The purpose of this survey was to initiate site condition monitoring of the biogenic and rocky reefs of Loch Creran. This survey took place between the 11th July and 23rd December 2005, run by Heriot Watt University for NatureScot (Scottish Natural Heritage at time of survey). The extent and distribution of serpulid reefs was determined from observations by divers along 110 transects around the loch between 11th-25th July 2005. Detailed studies were also performed at four of the major serpulid reef sites in the loch; distribution of the serpulid reefs was examined with sidescan sonar between 6th-8th September 2005, reef density by video and the community of organisms associated with the habitat by diver survey of the reefs themselves and of the surrounding sediment was undertaken between 23rd-26th July 2005. The distribution and abundance of Modiolus was also examined along seven relocatable transects and, at one of the major mussel beds, the size structure of the population and associated community surveyed.