Asociaciones de decápodos de fondos blandos circalitorales y batiales del mar de Alborán

Abstract

Beam-trawl samples were collected during the MEDITS survey in 2014. These samples covered the continental shelf and slope bottoms of the north Alboran Sea, including the Alboran Island, between 40 to776 m depth. The decapod crustaceans were identified to species level and quantified (abundance and biomass). Species richness (S), Shannon-Wiener diversity index (H’), evenness (J’) and functional diversity index was calculated after identifying and quantifying all decapods collected in each sample. A total of 84 species have been found, dominating the families Paguridae (14 spp), Inachidae (10 spp) and Pandalidae (8spp) in relation to number of species. The dominant species were Plesionika heterocarpus, Alpheus glaber and Calocaris macandreae, in terms of abundance and P. heterocarpus and Monadeus couchii in relation to biomass. Both depth and nature of the substrate characterized the different decapod assemblages. Functional diversity and J’ showed a positive correlation with depth, unlike abundance and biomass. On the continental shelf assemblages were dominated by a low number of species with high abundances, however those from the upper and middle slope showed higher evenness and a wide variety of functional groups. The Atlantic influence of the Alboran Sea favors the presence of a high number of species with Atlantic affinity.