The purpose of this benthic survey in the Sound of Canna was to conduct a detailed survey of seabed MPA search features within the sound, with particular emphasis on the population of fan mussels (Atrina fragilis). Survey work during August and September 2010 involved a drop-down video survey to capture footage of the seabed habitats at 121 stations; detailed in-situ, diver observations, which included mapping the extent of seagrass beds and the collection of infaunal core samples at 15 stations; and grab sampling at 23 stations within benthic sediment communities. The primary objective of the work was to provide an assessment of the current status of the fan mussels. The survey plans were developed from previous sampling records, Admiralty charts, and predictive habitat distribution maps covering this area. This sampling work was carried out in 3 phases. Video and grab sampling were undertaken in shallow water between the 5th-7th August by Aquatic Survey and Monitoring Ltd (ASML) and SNH from the survey vessel Lophelia, and in deep water between the 20th and 27th September by ASML and University Marine Biological Station on Millport (UMBSM) from the UMBSM research vessel RV Aora. Diver fieldwork was carried out by a team of 4 divers from the 28th August to 4th September from the vessel Lophelia. The images and infaunal samples, analysed under SNH contract by ASML and Identichaet, were used to describe the nature of the seabed in terms of the physical structure and the species assemblages.
