Non-indigenous seaweeds in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia: a critical synthesis of diversity, spatial and temporal patterns

• Published in: European Journal of Phycology
• Main Authors: van der Loos, Luna, Bafort, Quinten, Bosch, Samuel, Ballesteros, Enric, Bárbara, Ignacio, Berecibar, Estibaliz, Blanfuné, Aurélie, Bogaert, Kenny, Bouckenooghe, Silke, Boudouresque, Charles-François, Brodie, Juliet, Cecere, Ester, Díaz-Tapia, Pilar, Engelen, Aschwin, Gunnarson, Karl, Shabaka, Soha Hamdy, Hoffman, Razy, Husa, Vivian, Israel, Álvaro, Karremans, Mart, Knoop, Jessica, Le Gall, Line, Maggs, Christine, Mineur, Frédéric, Parente, Manuela, Perk, Frank, Petrocelli, Antonella, Rodríguez-Prieto, Conxi, Ruitton, Sandrine, Sansón, Marta, Serrão, Ester, Sfriso, Adriano, Sjøtun, Kjersti, Stiger-Pouvreau, Valérie, Surget, Gwladys, Taşkin, Ergün, Thibaut, Thierry, Tsiamis, Konstantinos, van de Weghe, Lotte, Verlaque, Marc, Viard, Frédérique, Vranken, Sofie, Leliaert, Frederik, de Clerck, Olivier
• Other Authors: Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDV]Life Sciences [q-bio]; Northeast Atlantic
• Online Access: https://hal.univ-brest.fr/hal-04373042; https://hal.univ-brest.fr/hal-04373042/document; https://hal.univ-brest.fr/hal-04373042/file/107351.pdf; https://doi.org/10.1080/09670262.2023.2256828

International audience Effective monitoring of non-indigenous seaweeds and combatting their effects relies on a solid confirmation of the non-indigenous status of the respective species. We critically analysed the status of presumed non-indigenous seaweed species reported from the Mediterranean Sea, the Northeast Atlantic Ocean and Macaronesia, resulting in a list of 140 species whose non-indigenous nature is undisputed. For an additional 87 species it is unclear if they are native or non-indigenous (cryptogenic species) or their identity requires confirmation (data deficient species). We discuss the factors underlying both taxonomic and biogeographic uncertainties and outline recommendations to reduce uncertainty about the non-indigenous status of seaweeds. Our dataset consisted of over 19,000 distribution records, half of which can be attributed to only five species (Sargassum muticum, Bonnemaisonia hamifera, Asparagopsis armata, Caulerpa cylindracea and Colpomenia peregrina), while 56 species (40%) are recorded no more than once or twice. In addition, our analyses revealed considerable variation in the diversity of non-indigenous species between the geographic regions. The Eastern Mediterranean Sea is home to the largest fraction of non-indigenous seaweed species, the majority of which have a Red Sea or Indo-Pacific origin and have entered the Mediterranean Sea mostly via the Suez Canal. Non-indigenous seaweeds with native ranges situated in the Northwest Pacific make up a large fraction of the total in the Western Mediterranean Sea, Lusitania and Northern Europe, followed by non-indigenous species with a presumed Australasian origin. Uncertainty remains, however, regarding the native range of a substantial fraction of non-indigenous seaweeds in the study area. In so far as analyses of first detections can serve as a proxy for the introduction rate of non-indigenous seaweeds, these do not reveal a decrease in the introduction rate, indicating that the current measures and policies are insufficient to battle ...