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''Hucho bleekeri'', the Sichuan taimen, is a
species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...
of
freshwater fish are common freshwater fish throughout temperate Eurasia. Freshwater fish are those that spend some or all of their lives in fresh water, such as river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, s ...
in the
salmon Salmon is the common name for several species of ray-finned fish in the family (biology), family Salmonidae. Other fish in the same family include trout, Salvelinus, char, Thymallus, grayling, and Freshwater whitefish, whitefish. Salmon are n ...
family In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of families is to maintain the well-being of its members an ...
(
Salmonidae Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes . It includes salmon, trout, chars, freshwater whitefishes, and Thymallus, graylings, which collectively are known as the salmonid ...
),
endemic Endemism is the state of a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest grou ...
to the
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Asia, the third-longest in the world and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows in a ...
basin in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the List of countries and dependencies by population, world's most populous country, with a population of around 1.4 billion. Covering approximately 9.6& ...
. Their typical habitat includes mountain streams and small rivers, typically being found in the catchment areas of the Dadu River in
Sichuan Sichuan (, Standard Chinese, Standard Mandarin pronunciation: ; Postal romanization, alternatively romanized as Szechuan or Szechwan) is a landlocked Provinces of China, province in Southwest China occupying most of the Sichuan Basin and the ...
and
Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also called Kokonur, is a landlocked province A province is almost always an administrative division within a country or state. The term derives from the ancient Roman '' provinci ...
Provinces, as well as the Hanjiang River. This particular fish population is largely threatened by
habitat lossHabitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby reduc ...
and illegal fishing, resulting in a " critically endangered" conservation status from the
International Union for Conservation of Nature International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * International (The Three D ...
.


Appearance

The vertebrates have a dark Gray back, silvery white underside, and small cross-shaped spots across the body and gill cover. Adults can grow up to in length.


Distribution and habitats

Sichuan taimen are
endemic Endemism is the state of a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest grou ...
to the
Yangtze The Yangtze or Yangzi ( or ) is the longest river in Asia, the third-longest in the world and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows in a ...
basin in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the List of countries and dependencies by population, world's most populous country, with a population of around 1.4 billion. Covering approximately 9.6& ...
. They are found in the upper tributaries of the Yangtze River in Sichuan Province, the upper and middle reaches of the Dadu River in Sichuan and
Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also called Kokonur, is a landlocked province A province is almost always an administrative division within a country or state. The term derives from the ancient Roman '' provinci ...
Provinces, and the upper reaches of the Hanjiang River south of the Qin Mountains in
Shaanxi Province Shaanxi (, ; Chinese postal romanization, alternately Shensi) is a landlocked Provinces of China, province of the China, People's Republic of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E ...
. It dwells predominantly in fast-flowing streams with sandy and gravel substrates. The species prefers mountain brooks at meters above sea level with high dissolved oxygen (>5 mg/l) and a low water temperature (less than ).Hu et al. 2008. "Threatened fishes of the world: ''Hucho bleekeri'' Kimura, 1934 (Salmonidae)." ''Environmental Biology of Fishes'' 82.4: 385-386.


Diet

Juveniles feed mostly on zooplankton and insects, while adults are largely piscivorous.


Threats

According to the IUCN, the Sichuan taimen is threatened mostly by habitat loss from the construction of hydropower stations, erosion of soil due to deforestation, road construction, and sand excavation. Despite legal protections, the species is also threatened by illegal fishing. Recent studies have estimated the species has endured a 50-80% decline in population over the past three generations, and the decline is expected to continue. Only an estimated 2,000-2,500 mature individuals survive.Song, Z. 2012
''Hucho bleekeri''
In: IUCN Red List of Threatened Species. Version 2012.2. . Downloaded on 26 October 2012.


See also

* List of endangered and protected species of China


References

*Kimura, S. (1934
Description of the fishes collected from the Yangtze-kiang, China, by late Dr. K. Kishinouye and his party in 1927-1929
''The Journal of the Shanghai Science Institute, Section III. Vol. I,'' 11-247. (original description) {{Taxonbar, from=Q3272198 Hucho, bleekeri Endemic fauna of China Freshwater fish of China Yangtze River Critically endangered fish Critically endangered fauna of Asia Fish described in 1934 Species endangered by damming Species endangered by habitat loss