Species Invading the Baltic Sea

It is unknown for several species that how they were introduced into the Baltic Sea, although shipping is assumed to be the most dominating vector of species introduction, followed by aquaculture activities. In order to explain why so many species invaded the Baltic Sea, following arguments come into consideration  

TABLE 16.2 Species Introduced in the Baltic Sea (after Streftaris et al. (2005), Olenin et al. (2006) and Own Data 

together with commercial species AQ, aquarium species R, reason unknown SH, international shipping B, Beltsee Bo, Gulf of Bothnia C, Central Baltic Sea K, Kattegat OL, Oder Lagoon +, established —, not yet established. 

Brackish water species have broader physiological characteristics, which means a 

Brackish waters have the poorest species richness compared to similar euhaline 

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