This project aims to map the broadscale biotopes and habitats of the rocky reef sites west of the Outer Hebrides through integrating multibeam echosounder data, acoustic grounddiscrimination system (AGDS) data, underwater video/camera surveys and grab data, facilitated through the use of GIS. Where possible, biotopes have been resolved and classified using the National Marine Habitat Classification for Britain and Ireland (Connor et al, 2004), and suggestions are made as to their conservation value at a regional, UK and European level.