae, Coiidae and Odontobutidae). Ichthyological Exploration of Freshwaters 9(1): 1-128.
Kottelat, M. and Chu, X. 1987. The botiine loaches (Osteichthyes: Cobitidae) of the Lancangjiang (Upper Mekong) with description of a new species. Zoological Research 8(4): 393-400.
Vidthayanon, C. 2005. Thailand Red Data: Fishes. ffice of Natural Resources and Environmental Policy and Planning, Bangkok.
|Citation:||Vidthayanon, C. 2012. Yasuhikotakia nigrolineata. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 09 March 2014.|
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