Hunting Marine Invaders with Autonomous Reef Monitoring Structures (ARMS)

The North Adriatic Sea is one of the most bio-invaded areas of the Mediterranean, primarily due to its semi-enclosed nature and the presence of intense aquaculture activities and of major ports. Effective management of marine bioinvasions requires accurate assessment and monitoring of Non- Indigenous Species (NIS) using standardized, integrative, and innovative approaches. In this study, we used Autonomous Reef Monitoring Structures (ARMS) to monitor the spatial and temporal changes in NIS communities across the North Adriatic Sea from 2021 to 2023. ARMS were deployed in different sites on the Italian and Slovenian coasts with varying levels of human disturbance. By comparing data from morphological identification, photo analysis and cytochrome c oxidase subunit I (COI) and 18S rRNA amplicon sequencing, we detected at least 18 NIS taxa. Furthermore, we analyzed the changes in NIS communities in ARMS over time and across different locations. The results highlight the potential of an integrative taxonomic approach for monitoring bioinvasions. However, our findings underscore the importance of harmonized protocols for ARMS deployment timing and data processing, which can be achieved only through international cooperation and long- term monitoring programs.