Flame shells (scientific name Limaria hians) are small bivalve molluscs that construct intricate nests from shells, stones, seaweed and maerl. These form dense biogenic beds in tide-swept, muddy sediments, at depths of around 5 – 30 metres.
They take their name from their bright orange tentacles which emerge from their shells to collect food. The shells also produce sticky threads which combine small stones and shell debris to create a nest.
When many of these nests form together, a flame shell bed is created, able to shelter hundreds of other organisms in a reef-like structure, which creates nursery grounds for many species of fish and shellfish.
Flame shells grow to 2.5-4cm across but their beds can contain over 100 million individual flame shells, covering over 75 hectares. They favour relatively shallow water with a moderate or strong current.
In Scotland, flame shells are mainly found along the west coast in sea lochs and narrows. This includes the world’s largest known flame shell bed in Loch Carron, along with beds in Loch Alsh, Loch Sunart, Loch Goil, and Loch Linnhe – to name just a few examples.
Flame shells are classed as a Priority Marine Feature, and several Marine Protected Areas (MPAs) have been designated to protect them in Scottish waters.
Photo: © Cathy Lewis / Marine Conservation Society
Action Needed
- Call for further measures to protect flame shell beds, including through the forthcoming, and long-awaited, fisheries management measures for inshore MPAs and Priority Marine Features (PMFs).
- Highlight the success of restrictions on bottom-towed gear in Loch Carron, which were implemented in 2017 and have allowed the site to recover from previous damage, as a prime example of effective fisheries management measures.
- Push the Scottish Government to implement the Scottish Biodiversity Strategy, and any statutory nature recovery targets which are created following as a result of the Natural Environment Act.
- Encourage the Scottish Government to adopt spatial management of fishing when finalising the Inshore Fisheries Management Improvement Programme (IFMI). A system of spatial management could ensure further protection for PMFs including flame shells.
Threats
- Damaging forms of fishing – those using bottom-towed gear – can cause severe damage to flame shell beds, such as happened in outer Loch Carron from scallop dredging in 2017
- Pollution, from sources such as fish farms, sewage or agricultural runoff, can affect the long-term health of flame shell beds.
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