Benthic habitats of western Mediterranean seamounts: Spatial modelling and environmental drivers

Seamounts are considered biodiversity hotspots that play a relevant role in deep-sea ecosystems. The LIFE IP INTEMARES project aimed to enhance scientific knowledge of the biodiversity and distribution of benthic species and habitats in the Mallorca Channel seamounts (Balearic Islands, western Mediterranean): Ses Olives, Ausias March and Emile Baudot. The present study develops spatial distribution models, based on the presence/absence of species or assemblages and environmental and fishing variables, to predict and map 11 potential biogenic benthic habitats and pockmarks fields. Data were collected using ROV, photogrammetric sledge, beam trawl and rock dredge. Seafloor was characterized by acoustic and sediment data. Hydrodynamic variables were obtained from models, and the fishing footprint derived from Vessel Monitoring System signals. Maërl/rhodolith beds, mainly overlapping with sponge gardens, were found on the circalittoral detritic sandy bottoms of the summits of the shallowest seamounts Ausias March and Emile Baudot. Sponge and gorgonian gardens were found on coralligenous outcrops and rocky flanks, while smaller sponges and pockmarks were widespread on deeper adjacent bottoms. Notably, the bamboo coral Isidella elongata was recorded on bathyal muds between Ses Olives and Ausias March. These results emphasize the ecological importance of the area and provide cartographic information to support the proposal of the Mallorca Channel seamounts as a Site of Community Interest for their inclusion in the marine Natura 2000 network.