The Ligurian Sea is one of the most studied Mediterranean basins. However, a large knowledge gap exists about the composition of benthic communities extending into the so-called mesophotic or twilight depth range, currently under intense pressure from commercial and recreational fishing.

This study undertook a series of visual surveys, carried out by means of remotely operated vehicles between 2012 and 2018, along the Ligurian deep continental shelf and shelf break (30-210 m depth) in order to characterize the main benthic biocoenoses dwelling at this depth range and to determine the most relevant environmental factors that explain their spatial distribution.

The obtained results show that deep circalittoral communities of the Ligurian Sea are represented by a mixture of species belonging to the deepest extension of shallow-water habitats and deep circalittoral ones. Twelve major biocoenoses were identified, including gorgonian and hydrozoan forests, dense keratose sponge grounds, Dendrophyllia cornigera gardens, bryozoan beds and soft-bottom meadows of sabellid polychaetes and soft-corals. The authors state that less common aggregations were also found, including six forests of black corals and two populations of Paramuricea macrospina.

It is highlighted that a georeferenced database has been created in order to provide information to managers and stakeholders about the location of the identified communities and high-diversity areas, aiming to facilitate sustainable long-term conservation of the Ligurian benthic ecosystem.

Enrichetti et al. (2019) Megabenthic communities of the Ligurian deep continental shelf and shelf break (NW Mediterranean Sea). PLoS ONE 14:e0223949.