Blue rayed limpets on kelp

What’s special?

The Pembrokeshire Marine SAC was selected as containing excellent European examples of the following ‘conservation features’. Conservation, or interest, features are the habitats and species for which a site is designated. The Pembrokeshire Marine site is particularly diverse, with eight Habitats Directive Annex I habitat types and seven Annex II species (almost the longest list of any marine SAC in the UK).

These are:

Large shallow inlets and bays
Mud and sand flats
Subtidal sandbanks
Atlantic salt meadow

Grey Seals
Sea & River Lampreys
Allis & Twaite Shads
Shore dock

A short description of each conservation feature is below. For more detail visit the individual page.

Natural Resources Wales (NRW) gather information about these features of the site to build our understanding of how they are doing and help to identify and address any pressures or threats they may be facing. Some reports can be found at Natural Resources Wales / Marine and coastal evidence reports.

This information helps with feature condition assessment reporting (see Progress).

Gathering data underwater is of course more difficult than looking around on land. Even knowing what is where is a challenge. An indication of where these features are within the site can be seen at Pembrokeshire Marine non-interactive A3 map (

Kelpforest and understory


As well as extensive areas of underwater rocky reef stretching offshore from the wild open coast, rocky reefs can also be found throughout the more sheltered environment of the Milford Haven waterway. And intertidal reefs make for good rock pooling!


Estuaries are coastal inlets where there is generally a large freshwater influence. They are made up of many different habitat types and are influenced by the tide.

Large shallow inlets & bays

Large shallow inlets and bays are usually large indentations of the coast that are generally more sheltered from wave action than the open coast and are relatively shallow, usually averaging less than 30m in depth.

Empty Tellin shell on the beach (Sue Burton)

Mud & sand flats

Sandy beaches on the open coast and mudflats in sheltered areas contain many and varied species, mostly hidden from sight below the surface.

Plaice hidden in sand (Rohan Holt at CloudBase Productions Ltd)

Subtidal sandbanks

Sandy areas of seabed permanently covered by shallow sea water are home to rich communities of animals. They can be important nursery areas for fish and feeding grounds for seabirds.

Saltmarsh plant (John Archer-Thomson)

Atlantic salt meadow

Atlantic salt meadows form the middle and upper reaches of salt marshes, where the vegetation is still covered by the tide but less often and for shorter times.

Spiny cockle (Sue Burton)


Lagoons are expanses of shallow coastal salt water, of varying salinity and water volume, wholly or partially cut off from the sea by sandbanks or shingle, or, less frequently, by rocks.

Baked bean sea squirts (Rohan Holt at CloudBase Productions Ltd)


Sea caves are formed where the specific geology of an area allows for the weathering and erosion of material to create overhangs, clefts, caves and tunnels.

Grey seal female at waters edge (Kate Lock - Natural resources Wales)

Grey seals

Grey seals are one of the least common seal species in the world. They can be found within the site throughout the year. White coated pups are born around August to December.

Otter (Jonathan Barker)


Otters are not just riverine mammals. They forage in the sea all around the Pembrokeshire coast.

Lamprey Annalisa 2 (John Archer-Thomson

Sea & river lampreys

Lampreys are a primitive type of fish that have a distinctive suckered mouth rather than jaws, quite unlike any other fish in the UK.

Twaite shad

Allis & twaite shads

Shad are herring-like fish that spend most of their adult lives in the sea but are born and reproduce in rivers (or, occasionally, in the upper reaches of estuaries).

Shore dock

Shore dock is one of Europe’s most threatened endemic vascular plants. The UK is the world stronghold for this species. Shore dock is currently known to occur in only one site within the SAC.