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The Ponto-Caspian invasive gobiid fish Proterorhinus marmoratus (tubenose goby) is recorded for the first time from the Baltic Sea area: single specimens were found in the Neva River on 15 August 2006 and the eastern part of the Gulf of Finland on 23 July 2007. This fish is at the initial stage of a Baltic Sea invasion.
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Alexander E. Antsulevich (2007) studied this question.
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