Copepods distribution patterns in an upwelling system off Northwest Africa (Southern Moroccan Atlantic coast)

In order to assess copepods distribution and diversity within southern Atlantic Moroccan coast, two surveys were carried out between Cape Blanc (21°N) and Cape Boujdor (26°N) during two seasons (fall and summer). Copepods were clearly predominant (more than 90%) in both seasons followed. During fall copepods composition were dominated by the species Oncea venusta (44%), Clausocalanus arcuicornus (18%) while in summer Acartia clausi (18%) and Clausocalanus arcuicornus (15%) were the most abundant. Referring distribution maps of densities and structural indexes of the population, obvious differences were identified between southern and northern parts of Dakhla (24°N). Indeed, the southern area remained the richest and most diversified as clusters analyses of copepods densities corroborated these results, thus two principal groups were distinctly identified. Similarly, distribution maps of hydrological parameters have depicted two distinguish areas separated by Dakhla region (24°N). These results were confirmed by Mann-Whitney U test performed on northern and southern densities and environmental parameters.