Environmental Biology of Fishes 48:373–380,1997.
© 1997 Kluwer Academic Publishers. Printed in the Netherlands.
Sturgeons and the Aral Sea ecological catastrophe
Iliya Zholdasova
Institute of Bioecology, Karakalpak Branch of the Academy of Sciences of Uzbekistan, Nukus, Republic Kara-
kalpakstan
Received 5.4.1995 Accepted 16.3.1996
Key words:Amu-Dar River, Syr-Dar River,Pseudoscaphirhynchus kaufmanni,P.fedtschenkoi,P.hermanni,
Acipenser nudiventris, pollution, acclimatization, Nitzschia
SynopsisA shortdescription of thecatastrophicchanges in theecology of theAral Seabasinduring thethreelast
decades is presented. Thesechanges have influenced thestatus of twoacipenserid endemics to thearea, the
large Amu-Dar shovelnose,Pseudoscaphirhynchuskaufmanni,and the shipsturgeon,Acipensernudiventris.
The mainbiologicalcharacteristics ofbothspecies in the newenvironmentalconditions aregiven.Previous
unsuccessfulattempts to introduce otheracipenseridspeciesinto thearea arealsodescribed.International
cooperation isneeded forsaving thelast surviving speciesrepresenting thegenusPseudoscaphirhynchus.The
only twootherspecies ofthe samegenus,P. fedtschenkoiandP. hermanni,havealready becomevictims of the
Aral Seacatastrophe and are apparentlyextinct.Introduction 1993). Twosturgeonspecies, the Syr-Dar and small
Amu-Dar shovelnose sturgeons,were among the
Historically theendemic fauna of theAral Sea ba- firstvictims ofthis disasterand seem tobe extinct.
sin included fouracipenserid species: thelarge The Syr-Dar shovelnosesturgeon was aregional en-
Amu-Dar shovelnosesturgeon,Pseudoscaphirhyn- demic andoccurred in the SyrDaryaRiverbasin
chuskaufmanni(Bogdanov,1874), small Amu-Dar only(Berg1948). Thelastreport onthissturgeon in
shovelnosesturgeon, P.hermanni (Kessler,1877), Kazakhstanrefers to1952–1953 (Dairbaev1959,
Syr-Dar shovelnose sturgeon, P. fedtschenkoi Mitrofanov et al.1986). Thesmall Amu-Dar shov-
(Kessler,1872), andshipsturgeon,Acipensernudi- elnose sturgeon was aregionalendemic of the Amu
ventris(Lovetsky,1828)(Nikolskii 1938,1940,Berg DaryaRiver, andinitially it wasdescribed as arare
1948,Tleuov &Sagitov1973,Tleuov & Tleuberg- species (Nikolskii1938,Berg1948). It has notbeen
nov 1974). Allshovelnose sturgeons are freshwater foundsince1982. It isbelievedthatthisspecies has
species, while theshipsturgeon is an anadromous disappearedcompletely(Pavlov et al.1985)^1 .De-
fish. scription of thecontemporary status of the two re-
During thelast 30years, theenvironmental con- mainingendemicspecies,Pseudoscaphirhynchus
ditions in this region changeddrasticallybecause of kaufmanniandAcipenser nudiventris, in the con-
the drying of theAralSea and extremepollution
(Aladin & Potts1992); thewhole change isknown
now as the Aral Seaenvironmentaldisaster or ca-
tastrophe (Feshbach &Friendly 1992,Peterson(^1) In April 1996 threeP. hermanniwere coughtnear thetown of
Kerki(Salnikov et al. 1996).