Loch Sween NCMPA

Status: Designated


Site overview

This is an important area for mud, and all the animals that live in mud! These include volcano worms, Norway lobsters, shrimps and burrowing gobies. Maerl beds also flourish here. A dense bed of hedgehog maerl runs down the central part of the Caol Scotnish. These create important habitats for other species such as feather stars, scallops, sponges, crabs and fish. Native oysters occur in patches throughout the Loch, which provide food for the otters that live here. Once common in Scotland and supporting a grand shellfish export industry, beds of native oysters now only exist in a few scattered locations. The population within Loch Sween is considered to be of national importance. 

MPA Type

Nature Conservation Marine Protected Area

Nature Conservation Marine Protected Areas (NCMPAs) are designated under UK legislation (Marine Scotland Act 2010) and have been established around Scotland to contribute to the UK MPA network by protecting a range of important habitats, species and features of the seabed.

Designation date

24 July 2014

Surface Area

40.66 km2 (15.70 mi.2)


145.85 km (90.62 mi.)

  • Native oysters (Ostrea edulis)

    Native oysters are two shelled animals - one half is like a cup and attaches to the rock, the other is flat and forms a lid. These oysters have been farmed for food since Roman times and the shells are a common find in archeological digs. 

  • Burrowed mud

    Burrowed mud is a surprisingly important marine habitat which supports a rich community of animals.   There are the burrow-making animals that live within the mud itself, including fish, worms, brittlestars, crabs and shrimps.  Secondly, there are those a

  • Sublittoral mud and mixed sediment communities

    Mud and other sediments below the low water mark which can support a rich variety of life including shellfish, anemones and worms.

  • Maerl beds

    Maerl beds include several species of red seaweed, with hard, chalky skeletons. Maerl is rock hard and grows, unattached to the seabed, in little nodules or branched shapes on the seabed. Each bit is quite small, but they can accumulate in large areas tha

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Loch Sween contains serpulid reefs, a priority fragile biogenic reef habitat, and maerl beds, another priority habitat. It is the target for focused monitoring survey dives to ascertain the extent and status of these habitats.

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Did you know?…

Over 170 parliamentarians from across the political spectrum signed up to our Marine Charter calling for a network of ‘marine protected areas’ in UK Seas

Over 500,000 records of undersea species and habitats have been collected by volunteer Seasearch divers