cle atrophy. The most common oil products, diesel
fuel, and hexachlorocyclohexane, are known to
cause anomalies in muscles of juvenile Russian
sturgeon and beluga that are similar to those seen in
sturgeons with muscle atrophy (Altufiev1994).
Accumulation of heavy metals and pesticides in
gonads, livers, and muscles was discovered recently
(Anclreevet al. 1989, Gapecva et al. 1990, Golovin et
al. 1990, Kirillov et al.1990,Moroz 1990, Paveleva et
al. 1990). Since the late 1980s, high levels of tumors,
abnormalities in gonad development and gameto-
genesis, and disturbances in the morphogenesis of
organs have been found in all three species of stur-
geons(Romanov et al. 1989, Romanov & Sheveleva
1992, Romanov & Altufev 1990). In 1990, 100% of
eggs taken from females of all three species of stur-
geons caught in the lower reaches of the Volga River
showed ahnormalities and 100% of the embryos
were nonviable (Shagaeva et al. 1993). Therefore,
the impact of pollutiononpresent populations of
sturgeons in the Volga River and Caspian Sea is very
high and its effect will intensify in the near future.
Another serious threat to survival of sturgeons in
the Caspian Sea basin is uncontrolled overfishing
and an enormously increased level of poaching. Af-
ter dissolution of the Soviet Union in1991,sea har-
vest, which had been prohibited for 30 years (since
1962) under Soviet law, began again. The absence of
common fishery agreements among the states bor-
dering the Caspian Sea (Russia, Azerbaidjan, Turk-
menistan, Kazakhstan, and Iran)^1 aggravated the al-
ready grave situation of the commercial species of
sturgeons. Political and economic instability in Rus-
sia, along with inflationary pressures in the region,
caused a sharp rise in poaching in the Volga River
during the early 1990s, concentrated at feeding and
spawning areas. Unfortunately, the unprecedented
scale of poaching in the Volga River occurred si-
multaneously with decreases in efforts to replenish
sturgeon stocks by stocking of artificially reared ju-
veniles. Together, these factors threaten the surviv-
al of commercial sturgeon species in the northern
part of the Caspian Sea basin.
(^1) On 14 November 1996. Russia, Azerbaijan, Turkinmistan, and
Iran signed an agreement to ban all sturgeon fishery in the Cas-
pian Sea in 1997. Under the apgreement, sturgeon fishery will only
be allowed in the deepest waters of the Volga and Ural rivers
(Editors’ note, February 1997).
Dynamics of the loss of Caspian Sea sturgeon fish-
eries
(1) Before Volga River flows were regulated in
1958, sturgeon stocks in the Volga-Caspian system
were supported by natural reproduction only. Be-
tween 1950–1958, returning spawning populations
consisted of about 20 000 individuals of beluga,
400 000 stellate sturgeon, and 700 000 Russian stur-
geon.
(2) From 1959 through 1972, recruitment was
mostly natural. A ban on the catch of sturgeon from
the Caspian Sea in 1962 had a positive effect on re-
turning stocks. Also, beginning in 1957, sturgeon
hatcheries began to release juveniles to maximize
the size of sturgeon populations. The number of
surgeons returning to the Volga River to spawn was
from 5700 to 11 000 beluga, from 600 000 to 907 000
stellate sturgeon, and from 334 000 to 450 000 Rus-
sian sturgeon. All three commercial species were
cut off from their historic spawning areas by con-
struction of dams in 1958–1960, and the length of the
migration path was reduced. This initiated a gradu-
al decrease in natural reproduction so that by the
1970s the beluga stock was consisted primarily of
hatchery propagated fish.
(3) The period of 1973 through 1977 saw a sharp
reduction in natural reproduction, a worsening en-
vironmental situation caused by a drop in the sea
level which increased water salinity, decreased the
area of feeding grounds, and reduced the deltaic ar-
ca where juveniles overwinter. This period was par-
ticularly critical for the survival of juveniles of all
three species, especially for the Russian sturgeon,
and many eggs laid on spawning grounds did not de-
velop.
(4) From 1978 through 1989, environmental con-
ditions changed. Water levels rose in the Caspian
Sea and salinity decreased. The number of juveniles
released in the delta of the Volga River increased to
19 million beluga juveniles, 18 million stellate stur-
geon. and 45.7 million Russian sturgeon. But, be-
ginning in 1985, high levels of water pollution began
to affect sturgeons, and their natural reproduction
decreased sharply. The recruitment of individuals
from these generations have not been estimated yet
since these fish are still too young to be caught.