The main aim of this investigation in Loch Fyne and Clyde Sea was to improve knowledge of the occurrence and distribution of the species and habitats, especially PMFs. A drop-down video survey and a grab survey of benthic habitats was undertaken by SNH from the 12th to 18th March 2012. Underwater video footage was collected using DDV camera system at 108 sites in Loch Fyne, Inchmarnock, Arran, Kilbrannan Sound and Clyde Sill. Analysis of seabed video and still photographic imagery is used to describe the nature of the seabed in terms of the physical structure and the species assemblages. Runs and run segments were assessed for the presence of protected features and other PMFs, as well as for the presence of species and habitats of recognised conservation importance. On the same survey, SNH collected grab samples for infaunal analysis at 28 stations in the Clyde Sea for Marine Scotland. The SEPA vessel Sir John Murray was used for this survey work.