Ecological risk assessment for ballast waters introductions into the Police harbour basins

The purpose of the paper has been pointing out the ballast waters donor ports which for the Police harbour are of the highest risk category as far as transmitting living alien species is concerned. The species when encountering similar environmental conditions become risk to the local species as food competitors treating the local species as food and expanding in an invasive way and spreading formerly unknown diseases to the local environment. Moreover, they become dangerous to human health as well as hinder the economy development by reducing fish resources, growing on hydro-technical constructions etc.