Monitoring non-indigenous species in port habitats: application of the ‘SERC protocol’ in the Gulf of La Spezia

An international standardized monitoring protocol for sessile fouling species was employed for the first time in the Mediterranean Sea. Native and non-indigenous species (NIS) composition was assessed in five ports in the Gulf of La Spezia (Ligurian Sea, Italy). Significant differences in mean NIS percentage cover was observed among ports, and the highest NIS cover was recorded in the harbour of La Spezia.