Aquatic alien species in Greece (2009): tracking sources, patterns and effects on the ecosystem.

Abstract

More than 270 Aquatic Alien Species (AAS) are reported from Greece. Besides the introductions via the Suez Canal, the most important vectors of introduction are imports for aquaculture purposes and trade. Most marine biota has spread in the south Aegean, while freshwater biota occur mostly in northern Greece. Prime source regions are the Indo-Pacific and America. For all source regions and taxonomic groups considered, the invasion rate has been increasing since the end of the last century, a trend indirectly related to the “tropicalization” of the Mediterranean Sea. Although the impact of AAS has been poorly documented, a literature review reveals many cases of formerly considered tropical species (such as the ciguatera causing genus Gambierdiscus) in the Mediterranean Sea and specifically in Greek waters, the presence of which might not only affect the ecosystems, but also human health and economic activities, such as fisheries, aquaculture and tourism. International as well as EU regulations are implemented in theory but not adequately enforced or need to be updated based on recent advances of AAS. A targeted public awareness campaign aimed particularly at resource users and site-based monitoring is suggested.