Additional new records of Caulerpa cylindracea Sonder 1845 along the West Algerian Coasts

Since considered as invasive species, Caulerpa cylindracea Sonder 1845 has been the subject of numerous prospectingworks aiming its localisation and identification along the western Mediterranean Coasts. In this study, we provide newoccurrence of the introduced seaweed Caulerpa cylindracea in the West Algerian coasts. C. cylindracea has been reportedfor the first time in Canastel and Zimba (West Algerian coasts) at different density distribution levels. The colonisation levelwas estimated to Level (I) for Zimba, Canastel and Marsat El Hadjaj sites, which indicated a beginning of spreading. Bycontrast, in Cap Carbon a Level (II) was recorded suggesting an advanced colonisation of the invasive taxon. Macroalgaeand seagrass assemblage characterisation showed low cover for all species in the invasion zone. Accordingly, Caulerpacylindracea is more present in Cap Carbon than in Zimba, Canastel and Marsat El Hadjaj. Considering the observedabundance of macroalgae and seagrasses, Caulerpa prolifera seemed to resist the invasion of C. cylindracea in Marsat ElHadjaj.