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Pseudoscaphirhynchus kaufmanni

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII ACIPENSERIFORMES ACIPENSERIDAE

Scientific Name: Pseudoscaphirhynchus kaufmanni
Species Authority: (Kessler, 1877)
Common Name(s):
English False Shovelnose Sturgeon, Amu Darya Shovelnose Sturgeon, Big Amu Darya Shovelnose, Amu Darya Sturgeon, Large Amu-dar Shovelnose Sturgeon, Shovelfish
French Grand Nez-Pelle de Lamou Daria
Synonym(s):
Scaphirhynchus kaufmanni Kessler, 1877

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2c ver 3.1
Year Published: 2010
Date Assessed: 2009-10-24
Assessor(s): Mugue, N.
Reviewer(s): Pourkazemi, M. & Smith, K.
Justification:
The Large Shovelnose Sturgeon is endemic to the middle reaches of the Amu Darya River. Presently, there are two populations: one in the Vakhsh River (a tributary to the Amu Darya) and the second in the middle reaches of the Amu Darya. It has been extirpated from the Aral Sea and lower Amu Darya due to water abstraction. Water pollution and poaching is also a threat to the species. The species' extent of occurrence (EOO) is estimated to be around 100,000 km².

Its generation length is estimated to be 10 years. There are no estimates of current population sizes, but in the 1970s the species was abundant and now there are only reports of single specimens. There has been a drastic decline in the species range in the past 30 years, and due to poor economic status the level of poaching in Uzbekistan and Turkmenistan is thought to be increasing. However, water quality has improved as the amount of chemicals used in agriculture has declined. Overall it is suspected that there has been a population decline of more than 80% in the past three generations (30 years). Also, the species is thought to occur in less than 500km of river (two locations based on threats of poaching and pollution).

There is a critical need to survey the species from both the Uzbekistan and Turkmenistan sides of the river, as more information is needed.
History:
1996 Endangered (Baillie and Groombridge 1996)
1996 Endangered

Geographic Range [top]

Range Description: The Large Shovelnose Sturgeon is endemic to the middle reaches of the Amu Darya River. Presently, there are two populations: one in the Vakhsh River (tributary to the Amu Darya), and the second in the middle reaches of the Amu Darya, within a region between the two towns of Kerki and Chardzhou (it is not found below Chardzhou) (Zholdasova 1997, Birstein 1997).

Historically, P. kaufmanni was distributed along the river from the upper reaches (Pyandzh River) to the delta. In the early 1990s, only a few individuals were recorded in the lower reaches of the Amu Darya River (Zholdasova 1997).
Countries:
Native:
Turkmenistan; Uzbekistan
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The major part of the Large Shovelnose Sturgeon population was located in the foothill and valley areas of the river, concentrated around the villages of Kerki-Chardzhou-Ildzhik in the upper and middle reaches of the river, where they supported a commercial fishery in the 1930s. P. kaufmanni was also numerous in the lower reaches of the Amu Darya River. In the late 1970s, Large Shovelnose Sturgeon juveniles constituted up to 26% of all young fish in the lower reaches of the Amu Darya River (Zholdasova 1997).

According to Zholdasova (1997), the Large Shovelnose Sturgeon continues to reproduce in the Amu Darya River, however the rate of reproduction of the population is very low. In 1991, only two one-year-old juveniles were collected (along with a single late embryo) in the low reaches of the river; in 1993 three similar-sized individuals were collected in the Ordybai Channel of the Amu Darya River delta and one near the town of Nukus in the Kattyagar irrigation channel. This occurrence of the species in its former habitats (lower reaches of the Amu Darya River) is probably due to a significant volume and stable downstream flow which occurred in 1993, as during the mid-1990s the mean discharge in the Amu Darya River was 3.7 times higher than during the previous decade. Also, there has been a decline in the use of pesticides and fertilizers in the region, mostly due to economic problems (Zholdasova 1997).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: According to Birstein (1997) and Zholdasova (1997) the species occurs in the shallow, muddy waters of rivers with fast flowing turbulent current, with sandy or stony-pebble substrate at a depth of 1.0–1.5 m in highly turbulent muddy water. Although it is a freshwater species, the Shovelnose Sturgeon can tolerate some salinity, as it was found in the nearmouth area of the Aral Sea. It feeds mainly on small fish, with insect larvae forming the rest of the diet. Reproduction occurs in late March to early May at a water temperature of 14-16 oC. Males become mature at 5-7 years, and females at 6-8 years. Intervals between spawning periods possibly last 4-5 years.  Historically, this species easily hybridized with the other species of Pseudoscaphirhynchus, P. hermanni.

The species generation length is estimated to be 10 years.

The size and weight of individuals in the population has declined. In the past, the maximum size was 75 cm and maximum weight was 2 kg; in 1965-1966, the average body length was 37 cm and the average weight, 241 g; in 1989-1991, length was 23.6 cm on average, and the weight 100.2 g on average (Zholdasova 1997) .

Age structure of the population has also declined. In the 1960s, the majority of individuals were between 3-6 years  (varied from 1+ to 14+) and in the late 1980s, the predominance was of young individuals (1-6 years), particularly 3-year- (36.8%) and 4-year-old individuals (41.6%). The rate of linear growth has also slowed down compared with the 1960s due to a change in diet (proportion of fish in the species diet has declined) (Zholdasova 1997).
Systems: Freshwater

Use and Trade [top]

Use and Trade: This species is fished for human consumption.

Threats [top]

Major Threat(s): In the past, the Amu Darya River entered the Aral Sea near the town of Muynak (Amu Darya River delta), but since 1982, due to dams and water extraction (primarily for irrigation), the river has not reached the sea (Birstein 1997, Zholdasova 1997). There are also high levels of water pollution recorded from the Amu Darya River due to mineral fertilizers, pesticides for cotton agriculture and the disposal of drainage waste, with the highest level of pollution in the lower reaches of the Amu Darya River, though between 1989-1990 a decrease in pesticide content in the Amu Darya water was noticed (Zholdasova 1997).

The Large Shovelnose Sturgeon occurs exclusively in fast-running turbid waters. It is thought that the low levels of water in the Amu Daryr from the middle 1970s until the late 1980s decreased the flow velocity and the size of river beds, preventing migration of Shovelnose Sturgeon from the middle to the lower reaches of the Amu Darya River (Zholdasova 1997).

Conservation Actions [top]

Conservation Actions: An aquaculture project is currently being developed (by Moscow Zoo), with the aim of stocking. Part of the species distribution is within the Amu Darya nature reserve. This species was listed on CITES Appendix II in 1998.

There is a critical need to survey the species from both the Uzbekistan and Turkmenistan sides of the river, as more information is needed.

Citation: Mugue, N. 2010. Pseudoscaphirhynchus kaufmanni. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 19 December 2014.
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