Biodiversity and conservation of Cnidarians along the Moroccan Mediterranean, with an updated species checklist

Cnidarians play a crucial role in the marine ecosystem and are abundant in Moroccan waters, although their diversity remains poorly understood. This study aimed to assess the species richness of Cnidarians along the Moroccan Mediterranean coast through recent surveys and a literature review. A total of 104 Cnidarians species were identified in Moroccan waters. The recorded species were primarily distributed among different Cnidarian classes: 52% were Anthozoans (55 species), 38% were hydrozoans (40 species), 7% were scyphozoans (8 species) and less than 1% are Cubozoans. Notably, four Scyphozoans (Rhizostoma luteum, Cotylorhiza tuberculata, Phyllorhiza punctata and Cyanea capillata) and one hydrozoan (Porpita porpita) were reported for the first time in the Moroccan Mediterranean. Additionally, four species were identified as alien to this region. Evaluation of the Anthozoans species recorded in Moroccan waters using the IUCN red list for the Mediterranean region, revealed that 9 out of the 55 species (16.36%) were listed as threatened. These included 1 critically endangered species (1.81% of the total), 5 endangered species (9.09%) and 3 vulnerable species (5.45%). However, it is likely that the number of species on this list is underestimated due to the limited of studies conducted in the Mediterranean waters of Morocco. Therefore, further taxonomic and systematic studies of Cnidarians in Moroccan waters are crucial to provide a more comprehensive evaluation of the diversity of this group in this region.