South of Portland MCZ

Status: Proposed


Site overview

The stone for St Pauls Cathedral, the Tower of London and Buckingham Palace, originated on Portland. The powerful Portland Race, a raging tidal flow that runs south and north past Portland Bill, has gouged the 100m Portland Deep into the soft seabed rock south of the Isle of Portland. It’s a unique geological feature that’s filled with marine wildlife. The crags and canyons provide a home for a high diversity of invertebrates, such as anemones, sponges, sea squirts and pink sea fans, that cling on in this dynamic habitat. Beyond the Deep lie blue mussel beds, providing a more sheltered habitat for a variety of fish and invertebrates.

Designation of this Marine Conservation Zone in 2019 will protect this unique site and its marine wildlife for future generations.

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

17.49 km2 (6.75 mi.2)


18.00 km (11.19 mi.)

  • 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.

  • High energy circalittoral rock

    Rocky areas affected by strong waves or currents where the water depth means there is not enough sunlight so marine animal communities like sponges, sea firs and soft corals dominate and seaweeds are mostly absent.

  • Portland Deep

    An enclosed rock basin and an example of tidal scour field. This feature supports a range of species including anemones, sponges, sea squirts and pink sea fans and fragile ross.

Seasearch Logo

Seasearch survey dives are planned for Summer 2018. This is a very challenging site to dive, being up to 80m deep (well beyond normal limits for recreational SCUBA divers) and subject to very strong tidal streams. It is notable for its geological feature (Portland Deep) and high diversity of life on the seabed.

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

An area over 9 times the size of Wales is now in marine protected areas in the UK, but less than 1% is considered by MCS scientists to be well managed