A colourful catalogue showcasing the rich biodiversity in Scotland’s seas has just been published on our website. Illustrated with photos and maps, the intriguing catalogue describes Scotland’s 81 Priority Marine Features (PMFs). PMFs are the habitats and species considered to be conservation priorities in Scottish waters. Morven Carruthers from our marine team, who managed the catalogue’s production, tells us about two of her favourite features on the list.

Close-up of the fleshy mantle and bright red filamentous tentacles of a flame shell. © Graham Saunders/Marine Scotland

Flame shells are rarely seen but beautiful creatures. Scientific name Limaria hians, they are bivalve molluscs about 4cm long, with blazing orange-red tentacles that stick out between their shells. Despite their fiery appearance they’re not easy to spot underwater because they tend to spend most of their lives hidden away in nests built in the sea floor sediment.

They build their nests by weaving tough (byssus) threads with seaweed, shells and gravel. Neighbouring flame shell nests combine together to form a dense bed, which in some areas can carpet the sea bed for many hectares with thousands of flame shells.

Flame shell beds tend to be rich in marine life because they stabilise the seabed sediments and provide a surface to which other animals and seaweeds can attach. Sea firs, peacock worms, anemones, sponges and red seaweeds colonise the bed itself, providing shelter and hunting grounds for fish, crabs and whelks.

Close-up of a flame shell bed. © Suzanne Henderson/SNH

Flame shell beds are one of 26 ecologically important habitats on Scotland’s PMF list; all places vital for local biodiversity, which provide the foundations for a whole community of marine life to flourish. But they are fragile places; flame shell beds are especially susceptible to seabed disturbance and recent evidence suggests that a flame shell bed may take more than 100 years to re-establish following a dredging event.

Scotland’s west-coast sea lochs are home to the densest flame shell beds in the UK, including the largest known flame shell bed in the world, in Loch Alsh. This was discovered in 2012 as part of our work to identify Nature Conservation Marine Protected Areas (MPAs). The 93 hectare bed stretches through the tidal Kyle Akin narrows under the Skye Bridge and out into the Inner Sound. In 2014 the Lochs Duich, Long and Alsh MPA was designated to provide protection to an estimated 100 million flame shells!

Peacock worm group with kelp detritus on a flame shell bed. © Ben James/SNH

Scotland’s coasts and seas are home to around 8,000 animal and plant species and we use the PMF list to help target our work to conserve this fantastic marine biodiversity. Other habitats described in the catalogue include seagrass beds, northern sea fan and sponge communities, cold-water coral reefs and intertidal mudflats.

A blenny sheltering in a seagrass bed. © Ben James/SNH

There are 55 species on the PMF list, including some creatures with limited mobility, such as the fan mussel, heart cockle and pink sea fingers; as well as mobile animals like Atlantic salmon, anglerfish, Portuguese dogfish, long-finned pilot whale and the European spiny lobster. Each description includes the feature’s characteristics, environmental preferences, distribution and status, alongside a photo, map and references for those who want to find out even more.

Risso’s dolphin is one of several cetacean PMFs. This species has a distinctive rounded head, with no discernible beak, and can grow up to about 3.8 metres in length. Risso’s dolphin calves are born a uniform grey, turning a darker grey/ brown as they become juveniles. Adult Risso’s dolphins sometimes appear much lighter due to white scarring along their body, which can become extensive over time. The scars are thought to be caused by other Risso’s dolphins, as well as from underwater tussles with squid, their main prey.

Risso’s dolphin. ©Nicola Hodgkins/Whale and Dolphin Conservation (WDC)

One of the best places to see Risso’s dolphin in Scotland is off the north-east coast of the Isle of Lewis. Photo-identification surveys by Whale and Dolphin Conservation have identified individual animals in the area over several years, suggesting that some of the Risso’s dolphins here may be semi-resident. The presence of mothers with calves, and groups of juveniles, suggests these waters could be important for breeding, nursing and raising young, as well as good for food. The Scottish Government is currently considering recommendations to designate an area off North-east Lewis as an MPA to protect the dolphins.

Risso’s dolphin mother and calf. ©Nicola Hodgkins/Whale and Dolphin Conservation (WDC)

Descriptions of Scottish Priority Marine Features is aimed at anyone who wants to know more about our PMFs, from specialists to students and enthusiastic amateurs. Scotland’s seas are amongst the most biologically productive in the world and the catalogue gives a real flavour of the extraordinary diversity of life they support. It’s also a reminder of how sensitive marine life can be and the importance of balancing human activities at sea.

Produced in partnership with Marine Scotland and the Joint Nature Conservation Committee (JNCC), you can download Descriptions of Scottish Priority Marine Features free of charge from our website.