Allonby Bay MCZ

Status: Designated


Site overview

Allonby Bay is a long, crescent shaped sand and shingle beach, surrounded by shallow waters.  It stetches for five miles around the coast into the Solway Firth (which is a designated Area of Outstanding Beauty in Cumbria) and contains two extremely important areas for marine life, Dubmill Scar and Maryport Roads. The 39km square area is incredibly diverse, it has many different species of sponge, soft coral, seaweed, sea squirt, anemone and reef-building honeycomb worms. The honeycomb worm reef, a key feature here, prevents sediments from shifting and provides a home for lots of marine wildlife. Allonby Bay contains some of the best examples of reef in the north west. About 300 species of algae are found in the Solway area. Some wonderfully named creatures live here too, such as the baked bean sea squirt and the breadcrumb sponge. Harbour Porpoises can be seen on a daily basis in the waters around Silloth. Also, Allonby Bay is believed to be a spawning and nursery ground for plaice, skate, seabass and thornback rays.

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

39.08 km2 (15.09 mi.2)


24.54 km (15.25 mi.)

  • 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.

  • Seagrass beds

    Seagrasses (also known, for their long thin leaves, as eel grass) are grass-like flowering plants with dark green, long, narrow, ribbon-shaped leaves. They are one of the very few groups of flowering plants that live in the sea.

  • Intertidal biogenic reefs

    A biogenic reef is a reef made from the hard parts of living things. In England honeycomb worms and mussels both form this type of reef where they occur in large numbers.

  • High energy intertidal rock

    Rocky seashores, exposed to very strong waves and currents.

  • 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.

  • Low energy intertidal rock

    Rocky seashores, sheltered from waves and currents dominated by seaweeds and exposed at low tide.

  • Intertidal sand and muddy sand

    The beach! Sandy shores are made up of clean sand or slightly muddy sand, often scattered with seashells and stones. The surface is often ‘rippled’ by the action of waves. Below the surface worms and shellfish stay safe and damp.

  • 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 biogenic reefs

    Underwater reefs made from the hard parts of living things. Coral reefs are the most recognisable example. In the Uk we have reefs made by tubeworms and mussels. They provide a great habitat for lots of other life.

  • Blue mussel beds (Mytilus edulis)

    These small, blue mussels are a common sight on UK coasts and form large beds in some places. They are particularly important where they create a haven for other creatures like starfish, crabs and anemones in otherwise sandy or muddy areas. 

  • Honeycomb worm reefs (Sabellaria alveolata)

    Honeycomb worms build tubes from sand and shell fragments. Where these worms life close together their tubes from large reefs that provide habitat for animals and seaweeds.

  • Peat and clay exposures

    Seabeds formed of exposed peat or clay, or in some cases both, which are very rare. Where they do occur they attract a variety of plant and animal life.

Seasearch Logo

Seasearch undertook dives and shore surveys of the area in 2012 in order to provide information for the designation of the site.

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’

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

Over half a million people have voiced their support for ‘marine protected area’ designation in the UK through our campaigns