Seek in ports and you shall find them: Monitoring marine invasions over time using combined standard assessment methods

Abstract

Marine biological invasions pose a significant threat to biodiversity. Port areas are sites of major interest, as artificialstructures and intense maritime traffic facilitate the arrival and spread of non-native species. Ports act ashotspots for invasions and as stepping-stones for the secondary spread of species into surrounding natural habitats.In this study, we aimed to identify and quantify marine non-native and cryptogenic invertebrate andmacroalgae species in the two main Patagonian ports, Puerto Madryn and San Antonio Este, using standardized,replicable assessment methods and comparing communities over time. We conducted field surveys combiningtwo methods previously applied in these ports (fouling samples and recruitment panels) and incorporated sedimentsampling to monitor the infaunal benthic invertebrate community. We detected 30 non-native and 7 cryptogenicspecies, including 15 new records, and others whose status shifted from cryptogenic to non-native basedon updated regional revisions. Overall, non-native species richness tripled in Puerto Madryn over eleven years.Few non-native species were shared between ports, suggesting port-specific species pools. Regardless of the port,nearly half of the identified species in this study are non-natives, underscoring the current magnitude of marineinvasions in Patagonian ports. Our findings highlight the value of using complementary methods to enhance detection,as some species were recorded by only one approach. Finally, persistent taxonomic challenges, especiallyin groups like polychaetes and sponges, underscore the need to strengthen taxonomic capacity to improve earlydetection and effectively monitor temporal and spatial changes in port communities, which is essential for understandingand managing marine invasions.