Seas around Canna rich in unusual marine wildlife

Largest area of fan mussels in UK

February 2012: The seas around the island of Canna on the west coast of Scotland are unusually rich in marine wildlife, according to a report published by Scottish Natural Heritage (SNH).

MUSSEL POWER: The fan mussels found in the rich mud off the coast of Canna. Picture: George Brown

A survey carried out by marine biologists from SNH and Marine Scotland in 2010 revealed species and habitats of high conservation value in the Sound of Canna, a steep sided channel that runs between the islands of Canna and Rum. The underwater landscape of rock walls, glacial moraines, boulder piles and sheltered areas of mud and sand provide a wide variety of wildlife habitats.

An area of rare fan mussels, first spotted in 2009, has now been confirmed as the largest in UK waters. With well over a hundred mussels covering more than 170 hectares, it was much bigger than originally expected. Once common around Britain's coasts, only a handful of scattered individuals have been recorded in the past 20 years, making them one of the UK's most endangered shellfish.

'We are surprised and excited by what we found'
Northern feather stars, an animal with several feather-like arms used for swimming and catching food, were found on deep sediment at both entrances to the channel. Burrowed mud, an internationally important habitat that is home to burrowing animals and the nationally scarce sea pen, covers much of the seabed.

And excellent examples of northern sea fan and deep sponge communities were found on the cliffs around the nearby island of Sanday, on deep rock outcrops and on the floor of the Sound.

Laura Clark, SNH's project manager for the Canna survey said: ‘Until the discovery of the fan mussels during a routine survey a couple of years ago, the Sound of Canna attracted relatively little attention from marine biologists.

'It's great to see this huge variety of marine life in such a small area'
‘What we found when we returned to survey the area in detail surprised and excited everyone involved, particularly the extent of the fan mussel bed. It was great to find such a huge variety of marine life in such a small area.'

The survey is one of several which have taken place around Scotland since 2010, to better understand the distribution and quality of marine wildlife in Scottish waters. They are part of an extensive programme of work carried out by Marine Scotland, the Joint Nature Conservation Committee (JNCC), SNH and Historic Scotland. The information gathered will be used to advise Scottish Ministers on potential locations for marine protected areas, helping Scotland meet international commitments to create a network of sites in Scottish waters.