Russian Journal of Biological Invasions

2010, issue № 1

CONTENTS

Pseudosolenia calcar-avis (Bacillariophyta, Centrophyceae) in the Caspian sea - Karpinskiy M.G. - The diatom Pseudosolenia (Rhizosolenia) calcar-avis was introduced to the Caspian Sea in 1934. During a year it spread throughout the water area with salinity higher than 8‰ and dominated in phytoplankton community constituting 80–90% of the total biomass in the Middle and Southern Caspian Sea and 20–40% in the Northern Caspian Sea. After this introduction the role of small-celled diatom algae Rhizosolenia fragilissima and pyrrhophyte Exuviaella cordata dominated earlier, had sharply decreased. The first species was found in single instances, the biomass of the second one reduced substantially. The P. calcar-avis domination was observed until 2000 at all environmental changes connected with the sea level fluctuations. In 2000 small-celled algae, including R. fragilissima began to develop intensively and in 2001 the P. calcar-avis quantity in the total biomass reduced to 5–10% in the Middle and Southern Caspian. This happened after the comb jelly Mnemiopsis leidyi invasion, which sharply decreased the number of zooplankton phytophages that led to lessen the intensity of phytoplankton eating away. P. calcar-avis, which previously successfully competed with a native phytoplankton, thanks to that nobody feed on it because of it big sizes, had lost the advantage, and small-celled algae previously eaten away began to dominate. The grazing pressure decrease has facilitated penetration into the Caspian Sea of new phytoplankton species. In the 20^th century during 70 years only 2 species penetrated into the Caspian Sea; however, during 9 years after the comb jelly invasion at least 7 species appeared in the Caspian.

Insect invasions in the terrestrial ecosystems of the Russian Far East - Kuznetsov V.N., Storozhenko S.Yu. - The question of insect invasion in the Russian Far East is discussed. It is suggested to develop the database of the insects introduced into this region.

Distribution and morphological and biological peculiarities of alien fosh species in the basin of the river Ros' (tributary of the river Dnepr) - Kutsokon Yu.K. - From the 34 species of fish in the basin of the river Ros' found in 2001 – 2006 and 2009, 9 ones are aliens. The appearance in this basin of silver carp Hypophthalmichthys molitrix (Valenciennes, 1844), stone moroko Pseudorasbora parva (Temminck et Schlegel, 1846), Prussian carp Carassius auratus gibelio (Bloch, 1783), chinese sleeper Perccottus glenii Dybowski, 1877 is a result of deliberate and non-deliberate introductions, and the appearance of southern ninespine stickleback Pungitius platygaster (Kessler, 1859), three-spined stickleback Gasterosteus aculeatus Linnaeus, 1758, bighead goby Neogobius kessleri (Gunther, 1861), racer goby Neogobius gymnotrachelus (Kessler, 1857), round goby Neogobius melanostomus (Pallas, 1814) is a consequence of. natural range expansion from the Dnepr River. For most of this species the descriptions of morphological and biological features are given.

The data on invasion and joint living of the species-invaders in the waterbodies of Dnepr basin - Protasov A.A., Silaeva A.A. - The examples of joint invasions of two species оf Dreissena and Ponto-Caspian Polychaeta and crustaceans in some reservoirs of Dnepr and in a cooling reservoir Chernobyl NPP are considered. 22 taxa of Ponto-Caspian invertebrates were marked in benthos and periphyton of Kanevskoye and Kievskoye reservoirs and in cooling-reservoir. The history of invasion and distribution of two Dreissena species in cooling-reservoir, as well as the features of their spatial and biotopic distribution in reservoirs were considered. Information about invasions of Dreissena polymorpha Pall. to cooling pond of Khmelnitskiy NPP have been presented.

Symbiotes of some alien species of freshwater fishes and mollusks of waterbodies of the Danube and Dnepr - Yurishinets V.I. - Parasitological studies of populations of some alien species of fishes and clams in the water bodies of the Dnepr River and Danube River Basins were carried out. Some aborigine and alien simbiotic species were revealed in a structure of symbiocenosis.

Polychete Hypania invalida (Polychaeta: Ampharetidae) in Kuybyshev water reservoir: distribution, size-weight parameters - Yakovlev V.A., Yakovleva A.V. - One of three polychaete species found in the Kuybyshev Water Reservoir, Hypania invalida (Grube, 1860) has been found for the first time in the middle 1970^th and become a common benthos species by present time, despite of its small density and biomass. Most often and in relatively high density polychaete were characteristic for the depths > 5 m, in silted deposits, and in communities, formed of two, the most mass in zoobenthos dreissenid species (Dreissena polymorpha and D. bugensis). If number of polychaete depends poorly on an abundance of dreissenids in communities, the biomass is maximal in communities, average weight of a body and occurrence were maximal in communities with the dreisssenid contribution in a total biomass > 50%. The tendencies of reduction of abundance and average weight of a polychaete body for the last 10–15 years. Based on results of estimation of number and average weight seasonal dynamic and terms of polychaete reproduction were studied.