This report is a contribution to the Strategic Environmental Assessment (SEA7) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). The SEA 7 area, especially the Hebrides slope and areas of the Rockall Trough has been significant in the development of deep-sea biology since the 19th century. In recent decades intensive sampling has been undertaken by researchers from UK institutions such as the Scottish Association for Marine Science (formerly the Scottish Marine Biological Association) and the National Oceanography Centre, Southampton.

The entire SEA 7 area is contained within the biogeographic region known as the Atlantic Deep-Sea Province, with the major oceanographic variables defined by the passage of North Atlantic Deep-Water. To the south, concentrated research efforts have taken place in areas such as the southern Rockall Trough, Porcupine Seabight and Porcupine Abyssal Plain. These encompass similar hydrographic and oceanic conditions to those of the SEA 7 area and form a basis for comparison.

A brief overview of the history of deep-sea research in the SEA 7 area is provided here, along with a summary of the physical environment. In this report, however, the main focus is the ecology of seafloor-dwelling organisms. The ecology of benthic communities is described with respect to large-scale trends and is discussed in the context of how anthropogenic influences may affect the benthos.