Spatial distribution of demersal and epibenthic communities along the northern Atlantic waters of Morocco -North West Africa-

The composition and abundance of demersal and epibenthic communities along the northern atlantic coast of morocco were studied. eighty two bottom trawl hauls were carried out in july 2010,at depths ranging from 20 to 800 m. one hundred forty eight species have been identified. most of them belonged to the fish groups,followed by crustaceans,cephalopods,gastropods,echinoderms,cnidarians and bivalves. only european hake (merluccius merluccius) was considered frequent because this species was present in more than 75% for all depth strata. as a result of multivariate analyzes,four assemblages were defined. the group i,was located from 200 to 300 m,on the muddy-sands bottoms on the outer continental shelf and the upper slope,and characterized by high abundance and high diversity. the group ii,distributed on trawlable bottoms between 100 to 200 m,limited and influenced by the rocky and coralligenous grounds. the group iii,localized on the middle slope,beyond 300 m depth,on muddy bottoms and characterized by deep sea species. the group iv,situated in less than 100 m depth on sandy-muddy bottoms and characterized by typical shelf species. each assemblage was characterized by specific species and had both qualitative and quantitative differences. depth appeared to be the main structuring factor of demersal and epibenthic communities in the northern atlantic coast of morocco. the substrate type seems also,play an important role in this structuration.