LAUSR

Abstract In the last decades, there has been an increase of macroalgal species appearing in new geographic regions. These new records are being linked to non-intentional global human-mediated transport. In Iceland three macroalgae species have been reported as non-indigenous. We updated the number of non-indigenous macroalgae to 8 species, 4 of which are potentially invasive. Pathways and vectors of each macroalga introduction are identified. The red algae group does not stand out in Iceland as in the nearest territories. The number of non-indigenous macroalgae will probably increase in the near future due to (1) secondary spread of species via shipping vector; (2) the growing trend of aquaculture in Norway, where surface currents will probably allow the spread of algae to Iceland; and (3) the increase of studies focusing on this matter. To address the problem, we suggest that local monitoring and mitigation programmes should be implemented across Iceland, and that regulatory and preventive measures for the maritime traffic vector should be developed.