Benthic habitat characterisation of soft-bottom continental shelves: Integration of acoustic surveys, benthic samples and trawling disturbance intensity

12 pages, 6 figures, 4 tablesEleven sites were located on Mediterranean continental shelves to explore the link between the physical characteristics and epibenthic fauna from soft-sediment habitats. These sites, at 32–82 m in depth, were associated with fishing grounds and the trawling intensity was estimated at the site scale to assess the effects of trawling on benthic communities. Each site was surveyed with Multi-Beam (bathymetry and backscatter), side-scan sonar, benthic grabs and a surface dredge. The sites were clustered in three habitat types. Habitat 1, with moderate trawling disturbance, was characterised by homogeneous mud and associated epifauna that was also highly homogeneous across sites. Habitat 2, with sandy mud and scattered gravel and rocks, had a high abundance of sessile suspension feeders that probably attach to the coarser substratum and benefit from the low fishing disturbance in these sites. Habitat 3 included sites with heterogeneous sediments with maërl as the prevailing biocenosis and having the highest species richness, despite being subjected to variable trawling intensity. Statistical models were used to relate environmental parameters and the species abundance. More than 3 physical variables were necessary to explain the epifaunal patterns across sites, including the percentage of mud, sediment heterogeneity and fishing effort. These analyses are an essential step for extrapolating information from benthic samples to the larger scale of habitats, mapped through acoustic surveys. Despite this, a good integration is required between the mapping of physical habitat distribution and the ecological knowledge of communitiesThis study was funded by the research project COMSOM (CTM2008-04617). The authors would like to thank all participants in this project for their invaluable help and the crew from the RV Garcia del Cid for their help and enthusiasm during the cruise (CTM2008-04206-E/MAR). We acknowledge the postdoctoral mobility grants from The Spanish Ministry of Education (programa nacional de movilidad de recursos humanos del Plan Nacional I+D+i 2008-2011) and the Marie Curie Action of the EU’s Seventh Framework Programme (FP7/2007e2013), EIF GeoHabit e PIEF-GA-2011-298274Peer reviewe