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As to the information concerning the presence of
Siberian sturgeon (Acipenser baerii) caviar in the caviar of Russian
sturgeon (Acipenser gueldenstaedtii) supplied to the USA from
Astrakhan, we can report that:
 The description of
sturgeon species was completed by the late 19th century by
outstanding scientists of that time (Berg, 1904). During the 20th
century, this problem was repeatedly examined by experts on the basis not
only of morphometric characteristics and peculiarities of biology, but also
using updated methods (biochemical, genetic). This allowed rather an
objective classification and identification of species of the genus Acipenser.
Specifically, the independence of the species A. barii and A.
gueldenstaedtii is beyond doubt. In addition, the phylogenetic
relationship was revealed between Siberian, Persian and Russian sturgeons
(Birstein, De Salle, 1998; Sokolov, Vasiliev, 1989) which was associated
with common ancestors that migrated into the Ponto-Caspian basin from
Siberian rivers through the system of water bodies during the period of
maximum freezing (Berg, 1928, 1949). Common phylogenetic ancestry gave rise
to the affinity of genetic features of these fish species.
The results of studies of antigenic composition of serum proteins,
fractional composition of hemoglobin and blood serum proteins, isoelectric
focusing of hemoglobin, isoenzymic composition of muscular malate
dehydrogenase and other biochemical characteristics show clear specific
distinctions between Russian, Persian and Siberian sturgeons. At the same
time, these data make it possible to regard Russian and Siberian sturgeons
as the most affinitive species representing a common phyletic line (Bal,
Karnaukhov, Geraskin, 1981; Vasiliev, 1999; Geraskin, 1979; Lukyanenko,
Umerov, Altufiev, 1970; Perevaryukha, 2001).
The Russian sturgeon in the Caspian Sea has rather a complicated
intraspecific composition. First of all, it should be noted that there are
Russian sturgeon populations which display homing to certain spawning
rivers. The largest of them are Volga, Ural and Kura populations. The Volga
River population is the most abundant. There are also small populations
spawning in the rivers Terek, Sulak, Samur and Sefidrud. The largest
populations are divided into two seasonal races spring and winter that
differ in the time of entering rivers and spawning seasons. The spawning
population of Russian sturgeon is also divided into biological groups that
are different in reproductive biology. I.A. Barannikova (1957) gave a
description of four biological groups of the Volga River population of
Russian sturgeon depending on the rate of gonad maturation and time of
spawning: early and late spring, winter forms of summer and autumn run.
Three biological groups (early and late spring, winter) were revealed in
the Ural River population of Russian sturgeon (Gerbilsky, 1957).
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