Abstract:

Viviparus viviparus L. is the most numerous alien species of the Novosibirsk reservoir. In some parts of the reservoir V. viviparus creates settlements with a very high density. After the death of mollusks in the bottom sediments and on the banks of the reservoir, large areas of accumulation of empty shells are formed. Due to their strong structure, the shells are poorly decomposed and can serve as a generalized indicator of the state of the mollusk population over a long time. We analyzed the size and age characteristics of the V. viviparus shells in thanatocenoses of the Novosibirsk reservoir coast. Empty shells of river snails were collected on the shores of the middle (near the village of Chingis, Ordynskoye and in the Karakansky Bay) and the lower (near the village of Borovoye, Bystrovka, Leninsky and in the Berdsky Bay) parts of the Novosibirsk Reservoir in May, 24–26, 2018. Shells height and width were measured with an electronic caliper with an accuracy of 0.1 mm. Age of mollusks was determined by the marks of a winter growth stop on the shell. It is shown that in the thanatocenoses of the middle part and in the bays of the reservoir, shells of young mollusks (the second and third years of life) prevailed. In the lower part of the reservoir, the coastal thanatocoenosis contained larger shells of adult mollusks (fourth and fifth years of life). In general, the most of V. viviparus individuals in the Novosibirsk reservoir die before they reach the age limit. It is suggested that the premature death of most river snails can be caused by significant seasonal fluctuations in the water level of the reservoir, during which the littoral is drained. Key words: Invasion; River basin of the Ob; Mollusk; Shells; Thanatocenoses References Andreev, N.I., Andreeva, S.I., Vinarsky, M.V., Lazutkina, E.A., Selezneva, M.V. (2008). Viviparus viviparus (L., 1758) (Mollusca: Gastropoda) is a New Species of Fauna of Novosibirsk Reservoir. Transactions of The International Conference on Present Status of Aquatic Bioresources. Novosibirsk, 118-120. (in Russian) Babushkin, E.S., Vinarski, M.V. (2017). First finding of the freshwater mollusk Viviparus viviparus (Linnaeus, 1758) in the River Tura (the Tyumen region). Fauna of the Urals and Siberia, 1, 19-24. (in Russian) Berezkina, G.V., Arakelova, E.S. (2010). The life-cycles and growth of some comb-branchial molluscs (Gastropoda: Pectinibranchia) in the ponds of the European part of Russia. Proceedings of the Zoological Institute RAS, 314 (1), 80-92. (in Russian). Biological Invasions in Aquatic and Land Ecosystems. (2004). Moscow, Russia: KMK Scientific Press Ltd (in Russian) Devyatkov, V.I. (2004). Invertebrates – acclimatizers of the Upper Irtysh reservoirs. Ecological problems of the agro-industrial complex: international materials. conf. Almaty, 83–86. (in Russian) Devyatkov, V.I. (2009). Macrozoobenthos. In O. P. Bazhenova (Eds.) Biocenosis successions of the Bukhtarma reservoir (95–199). Omsk, Russia: Publishing House OmASU. (in Russian) Jakubik, B. (2007). Size structure and age, mortality and fertility in Viviparus viviparus (L.). Folia Malacol, 15(3), 109–117. Karpevich, A.F. (1975). Theory and practice of acclimatization of aquatic organisms. Moscow, Russia: Pischevaya promyshlennost'. (in Russian) Kuzmenckin, D.V. (2014). Morphometric characteristic and some growth specifications of the snail Viviparus viviparus (L.) in the Novosibirsk reservoir. Altai Zoological Journal, 8, 3–9. (in Russian) Long-term dynamics of the water-ecological regime of the Novosibirsk reservoir. (2014). Novosibirsk, Russia: Publishing House of the SB RAS. (in Russian) Vinarski, M.V., Andreev, N.I., Andreeva, S.I., Kazantsev, I.E., Karimov, A.V., Lazutkina, E.A. (2015). Alien mollusk species in the aquatic ecosystems of Western Siberia: A review. Russian Journal of Biological Invasions, 6, 2–19. https://doi.org/10.1134/S2075111715030078 Vizer, A.M. (2011). Zoobenthos of the drainage zone of Novosibirsk Reservoir. Contemporary Problems of Ecology, 4, 50–55. https://doi.org/10.1134/S1995425511010085 Yanygina, L.V., Vizer, A.M. (2018). Peculiarities of invasion of Viviparus viviparus (Gastropoda, Viviparidae) into the Novosibirsk reservoir. Ecological, industrial, energy safety, Sevastopol, 1311–1313. (in Russian) Yanygina, L.V. (2019). Community-level effects of a Viviparus viviparus L. (Gastropoda, Viviparidae) invasion in the Novosibirsk reservoir. Limnology. https://doi.org/10.1007/s10201-019-00580-4 Yanygina, L.V. (2017). Pathways of macroinvertebrate invasions in the river Ob basin (West Siberia). Limnology, 18, 243–249. https://doi.org/10.1007/s10201-016-0511-x

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