Fish book son indd

Sturgeons – contemporaries of dinosaurs
141
of a mouse or snake (hence the local name of this fi sh, which means mouse- 
or snake-tail.) It was the Ural Cossacks who resett led to the Amu Darya in the 
late XIX century who started catching shovelnose sturgeons. In terms of its 
taste their meat resembles that of a sterlet.
As with other shovelnose sturgeons, these sturgeons are typically 
fl uvial  fi sh that inhabit the coastal areas of the main channel on sand/
gravel shallows or hard argillaceous bott om, oft en among the islands in 
the middle of the river. Their large lower mouth that protrudes in the form 
of a tube enables them to suck in small water invertebrates, like larvae and 
pupae of chironomids, trichopterans and mayfl ies, from the soil. The large 
shovelnose sturgeons also feed on small fi sh species such as the young 
of barb, razorfi sh, loach, ostroluchka (Capoetabrama kuschakewitsch). Their 
favorite food is the roe of other fi sh species. The have two environmental 
forms: large and small. The large form att ains sexual maturity at the age of 
6-7 and body length of over 40 cm; the small, stunted form att ains maturity 
at the same age but with a length of 23-30 cm. These two forms also diff er 
in fertility: the large form may lay between 10,000 and 15,000 eggs, while 
the small lays 1,000 to 2,000 eggs. The males usually reach maturity a year 
before females. 
The shovelnose sturgeons spawn on coarse-grain sand shallows and over 
scatt ered rocks in the river mouth in the fast stream. Spawning takes place 
in early spring between late March and April at a water temperature of 10-14 
deg C. The roe is of a bott om type and adhesive, with a diameter of 1.5 to 2.7 
mm. The sex ratio at the spawning grounds is 1:1.
The range of the shovelnose sturgeons has reduced and their abundance 
has fallen dramatically due to the construction of irrigation facilities that 
has caused irreparable damage to the natural reproduction of these fi sh. 
Many young individuals also die in the irrigation channels which they enter 
through water-intake facilities. Poaching has also caused a not inconsiderable 
amount of harm. 
In recent years att empts have been made to keep and breed large shovelnose 
sturgeons in artifi cial conditions. The fi sh lived at the Moscow Zoo in special 
aquariums with a circular fl ow of water. They fed eagerly on bloodworms, 
earthworms, minced meat and fi sh and squid. Using hypophysial injections, 
the scientists managed to make the fi sh att ain sexual maturity in experimental 
conditions and succeeded in obtaining fertilized eggs from them. These eggs 
were incubated for 77 hours at a water temperature of 20 deg C but all the 
hatched fries died due to technical problems. This experiment in keeping 

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G.M.Palatnikov,  R.U.Qasimov
142
shovelnose sturgeons in captivity showed that these fi sh are extremely 
sensitive to a change in the water chemistry and to pollution. One of the main 
reasons why their abundance has decreased so dramatically may be that they 
were poisoned as a result of the large amount of chemical products associated 
with cott on growing (fertilizers, herbicides etc.) which are discharged into 
water bodies. Developing sturgeon farming technology is an exceptionally 
topical issue, as this is, essentially, the only way to save these wonderful fi sh. 
Measures to prevent their gett ing into water intakes need to be signifi cantly 
stepped up, by installing fi sh protection structures at the intake of irrigation 
systems and at pumping stations. The river areas where these sturgeons are 
still preserved must be put under special protection.
Small Amu-darya shovelnose sturgeon (Pseudoscaphirhynchus hermanni 
Kessler, 1877) – inhabits the Amu Darya River.
Small Amu-darya false shovelnose sturgeon
(Pseudoscaphirhynchus hermanni)
Critically endangered species (category I).
It was fi rst described in 1876 by Academician A.N. Severtsov. The small 
shovelnose sturgeon is much rarer than the large. They reach a length of 
27 cm. They diff er from large shovelnose sturgeons by their smaller size, lack 
of tail thread and spikes on the snout; furthermore, their snout is longer and 
thinner. They also have distinctive creases on their pectoral fi ns, which act as 
a surculus to prevent the fi sh being carried away in a fast stream.
These sturgeons were widespread in the plain areas of the Amu Darya 
River system from the town of Termez to the mouth; they oft en occurred 
in the vicinity and upstream of Chardzhou. Unlike the large shovelnose 
sturgeons, they adhere to the deeper sections of the river channel where there 
are boulders, argillaceous rocks or pits.

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Sturgeons – contemporaries of dinosaurs
143
Their biology is virtually unknown. They reach a length of 20 cm and 
weight of 15 kg at the age of 5. Their spawning grounds and periods are also 
unknown. Insect larvae and fi sh roe have been found in their guts. In natural 
conditions they apparently hybridize with large shovelnose sturgeons.
The reasons why this species is critically endangered are the same as for 
large shovelnose sturgeons. We know of no instances of this sturgeon being 
caught in recent years. It is possible that they still remain in the unregulated 
parts of the Amu Darya, upstream of Chardzhou.
Syr-darya shovelnose sturgeon  (Pseudoscaphirhynchus fedtschenkoi 
Kessler, 1872) – inhabits the Syr Darya River.
Syr-darya false shovelnose sturgeon (Pseudoscaphirhynchus fedtschenkoi)
Very rare and possibly extinct species. Listed in the Red Book of the 
USSR.
This is the only sturgeon species represented in the Syr Darya. This 
sturgeon was discovered by the eminent Russian geographer and traveler 
A.P. Fedchenko in 1871. It is up to 27cm in length (without the tail thread). It 
diff ers from the small Amu-darya shovelnose sturgeon by the greater number 
of scutes on its back (15 to 20) and sides (37 to 46). In external appearance it 
is similar to the small Amu-darya shovelnose, having the same creasy shape 
on their pectoral fi ns. The snout shape varies signifi cantly. Some individuals 
have a well-developed tail thread and some have none.
These sturgeons are typically fl uvial  fi shes. They inhabited the plain 
stretches of the Syr Darya from the town of Balikchi to the mouth of the 
river. They occurred most frequently in the vicinity of Chinaz. Their favorite 
habitats are river areas with a sand bott om and fast-fl owing stream. Initially 
they were noted within the fauna of the dammed lakes in the Syr Darya River 

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