The present paper reports the first finding of two gastropod species, Aporrhais pespelecani and Turritella communis in the north-western part of the Black Sea more than 500 km north from the edge of their native range (the Bosphorus Strait). The possible role of different hydrological factors in a spread of the species range, their perspective influence on the local demersal community and probable vectors of dissemination are discussed.