Thumbnail

Flame shell beds

The flame shell or file shell is a bivalve mollusc that forms dense beds, which may support hundreds of species.

Flame shells (Limaria hians) live hidden on the seabed in nests, which they build from shells, stones and other materials. Hundreds of nests can combine to form a dense bed, which raises and stabilises the seabed and makes it more attractive to many other creatures.

Flame shell beds are a Priority Marine Feature in Scotland's seas and provide habitat for all sorts of other life, increasing biodiversity, so it's critically important that we protect them.  A Loch Fyne study found that six nest complexes supported:

  • 19 algae species and
  • 265 invertebrate species

Flame shell beds offer good attachment for scallop spat, which fall from plankton and young fish are often associated with the beds. Individual flame shells, which grow up to 4cm in length, may also live under stones or in kelp holdfasts.

This habitat is found mainly on the west coast of Scotland, with the largest known flame shell bed in Loch Carron. Individuals have been found at depths of 100m, while flame shell beds usually occur at depths of between 5m and 30m, though they can be found from the low-tide mark. Flame shell beds develop mostly on seabeds of coarse sand, gravel and shells, often in areas with moderate or strong water currents.

Extensive flame shell beds are rare, some of our best examples are in sea lochs e.g. Loch Alsh.

Information on where flame shell beds are found is at Scotland's National Marine Plan Interactive (NMPi).

Threats to flame shell beds

Flame shell beds are vulnerable to mechanical disturbance, particularly from bottom trawls and dredges.  Damage caused by fishing activity to an area of flame shell bed in Loch Carron in 2017 resulted in the creation of an emergency Marine Protected Area.  Flame shell beds are also sensitive to changes in water quality and siltation.

More information on the sensitivities of flame shell beds can be found at Scotland's Feature Activity Sensitivity Tool (FeAST).

Protection of flame shell beds

Flame shell beds are a priority marine feature in Scotland’s seas a UK BAP habitat and an OSPAR threatened and declining habitat.  

Flame shell beds are protected in 6 locations around Scotland by a suite of Marine Protected Areas shown in the map below.  More information on the sites and how they are managed can be found at SNH's Sitelink and on the Marine Scotland web pages for some sites.  For a number of sites detailed survey and monitoring reports also exist.

Map of flame shell beds in the UK

Find out more

Watch the videos Loch Carron Marine Protected Area and A flame shell on the move, on our YouTube channel: