The Heriot-Watt Scientific Dive Team is nearing the end of a three week survey of the Isle of Mousa in Shetland. They were last at this site in 2008 when they investigated the biological communities of rocky reefs and sea caves around the island. Mousa is part of Scotland's network of Special Areas of Conservation set up to protect certain marine habitats and their associated communities of animals and seaweeds.
The purpose of the current visit was to assess changes in these biological communities and determine if there is any evidence of deterioration in their richness and quality. The work was funded by Scottish Natural Heritage and is part of their wider objective of monitoring the biological condition of Scotland's marine environment.
In addition to the Heriot-Watt marine biologists the team included a representative from Scottish Natural Heritage and specialist underwater photographers Richard Shucksmith and Robert Cook. They were also assisted by a representative of National Museums of Scotland in the management of numerous biological specimens destined to be added to the national collections.
The first two weeks of the project were occupied by diving surveys and shore work. The last week involved the use of a video system lowered to the sea bed from the boat allowing the team to visit deeper parts. Despite losing a number of days to unseasonal gales succeeded in visiting all planned sites.
It will be several months before the data, imagery and video footage is fully processed but the initial impression is that the biological condition of these habitats remains excellent with no sign of deterioration since 2008. Highlights included the profuse gardens of soft corals that dominate many of the deeper areas of rock around the island and octopus were unusually common. Sightings of these bizarre and complex animals are normally very infrequent in Scottish waters but it is known they have become more common in northwest Scotland over the last year or so and it is now clear that they are also on the rise in Shetland.