Non-indigenous macrophytes in Central Mediterranean ports, marinas and transitional waters: Origin, vectors and pathways of dispersal

Non-indigenous species are confirmed to be among the biggest threats for marine biodiversity. Among them, non-indigenous macrophytes (NIM) are well known to have local negative effects, especially in coastal ecosystems. Since transitional waters (TWs), ports and also marinas are recognized as very vulnerable coastal ecosystems, greatly subjected to biological invasions, the present study analysed the available scientific literature on NIM in such areas in the Central Mediterranean Sea (CMED), in the period 1970-2019. The analysis underlined that 27 NIM were recorded in CMED TWs, marinas and ports. Around 37% of them (10 species) are marked as invasive, while about 11% (3 species) are considered as potentially invasive. Maricultural activities resulted the key vector of introduction, while the primary pathway of NIM dispersion is related to maritime activities. The paper also discusses why in CMED TWs, marinas and ports, currently, less NIM were detected than in similar Adriatic areas.