Non-indigenous species in Mediterranean ports: a knowledge baseline

Port areas have been considered bioinvasion hotspots due to the concentration of several invasion vectors. However, the actual distribution of non-indigenous species (NIS) in Mediterranean ports is still poorly understood. Here we conducted a literature review with the aim to provide a knowledge baseline about NIS distribution in Mediterranean ports. NIS distribution in Mediterranean ports showed a high degree of heterogeneity in terms of studies across the whole basin, with a limited knowledge on both specific taxa and geographical areas, as well as a generally low proportion of investigated ports. The low rate of specific studies designed to monitor these particular environments may represent the main source of knowledge gaps. Mediterranean ports host NIS from all regions of the world, playing a key role in marine bioglobalization. Our synthesis represents the first baseline addressing the presence of NIS in Mediterranean ports, which may be useful to define plans of NIS management and strategies focusing on a network of recognised focal hotspots.