Information of bathyal non-crustacean invertebrates is scarce in the Mediterranean Sea, especially in submarine canyons. The present study reports new data about these bathyal groups inhabiting in deep canyon areas of the north-western Mediterranean Sea. A total of 259 deployments were completed in Blanes, La Fonera and Cap de Creus canyons and the adjacent open slope and, between 850 and 3000 m depth. Samples were realized by means of otter-trawl Maireta system (OTMS), Agassiz trawl, epibenthic sledge and Remote Operated Vehicle (ROV). The density and biomass of non-crustacean invertebrates resulted significantly higher (more than twice) in canyon areas than in surrounding open slope. Two species sampled inside canyon were reported for the first time in the Mediterranean Sea: the carnivore ascidian Dicopia antirrhinum C. Monniot, 1972, and the regular echinoid Gracilechinus elegans (Düben & Koren, 1844). Both species were observed more than five times, suggesting a large presence which has been largely overlooked in deep Mediterranean canyons. Cold water corals were also detected by ROV as Desmophyllum dianthus (Esper, 1794), Madrepora oculata Linnaeus, 1758 and Lophelia pertusa (Linnaeus, 1758). Finally, large aggregations of the irregular echinoid Brissopsis lyrifera (Forbes, 1841) were described. All these data suggested the north-western Mediterranean canyons as hot spots for biodiversity and abundance of resident benthic fauna, and indicate the need for increased sampling effort with new technologies in these ecologically relevant habitats

The 2nd International Symposium on Submarine Canyons (INCISE2014), 29th September-1st October 2014, Edinburgh.-- 1 page, 2 figures

Peer Reviewed