Metabarcoding approach for nonindigenous species surveillance in marine coastal waters

Highlights: • Metabarcoding was applied for the surveillance of plankton communities and NIS detection. • The results were compared to those from the conventional monitoring. • Four of five detected NIS were identified exclusively by metabarcoding. • Most of the detected NIS were benthic organisms with planktonic larval stage. • The reported taxonomic composition was consistent between two methods at a family level. Abstract: In this study, high-throughput sequencing (HTS) metabarcoding was applied for the surveillance of plankton communities within the southeastern (SE) Baltic Sea coastal zone. These results were compared with those from routine monitoring survey and morphological analyses. Four of five nonindigenous species found in the samples were identified exclusively by metabarcoding. All of them are considered as invasive in the Baltic Sea with reported impact on the ecosystem and biodiversity. This study indicates that, despite some current limitations, HTS metabarcoding can provide information on the presence of exotic species and advantageously complement conventional approaches, only requiring the same monitoring effort as before. Even in the currently immature status of HTS, this combination of HTS metabarcoding and observational records is recommended in the early detection of marine pests and delivery of the environmental status metrics of nonindigenous species