Invasion of the Ponto-Caspian Predatory Cladoceran Cornigerius maeoticus maeoticus ( Pengo , 1879) into the Baltic Sea

Abstract

The Ponto-Caspian predatory cladoceran Cornigerius maeoticus maeoticus (Pengo, 1879) (Poly- phemidae family) was first encountered in the Baltic Sea at two stations in the eastern part of the Gulf of Finland in August and September 2003. Most likely, this alien species was brought to the Baltic Sea from the Ponto- Caspian basin via the Volga-Baltic waterway with the ballast waters of ships. In the future, one can expect a rapid increase in the abundance of the newly formed population and its expansion over the Baltic Sea.