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 prospecting works aiming its localisation and identification along the western Mediterranean Coasts. In this study, we provide new occurrence of the introduced seaweed Caulerpa cylindracea in the West Algerian coasts. C. cylindracea has been reported for the first time in Canastel and Zimba (West Algerian coasts) at different density distribution levels. The colonisation level was estimated to Level (I) for Zimba, Canastel and Marsat El Hadjaj sites, which indicated a beginning of spreading. By contrast, in Cap Carbon a Level (II) was recorded suggesting an advanced colonisation of the invasive taxon. Macroalgae and seagrass assemblage characterisation showed low cover for all species in the invasion zone. Accordingly, Caulerpa cylindracea is more present in Cap Carbon than in Zimba, Canastel and Marsat El Hadjaj. Considering the observed abundance of macroalgae and seagrasses, Caulerpa prolifera seemed to resist the invasion of C. cylindracea in Marsat El Hadjaj