Acipenser gueldenstaedti (Brandt & Ratzeburg, 1833)

COMPILED BY: Anastasija Zaiko
CITATION OF THIS ENTRY: Zaiko A. 2005. Acipenser gueldenstaedti. In: Baltic Sea Alien Species Database. S. Olenin, E. Leppakoski and D. Daunys (eds.).
INTERNET: http://www.corpi.ku.lt/nemo/mainnemo.html

TAXONOMY

Acipenser gueldenstaedti (After Mueller 1987)

IDENTIFICATION

• Diagnosis:

Spiracle present. Snout short and blunt. Gill membranes joined to isthmus. Mouth transverse and lower lip with a split in the middle. The barbels are attached closer to the tip of snout than to the mouth and they are unfimbriated. 15-51 gill rakers, which are not fan-shaped, terminated by a single tip. D: 27-51; A: 18-33 rays. 8-18 dorsal scutes; 24-50 lateral scutes and 6-13 ventral scutes. Between the rows of scutes there are numerous bony plates. The colouration is greyish black, dirty green, or dark green dorsally. Laterally, it is usually greyish brown, and ventrally, grey or lemon. The juveniles are blue dorsally and white ventrally (Brant, Ratzeburg 1833). A. gueldenstaedtii reach 2.2-2.4 m in length and 65-115 kg in weight. In the past, specimens were known to reach an age of 48 years; life expectancy has now been reduced to 38 years due to overfishing (Vlasenko et al. 1989).

Habitat and Biology :

In the sea, the Russian sturgeon inhabits shallow waters of the continental shelf; in the rivers it remains at depths from 2 to 30 m. The larvae are found at considerable depths and in rapid currents. Besides the main diadromus form, a freshwater form that does not migrate downstream to the sea has been reported from various rivers. The Russian sturgeon is a bottom-dwelling mollusc-feeder. They also readily consume crustaceans (shrimps and crabs) fishes and polychaetes. The main food items of juveniles are crustaceans, including mysids and corophiids, and polychaetes (Berg 1948). According to the diet studies in its native region, mussels appeared to be the most important food for the Russian sturgeon (Zolotarev et al. 1996).

INTRODUCTION AND DISTRIBUTION

• First record from the Baltic Sea (year, area, reference):

Year ­ 1962
Reference - Jansson 1994

• Established:

in the entire Baltic Sea ­ No
in the area of primary introduction ­ No

• Origin of the species:

Ponto-Caspian Region

• General characteristics:

Temperature. Optimal temperatures from 10 to 20⁰C. Temperatures consistently above 29 to 30⁰C are not tolerated (Hopkins 2001).
Tolerance to pollution. High sensitivity to chlorine was noted (Hopkins 2001).
Reproduction. The great majority of the males begin to reproduce at an age of 11 to 13 years, while the equivalent age for the females is 12 to 16 years (Berg 1948). The average size of females at first spawning is 1.2 m and 9 kg and spawning occurs every 2-3 years (Hochleithner and Gessner 1999). Migration to riverine spawning grounds occurs during two periods: from early spring to late autumn, peaking in summer; and during the winter, when fish hibernate in the rivers and reproduce the following year. The spawning sites are gravel or stony beds at depths from 4 to 25 m.  Spawning at water temperatures between 8.9º C and 12º C (Berg 1948). Juveniles migrate downstream to feeding grounds (Barannikova et al. 1995).

THE ROLE IN THE BALTIC SEA ECOSYSTEM

Hybridization. There is a data on hybridization between the Russian sturgeon, Acipenser gueldenstaedtii, and the great sturgeon, Huso huso. During last 2-3 decades cultivation of this hybrid has been intensively mastered in Russian aquaculture. It may be used in ranching programs as well as in cage-rearing both in marine and fresh water due to its easy adaptability to salinity of 16-18 ppt. Such adaptation does not jeopardize genetic pollution of natural populations due to a priori supposed sterility of hybrids between the great and the Russian sturgeons (Arefjev, Nikolajev 1991).
Transfer of parasites. The complete list ofparasites found in A. gueldenstaedti includes 46 species; of these, parasitic worms are the largest group and, at the present time, there are records of 36 helminth parasite species (Sattary, Mokhayer 2005). Thus there's a certain danger of parasite transfer together with new-coming Russian sturgeon individuals.

LIKELY IMPACT ON USES/RESOURCES AND HUMAN HEALTH

Aquaculture and Fisheries . Sturgeon are highly prized fish for their meat, fresh or smoked, and roe for making caviar. The most valuable and traditional sources (90%) of sturgeon products, primarily caviar, are wild stocks (e.g. Russian sturgeon Acipenser guldenstadti) from the Caspian Sea. Small quantities (10%) of caviar are produced by other countries (China, USA, Romania, Canada). Commercial aquaculture systems for sturgeon meat and caviar are established in Italy, USA, Germany, France, Spain, and Russia. Other countries have initiated sturgeon aquaculture practices (Belgium, Denmark, Hungary, Rumania, China, Japan, Korea, Canada, Uruguay). Discrepancies exist in reports of volume for sturgeon aquaculture production, however, it is clear that domestic production for meat and caviar is rising steadily. Sturgeon are raised primarily in raceways and tanks using natural surface or underground water (16-22⁰ C). Cooler temperatures (14-16⁰ C) are required for optimum spawning, incubation, and rearing of larvae. Sturgeon aquaculture provides a reliable source of high quality meat, caviar, and other products. Farmed sturgeon can also be used for replenishment of wild stocks, and education programs. Aquaculture by private industry and public hatcheries may be major contributor for conservation of sturgeon in the wild (Chapman 2001).

REFERENCES

1. Arefjev V.A., Nikolaev A.I. 1991. Cytological analysis of the reciprocal hybrids between low- and high-chromosome acipenserids, the great sturgeon, Huso huso (L.), and the Russian sturgeon, Acipenser gueldenstaedti Brandt. Cytologia, 56: 495-502.
2. Barannikova I.A., Burtsev I.A., Vlasenko A.D. Gershanovich A.D., Markarov E.V. and Chebanov M.S. 1995. Sturgeon Fisheries in Russia. Proceedings of the Second International Symposium on Sturgeons, September 6-11, 1993. Moscow-Kostroma-Moscow. VNIRO Publications: 124-130.
3. Berg, L.S. 1948. Freshwater fishes of the U.S.S.R. and adjacent countries. Israel Program for Scientific Translations Ltd, Jerusalem. 4th edition,Vol.1.
4. Brandt J.F, J.C.T Ratzeburg 1833. Caspian Sea and its rivers, Black Sea. Medizinische Zoologie, Berlin, 2: 364pp.
5. Chapman F.A. 2001. Sturgeon aquaculture. In: Book of Abstracts, Aquaculture 2001 (World Aquaculture Society, Louisiana State University) USA: 112.
6. Jansson K. 1994. Alien Species in the Marine Environment. Introductions to the Baltic sea and the Swedish West Coast. Solna, Swedish Environmental Protection Agency: 68pp.
7. Hochleithner M. and Gessner J. 1999. The Sturgeon and Paddlefishes (Acipenseriformes) of the World: Biology and Aquaculture. AquaTech Publications, Kitzbuhl: 165pp.
8. Hopkins K. 2001. A Preliminary Study of Russian Sturgeon (Acipenser gueldenstaedti) in Hawaii – 1995 to 2001. 4th International Symposium on Sturgeon. Oskhosh, Wisconsin, July 2001 DRAFT : 1-20.
   
9. Mueller H. 1987. Fishe Europas. Beobachten und bestimmen. Neumann Verlag, Leipzig-Radebeul: 320pp.
10. Sattary M., Mokhayer B. 2005. Occurence and intensity of some parasitic worms in Acipenser gueldenstaedti, A. nudiventris and Huso huso (Chondrostei: Acipenseridae) from the sowthwest of the Caspian Sea. Turk.J.Vet.Anim.Sci., 29: 1279-1284.
11. Vlasenko A.D., Pavlov A.V., Sokolov L.I. and Vasil’ev V.P. (1989). Acipenser gueldenstaedti Brandt, 1833. In: Holcik J. (ed). The Freshwater Fishes of Europe. Vol. I/II: General Introduction of Fishes. Acipenseriformes. Wiesbaden, AULA-Verlag. In: Document Doc. 10.89; Prop. 10.65. 1997. Proposal to list all Acipenseriformes in Appendix II. Submitted by Germany and The United States of America: 295-344.
12. Zolotarev, P. N., V. A. Shlyakhov and Akselev O.I. 1996. The food supply and feeding of the Russian Sturgeon Acipenser gueldenstadti and the Starred Sturgeon Acipenser stellatus of the Northwestern part of the Black Sea under modern ecological conditions. Journal of Ichthyology, 36(4): 317-322.