The Amu Darya sturgeon or false shovelnose sturgeon (''Pseudoscaphirhynchus kaufmanni'') is a
critically endangered species of fish in 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 ...
Acipenseridae
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early ...
. It is found in
Turkmenistan
Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the sout ...
,
Uzbekistan
Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...
,
Tajikistan
Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...
and perhaps
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
.
It inhabits quite shallow flowing waters that are turbid and muddy.
[Birstein, V.J.; J.R. Waldman; and W.E. Bemis, editors (1997). Sturgeon biodiversity and conservation, pp. 377–378, 381–382. Kluwer Academic Publishing. ]
Appearance
![Pseudoscaphirhynchus kaufmanni 1996 stamp of Kyrgyzstan](https://upload.wikimedia.org/wikipedia/commons/0/0a/Pseudoscaphirhynchus_kaufmanni_1996_stamp_of_Kyrgyzstan.jpg)
The Amu Darya sturgeon is a small sturgeon, but the largest species of ''
Pseudoscaphirhynchus
''Pseudoscaphirhynchus'' is a genus of relatively small, highly threatened sturgeons that are restricted to the Aral Sea system (although extirpated from the Aral Sea itself), including the Amu Darya and Syr Darya river basins, in Central Asia.
...
'', reaching up to in weight and in total length, excluding tail filament.
It has a long, thin tail filament. For example, two individuals that both had a length of about excluding tail filament were and including tail filament.[ The species occurs in two morphs: a relatively large, light-coloured and late maturing morph, and a small, dark-coloured and early maturing morph. The small morph is roughly of similar size to '' P. hermanni'', a species that lacks a tail filament.][
]
Behavior
The Amu Darya sturgeon feeds on small fish and aquatic insect larvae, with large individuals being mostly 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 ...
.[
Studies in the 1960s and 1970s showed that Amu Darya sturgeon reach maturity when 5–8 years old (slightly later in females than males), but in the 1990s the youngest mature individuals only were 4 years old, possibly due to environmental changes in their habitat.][ The breeding season is from March to May when the water is .][ During a season, a female of the large morph lays about 3,100–36,500 eggs and a female of the small morph about 1,000–2,000 eggs, but it is possible that they only do this every 4–5-year.][ The species can reach an age of more than 14 years.] Historically, it was known to hybridize
Hybridization (or hybridisation) may refer to:
*Hybridization (biology), the process of combining different varieties of organisms to create a hybrid
*Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals
*Nu ...
with ''P. hermanni'', with the offspring having features that are intermediate between the two species.[
]
Conservation status
The Amu Darya sturgeon once occurred throughout the Amu Darya
The Amu Darya, tk, Amyderýa/ uz, Amudaryo// tg, Амударё, Amudaryo ps, , tr, Ceyhun / Amu Derya grc, Ὦξος, Ôxos (also called the Amu, Amo River and historically known by its Latin language, Latin name or Greek ) is a major rive ...
river basin, including its delta in the Aral Sea
The Aral Sea ( ; kk, Арал теңізі, Aral teñızı; uz, Орол денгизи, Orol dengizi; kaa, Арал теңизи, Aral teńizi; russian: Аральское море, Aral'skoye more) was an endorheic basin, endorheic lake lyi ...
, today it is found in the middle Amu Darya River (between Kerki
Kerki is a city in and capital of Kerki District, Lebap Province, Turkmenistan. It was formerly known as Zamm and, between 1999 and 2017, as Atamyrat.
Geography
It is situated on a plain on the left bank of the Amu Darya river. Nearby towns a ...
and Chardzhou (modern name is Turkmenabad) in Turkmenistan and also lower in Kyzylrabat area (Uzbekistan), also in more lower Amu Darya River (between Pitnak and Urganch in Khorezm province, Uzbekistan) and in the lower Vakhsh River
The Vakhsh (Russian and Tajik: Вахш - ''Vaxsh'', fa, وخش), also known as the Surkhob (Сурхоб, سرخاب), in north-central Tajikistan, and the Kyzyl-Suu ( ky, Кызыл-Суу), in Kyrgyzstan, is a Central Asian river, and one of ...
(an Amu Darya tributary) in Tadjikistan. It has declined because of habitat loss, pollution and poaching, and is rated as critically endangered by 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 ...
. Despite its threatened status, strong decline and range contraction, it can be locally fairly common and overall it is the least rare species of ''Pseudoscaphirhynchus'' ('' P. fedtschenkoi'' is possibly extinct and ''P. hermanni'' only survives in very small numbers).[Salnikov, V.B.; V.J. Birstein; and R.L. Mayden (1996). The contemporary status of the two Amu Darya River shovelnose sturgeons, Pseudoscaphirhynchus kaufmanni and P. hermanni. The Sturgeon Quarterly 4(3): 10–14.]
In general the status of the Amu Darya sturgeon is poorly known and further surveys are necessary. A part of its range is in the Amudarya State Nature Reserve
Amyderýa Nature Reserve is a nature reserve (''zapovednik'') of north-eastern Turkmenistan.
Established in 1982 to protect part of the Amu Darya River, it is located in the north-east of Lebap Province
Lebap Region ( tk, Lebap welaýaty/Л ...
. Although the Amu Darya sturgeon is a fully protected species throughout its range,[Mikodina, E.; and A. Novosadova (2015). Rare Acipenserids in Russian Aquaculture. ВОПРОСЫ РЫБНОГО ХОЗЯЙСТВА БЕЛАРУСИ 31: 38–51.] 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 ...
is widespread and fisheries management in the region is very poor.[UNEP-WCMC. (2013). UNEP-WCMC, Cambridge.] The species has been listed on CITES Appendix II
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
since 1998. This restricts international trade in the species, but two were legally exported from Uzbekistan to Russia for zoological purposes in 2002–2012, and in 2013 Uzbekistan set the export quota to twenty individuals.[
Many sturgeon species have been bred in captivity and this often forms the basis for restocking the wild populations.][ In the 1980s there were attempts of doing this with the Amu Darya sturgeon. Although some progress was made, captive breeding ultimately failed because the embryos died.][ Since 2010, Eurasian Regional Association of Zoos and Aquariums (EARAZA) together with various Russian and Uzbekistan institutes as well as officials of Tajikistan) has attempted to start a breeding program for the Amu Darya sturgeon, but as of 2021 it has not succeeded (in 2020 Khorezm Mamun Academy in Khiva (Khorezm province branch of Academy of Sciences of Uzbekistan) - the main partner in the program) has temporary stopped shovelnose conservation project because of lack of financial support) although some progress was made (the eggs were incubated in the field in 2012 but the embryos died).][
]
Taxonomy
The karyotype
A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
of the Amu Darya sturgeon consists of roughly 118–120 chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s; it is classified as a low-chromosome group acipenserid fish. Studies of its genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
and karyotype show clear differences compared to the shovelnose sturgeon
The shovelnose sturgeon (''Scaphirhynchus platorynchus'') is the smallest species of freshwater sturgeon native to North America. It is often called "hackleback", "sand sturgeon", or "switchtail". Switchtail refers to the long filament found on ...
(''Scaphirhynchus platorhynchus''), indicating that the usually recognized subfamily Scaphirhynchinae
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early ...
is polyphyletic
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...
. Further karyological research on the Amu Darya sturgeon may help in determining polyploid
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...
evolution in acipenserid fish.
References
External Links
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) digital morphology
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) at FishBase
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) in the lower Amu Darya River (Uzbekistan)
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) in the lower Vakhsh River (an Amu Darya tributary) in Tadjikistan
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) in the middle Amu Darya River (Uzbekistan)
Large Amu Darya Shovelnose Sturgeon (Pseudoscaphirhynchus kaufmanni) in the middle Amu Darya River (Turkmenistan)
* V.B. Sal’nikov, N.V. Akimova, G.I. Ruban, R.L. Mayden, B.R. Kuhajda. Reproductive System of Amu-Dar Shovelnoses - Big Shovelnose Pseudoscaphirhynchus kaufmanni and Little Shovelnose P. hermanni (Acipenseridae). Journal of Ichthyology, Vol. 43, No. 7, 2003, pp. 516–527. Translated from Voprosy Ikhtiologii, Vol. 43, No. 4, 2003, pp. 499–510: http://life-on-earth.ru/images/Salnikov-Amudarya_Shovelnose_Reproductive_System.pdf
* V.B. Sal’nikov, R.L. Mayden, B.R. Kuhajda. Tagging of the Big Amu-Dar Shovelnose Pseudoscaphirhynchus kaufmanni (Acipenseridae). Journal of Ichthyology, Vol. 44, No. 9, 2004, pp. 778–782. Translated from Voprosy Ikhtiologii, Vol. 44, No. 6, 2004, pp. 832–836: http://life-on-earth.ru/images/Salnikov-Amudarya_Shovelnose_Tagging.PDF
* Bernard R. Kuhajda (University of Alabama, USA), Richard L. Mayden (St.Louis University, USA), Vladimir. B. Sal’nikov (National Institute of Deserts, Flora and Fauna, Turkmenistan). Evolutionary and Conservation Studies of Imperiled Sturgeon Species of the Genus Pseudoscaphirhynchus in Central Asia. Report, 2007. Copyright 2016, All Rights Reserved: http://life-on-earth.ru/images/Lopatonosy-Turkmenistan/Salnikov-Amudarya_Shovelnose_Sturgeon_Eng.pdf
* C. B. Dillman, R. M. Wood, B. R. Kuhajda, J. M. Ray, V. B. Salnikov, R. L. Mayden. Molecular systematics of Scaphirhynchinae: an assessment of North American and Central Asian Freshwater Sturgeon Species. Journal of Applied Ichthyology, 23 (2007), pp. 290–296: http://life-on-earth.ru/images/Lopatonosy-Turkmenistan/Molecular_systematics_of_Scaphirhynchinae.pdf
{{Taxonbar, from=Q1507886
Pseudoscaphirhynchus
Freshwater fish of Asia
Fish of Central Asia
Fauna of Tajikistan
Critically endangered fish
Critically endangered fauna of Asia
Taxonomy articles created by Polbot
Fish described in 1877