|Abundance||common (usually seen)||Ref.||Winkler, H.M., K. Skora, R. Repecka, M. Ploks, A. Neelov, L. Urho, A. Gushin and H. Jespersen, 2000|
Recorded for the first time in the Gulf of Gdansk in 1990 and soon spread along its entire shore, established a population in the Vistula Lagoon and entered the lower course of the Vistula river (Ref. 52518). Most likely entered the Gulf of Gdansk via ship ballast water (Ref. 79568). Detected in small quantities in lakes connected with the sea and in coastal zones of the Pomeranian Bay (Ref. 94072). Also Ref. 49314, 55773, 79568.