Diversity and distribution of bivalve molluscs in the Central Cantabrian Sea and the Avilés Canyons System (Bay of Biscay)

Bivalve molluscs is one of the dominant benthic groups in soft-sediment communities off Atlantic Ocean, including European margin and Bay Biscay. The current knowledge deep-sea Euro-Atlantic bivalves their distribution still far from comprehensive has been scope several recent publications. We examined collected bivalve samples two oceanographic campaigns (COCACE BIOCANT) carried out central Biscay, Avilés Canyons System (ACS), a Site Community Importance within Natura 2000 Network. specimens were continental shelf, slope bathyal zones, ranging deep 25 to 4700 m. This first study focused on diversity Cantabrian Sea that covers such wide bathymetric range. Eighty-four live taxa 36 families identified; Cetomya neaeroides reported for time area. provide photographs showing shell diagnostic features all recorded species. conducted Multivariate Analysis showed three species assemblages: i) shallow waters (continental shelf); ii) intermediate depths (shelf upper slope) iii) water (slope abyssal plain). Depth was main structuring factor influenced higher richness found shelf. feeding strategy substrate preference appeared as not significant factors zonation patterns studied bivalves.