Hucho bleekeri

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Hucho bleekeri
チ ョ ウ コ ウ イ ト ウ (Hucho bleekeri) .jpg

Hucho bleekeri

Systematics
Cohort : Euteleosteomorpha
Order : Salmonid fish (Salmoniformes)
Family : Salmon fish (Salmonidae)
Subfamily : Salmoninae
Genre : Hucho
Type : Hucho bleekeri
Scientific name
Hucho bleekeri
Kimura , 1934

Hucho bleekeri (Engl .: Sichuan taimen ) is a species of freshwater fish from the family of salmon fish ( Salmonidae ) thatare endemic to the Yangtze River Basin in China . Their typical habitat includes mountain streams and small rivers, which are typically found in the catchment areas of the Dadu River in the provinces of Sichuan and Qinghai, and the Han Jiang River . This particular fish population is largely threatened by habitat loss and illegal fishing, leading to a "critically endangered" conservation status by the International Union for Conservation of Nature (IUCN) .

Appearance

The vertebrates have a dark gray back, a silvery-white underside and small cross-shaped spots scattered all over their body and on the gill cover . The upper jaw is slightly longer than the lower jaw; the upper jaw runs to the back of the eye; Adults have an average length of 28 cm and can be up to 64 cm long.

Distribution and habitats

Sichuan taimen are endemic to the Chinese Yangtze River basin. They occur in the upper tributaries of the Yangtze River in Sichuan Province , on the upper and middle reaches of the Dadu River in the provinces of Sichuan and Qinghai, and on the upper reaches of the Han Jiang River south of the Qin Mountains in Shaanxi Province . It lives mainly in fast flowing rivers with sand and gravel substrates . The species prefers mountain streams at 700–3,300 m above sea ​​level with a high oxygen content (> 5 mg / l) and a low water temperature (less than 15 ° C).

nutrition

The juvenile fish feed mainly on zooplankton and insects , while the adults mostly eat other fish .

Danger

According to the IUCN , Sichuan Taimen is primarily threatened by the loss of habitat due to the construction of hydropower plants , soil erosion from deforestation , road construction and sand excavation. Despite the legal protection, the species is also threatened by illegal fishing . Recent studies have estimated that the species has suffered a population decline of 50-80% over the past three generations, and this decline is expected to continue. Only an estimated 2,000-2,500 adult individuals remain for the species to regenerate.

Systematics

In addition to the Hucho bleekeri , three other species belong to the genus Hucho : Hucho Hucho , Hucho ishikawae and the Taimen ( Hucho taimen ). These three species occur in Europe (Danube catchment area), Korea and Russia.

Within the salmon fish, the genus Hucho belongs to the subfamily Salmoninae and within this subfamily, together with its purely East Asian sister genus Brachymystax, it forms a systematic unit ( clade ) which is opposite to the other Salmoninae genera ( Oncorhynchus , Parahucho , Salmo , Salvelinus , Salvethymus ).

See also

supporting documents

  1. ↑ 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)
  2. ↑ a b c Froese, Rainer and Pauly, Daniel, eds. (2014). " Hucho bleekeri " in FishBase . April 2014 version.
  3. ↑ a b c Song, Z. 2012. Hucho bleekeri . In: IUCN Red List of Threatened Species 2012: e.T13151680A13151682. https://dx.doi.org/10.2305/IUCN.UK.2012.RLTS.T13151680A13151682.en . Downloaded on April 21, 2020.
  4. ↑ Hu et al. 2008. "Threatened fishes of the world: Hucho bleekeri Kimura, 1934 (Salmonidae)." Environmental Biology of Fishes 82.4: 385-386.
  5. ↑ Hucho on Fishbase.org (English)
  6. ↑ Alexis Crête-Lafrenière, Laura K. Weir, Louis Bernatchez: Framing the Salmonidae Family Phylogenetic Portrait: A More Complete Picture from Increased Taxon Sampling. PLOS ONE , 2012, 7 (10): e46662. DOI: 10.1371 / journal.pone.0046662
  7. ↑ SV Shedko, IL Miroshnichenko, GA Nemkova: Phylogeny of salmonids (Salmoniformes: Salmonidae) and its molecular dating: Analysis of mtDNA data. Russian Journal of Genetics, June 2013, Volume 49, Issue 6, Pages 623-637. DOI: 10.1134 / S1022795413060112