Demersal and Epibenthic Communities of Trawlable Grounds on the Mediterranean Coasts of Morocco (South Alboran Sea)

The Alboran Sea is a transitional water body between the Mediterranean Sea and the Atlantic Ocean. The northern region has been the subject of more extensive research than the southern region. In this paper, the authors focused on the composition and abundance of demersal and epibenthic assemblages in the southern Alboran Sea, along the Moroccan Mediterranean coast. The analysis is based on data from 18 stations sampled along the continental shelf at depths ranging from 62 to 472 meters. 122 species were identified, the majority of which were fish, followed by mollusks, crustaceans, echinoderms, and cnidarians. To characterize the assemblage structure, the Hierarchical Ascending Classification and non-Metric Multidimensional Scaling was employed. These analyses revealed a clear bathymetric segregation along the continental shelf, forming three distinct groups: 1) Inner shelf – stations shallower than 100 meters; 2) Outer shelf – stations between 100 and 200 meters, and 3) Upper continental slope (UCS) – stations deeper than 200 meters. Species richness, diversity, and evenness followed consistent bathymetric trends. The main indicator species for each depth stratum were: Dardanus sp. (6.69%) for the Inner shelf, Sepia orbignyana (9.67%) for the Outer shelf, and Phycis blennoides (9.59%) for the UCS. Our findings provide a baseline dataset for future monitoring and management of demersal and epibenthic populations in this area, which is of intrinsic interest due to its value as a trawlable fishing ground.