''Hucho bleekeri'', the Sichuan taimen, is a

species In biology, a species is the basic unit of 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 individuals of the appropriate s ...

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels of s ...

in the

salmon Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

(

Salmonidae Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

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 ...

basin in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. Their typical habitat includes mountain streams and small rivers, typically being found in the catchment areas of the

Dadu River The Dadu River (), known in Tibetan as the Gyelmo Ngul Chu, is a major river located primarily in Sichuan province, southwestern China. The Dadu flows from the eastern Tibetan Plateau into the Sichuan Basin where it joins with the Min River, a t ...

Sichuan Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

and

Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest po ...

Provinces, as well as the Hanjiang River. This particular fish population is largely threatened by

habitat loss Habitat 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 ...

and

illegal fishing Illegal, unreported and unregulated fishing (IUU) is an issue around the world. Fishing industry observers believe IUU occurs in most fisheries, and accounts for up to 30% of total catches in some important fisheries. Illegal fishing takes pl ...

, resulting in a " critically endangered" conservation status from the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

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.Song, Z. 2012
''Hucho bleekeri''
In:

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

of Threatened Species. Version 2012.2. . Downloaded on 26 October 2012.

Distribution and habitats

Sichuan taimen are

to the

basin in

. They are found in the upper tributaries of the Yangtze River in

Sichuan Province Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

, the upper and middle reaches of the

in Sichuan and

Provinces, and the upper reaches of the Hanjiang River south of the

Qin Mountains The Qinling () or Qin Mountains, formerly known as the Nanshan ("Southern Mountains"), are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow ...

Shaanxi Province Shaanxi (alternatively Shensi, see § Name) is a landlocked province of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E), Henan (E), Hubei (SE), Chongqing (S), Sichuan (SW), Gansu (W), Ningx ...

. 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 Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and insects, while adults are largely

piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

Threats

According to the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

, 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.

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 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

Appearance

Distribution and habitats

Diet

Threats

See also

References