Range Expansion of the Zebra Mussel Invasion (Dreissena polymorpha) (Mollusca, Bivalvia) in Western Siberia: Veligers in the Plankton of the Pyshma River (Tyumen Region)

The first data on the distribution and quantity of Dreissena polymorpha veligers in the plankton of the lower reaches of the Pyshma River (Western Siberia) are presented. Veligers were found throughout the surveyed section of the watercourse, right up to the mouth of the Pyshma River. The seasonal dynamics of the population of this introduced species were revealed.