The Manacles MCZ

Status: Designated


Site overview

Located on the southern coast of Cornwall this site extends 2 km from the coastline to encompass a series of large underwater rocky outcrops, known as The Manacles - which the site is named after. These rocky outcrops have been the site of many shipwrecks, which over time have been colonised by some of the species found in this area. The seabed varies hugely throughout the site and includes vertical rock faces and rocky reefs. This area is home to well-known species such as sea fans and anemones, as well as commercially fished species including common lobsters and crabs. The seabed also supports important marine maerl beds, a type of red seaweed. As this grows it deposits lime in its cell walls, creating a brittle skeleton. This, combined with slow growth, means that maerl is vulnerable to damage.  The site supports a number of interesting animals such as the spiny lobster, the tiny stalked jellyfish and small sea fan anemones. Sea-fan anemones can group together to form large, closely-packed colonies. Their unusual method of reproduction leaves behind a train of fragments from the base of its body, which grow into new genetically identical anemones.

MPA Type

Marine Conservation Zone

Marine Conservation Zones (MCZs) are designated under UK legislation (Marine and Coastal Access Act 2009) and have been established around England, Wales and Northern Ireland to contribute to the UK MPA network protect a range of nationally important marine wildlife, habitats, geology and geomorphology, and can be designated anywhere in English and Welsh territorial and UK offshore waters.

Surface Area

3.49 km2 (1.35 mi.2)


9.97 km (6.19 mi.)

  • Spiny lobster (Palinurus elephas)

    Crustaceans named for the sharp spines all over their heavy, orange-brown shells. They used to be fished commercially, but numbers have decreased dramatically and this species has disappeared entirely from some parts of England where they were common.

  • Pink sea-fan (Eunicella verrucosa)

    A soft coral, related to tropical species and one of the most exotic-looking of our seabed animals. These delicately branched colonies of tiny animals are in turn home to other creatures.

  • Sea-fan anemone (Amphianthus dohrnii)

    A tiny anemone, about 1cm across, that lives with it’s base wrapped around a pink sea fan. They are found only in a few locations around the UK.

  • Stalked jellyfish (Haliclystus auricula)

    Bell-shaped, jelly-like, eight-armed animals that have a stalk and a sucker which they use to attach to marine plants, rocks or the seabed. Some species can move and do so by cartwheeling.

  • Moderate energy circalittoral rock

    Deeper water rock, with some shelter from waves and currents.

  • Subtidal sand

    Sandy seascapes that can seem a bit like deserts, but can be full of life. Flat fish and sand eels camouflaged on the surface of the sand,worms and bivalves (with their paired, hinged shells) all live in places like these.

  • Subtidal coarse sediment

    Undersea beds of coarse sand, gravel and shingle. Most of the animals that live here, like bristleworms, sand mason worms, small shrimp-like animals, burrowing anemones, carpet shell clams and venus cockles, are found buried in the seabed – the safest pl

  • Subtidal mixed sediments

    Undersea beds of a mixture of stones, gravels, sands and muds. Because mixed seabeds are so varied, they may support a wide range of animals, both on and in the sediment.

  • Moderate energy intertidal rock

    Rocky seashores, above low tide, with some shelter from waves and currents. On these shores, there are places where plants and animals can find shelter from the waves – the landward sides of boulders, in cracks and crevices, and in rock pools.

  • Intertidal coarse sediment

    Where small rocks, pebbles, and gravel, sometimes mixed with coarse sand are sometimes covered by the tide. While it may not look like much lives there - there are animals specially adapted to live in the moist spaces between the shingle and gravel.

  • Moderate energy infralittoral rock

    Shallow water rock, below the tides, with some shelter from waves and currents.

  • Subtidal macrophyte dominated sediment

    Underwater beds of pebbles, gravel, sand or mud, where seagrass or seaweeds grow. They may be important refuges for young fish and shellfish.

  • 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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Seasearch has surveyed this site on a number of occasions. They were involved in detailed surveying of the reefs and channels in order to gather information on the potential effects of the development of Dean Quarry, as well as investigating similar reef habitat to the south of the exisiting site in support of an extension to it. These divers have also monitored the pink sea fans in this area. It was found that there are extensive populations on the flatter rock and boulder seabed in this site. These surveys confirmed that these areas have healthy sea fan populations. The reefs are also home to many of the burgeoning population of crawfish or spiny lobster in the south west.

Learn more about Seasearch

Did you know?…

To the shelf limits, Scotland has 61% of UK waters, of which 23% are now in existing or new ‘marine protected areas’

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