Study to uncover secrets of Scotland’s seabed

A diving expedition is under way to uncover the secrets of giant horse mussels on Scotland’s seabed.

A horse mussel (Modiolus modiolus) with brittle stars. Picture: PA

Researchers from Edinburgh’s Heriot-Watt university have headed to Scapa Flow, Orkney to examine the habitat of the mussels which can grow to 25cm-long, equivalent to a size nine shoe, and can live for up to 50 years.

The team hopes to conduct 100 dives over the next two weeks.

William Sanderson, from the university’s school of life sciences, said: “Due to their longevity, they’re not really edible. They are rumoured to be quite tough and probably have quite a lot of muck in them, but their age is also a fantastic way for us to discover clues about the environmental quality of their habitat and what we can do to protect these cold water reefs from damage.”

It is hoped that information gathered on the expedition will help scientists develop ways to monitor the environmental quality of the mussel beds. They will look at ways to restore damaged beds and examine how the creatures give shelter and nutrition to other sea life.

Wildlife and underwater photographer and writer Richard Shucksmith is accompanying the team, documenting the dive and life onboard the research vessel Sunrise, with daily posts appearing on the group’s Facebook page.

The university previously explored the largest horse mussel reef found to date in Wick, said to cover the same area as 380 football pitches, and a reef in Wales which contained almost 300 species and 5,000 individual animals in an area the size of two sides of an A4 sheet of paper.

Dr Sanderson said: “We’re really looking forward to documenting these biodiversity hotspots off the coast of Orkney where tens of billions of organisms can be found living on just one horse mussel reef. The giant horse mussels are fascinating creatures, though you would not necessarily serve them up as a gourmet treat.”