Molecular barcoding confirms the presence of exotic Asian seaweeds (Pachymeniopsis gargiuliandGrateloupia turuturu) in the Cantabrian Sea, Bay of Biscay

Abstract

BackgroundThe introduction of exotic species can have serious consequences for marine ecosystems. On the shores of the Cantabrian Sea (North of Spain) there are no routine examinations of seaweeds that combine molecular and morphological methods for early detection of exotic species making it difficult to assess in the early stages their establishment and expansion processes as a result of anthropogenic activities (e.g., shipping and/or aquaculture).MethodsIn this work we used both morphological identification and molecular barcoding (COI-5P andrbcL genes) of red algae collected in Asturias, Bay of Biscay (Gijón and Candás harbours) and from the University of Oviedo’s herbarium samples.ResultsThe results confirmed the presence of exotic Asian seaweedsPachymeniopsis gargiuliandGrateloupia turuturuYamada on Cantabrian Sea shores. Several individuals of these species were fertile and developing cystocarps when collected, underlining the risk of possible expansion or continued establishment. This study constitutes the first report of the AsianP. gargiuliin this area of the Bay of Biscay.ConclusionsHere the presence of the exotic species of the HalymenialesP. gargiuliis confirmed. We hypothesize that this species may have been established some time ago as a cryptic introduction withG. turuturuin Galician shores. The detection of these species on the shores of the Cantabrian Sea is relevant since introductions ofPachymeniopsisspecies could have been overlooked on other European coasts, probably mixed withG. turuturuandP. lanceolata. Our results confirm one new alien seaweed species that has been detected using molecular methods (COI-5P region andrbcL genes barcoding) on North Atlantic shores: the Asian nativeP. gargiuli. This demonstrates that routine screening for early detection of exotic algae in the Cantabrian Sea can be used for risk assessment. Genetic barcoding should be done using bothrbcL gene and COI-5P regions since, although COI-databases are still poorer in sequences and this inhibits successful outcomes inGrateloupia-related species identifications, it is nonetheless a useful marker for species-level identifications in seaweeds.