Invasion

Invasion Description

1st Record: Stockholm region/Sweden/Baltic Sea (1936, Drotz et al. 2010)

Geographic Extent

Stockholm region/Sweden/Lake Mälaren (1936, Drotz et al. 2010, sporadic captures initally, more frequent after 1990, common during population pulses); Turku/Finland/Gulf of Bothnia (2004, Ojaveer et al. 2007)