Carmarthen Bay and Estuaries/ Bae Caerfyrddin ac Aberoedd

General site character

• Marine areas, Sea inlets (82.1%)
  
• Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (13.7%)
  
• Salt marshes, Salt pastures, Salt steppes (4.1%)
  
• Shingle, Sea cliffs, Islets (0.1%)
  

Annex I habitats that are a primary reason for selection of this site

• 1110 Sandbanks which are slightly covered by sea water all the time

  Carmarthen Bay and Estuaries on the south coast of Wales includes the sandbank of Helwick Bank, a linear shallow subtidal sandbank that is unusual in being highly exposed to wave and tidal action. The animal communities found in and on the bank reflect these conditions, being tolerant of high levels of disturbance. Within Carmarthen Bay there are also several other smaller sandbanks in relatively shallow waters, which support a range of species (including bivalves, amphipods and worms), many of which spend most of their time wholly or partly buried in the sediment.

• 1130 Estuaries

  Carmarthen Bay and Estuaries provides an example of a large estuarine site on the south coast of Wales, encompassing the estuaries of the Rivers Loughor, Tâf and Tywi (coastal plain estuaries) and the Gwendraeth (a bar-built estuary). These four estuaries form a single functional unit around the Burry Inlet, with important interchanges of sediment and biota. The estuaries of this site support a range of subtidal and intertidal sediments that grade from sand at the mouth to mudflats in the upper estuary. The fauna of the sediments varies, but includes communities with polychaete and oligochaete worms and areas with extensive cockle beds and other bivalve molluscs. This site has a range of undisturbed transitions to coastal habitats.

• 1140 Mudflats and sandflats not covered by seawater at low tide

  Carmarthen Bay and Estuaries on the south coast of Wales includes extensive areas of intertidal mudflats and sandflats. Large areas of these intertidal flats are dominated by bivalves. In areas of fine sand cockles Cerastoderma edule are abundant, along with other bivalves, amphipods and worms. In muddier sediments the sand-gaper Mya arenaria, peppery furrow-shell Scrobicularia plana and mud-snail Hydrobia ulvae are also found in large numbers. The lower Loughor Estuary is one of the few places in the UK where the worm Ophelia bicornis has been found. There are also beds of the nationally scarce dwarf eelgrass Zostera noltei.

• 1160 Large shallow inlets and bays

  Carmarthen Bay, off the south Wales coast is an extensive shallow bay. Throughout the bay physical conditions vary considerably. Salinity varies from low (at the estuaries) to fully marine, there are gradients in wave action from sheltered to exposed, and strong tides sweep exposed headlands whilst other areas are sheltered from currents. There is a wide range of seabed types, including mud, sand and rock, although the majority of the seabed is sandy. The sediment supports a large number of species, including bivalve molluscs, worms, burrowing urchins, brittlestars and sand-stars.

• 1310 Salicornia and other annuals colonizing mud and sand

  Carmarthen Bay and Estuaries in south Wales is selected as representative of pioneer glasswort Salicornia spp. saltmarsh in the south-west of the UK. It forms an integral part of the estuarine system, supporting extensive pioneer communities and contributing to a complete sequence of saltmarsh vegetation, including transitions to upper saltmeadow and to important sand dune habitats.

• 1330 Atlantic salt meadows (Glauco-Puccinellietalia maritimae)

  This extensive site in south Wales has a complete sequence of saltmarsh vegetation, from pioneer vegetation through to upper saltmarsh transitions. The grazed saltmarshes include upper margins with sea rush Juncus maritimus and marsh-mallow Althaea officinalis, which are a particularly distinctive ecological feature of this site. The area is also important for transitions from saltmarsh to sand dune and other habitats.

Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site

• Not Applicable

Annex II species that are a primary reason for selection of this site

• 1103 Twaite shad Alosa fallax

  Twaite shad Alosa fallax migrate though the waters of Carmarthen Bay and Estuaries cSAC to reach spawning sites in the Afon Tywi. The Taf-Tywi-Gwendraeth estuary is also an important nursery area for juveniles and it is likely that twaite shad feed in the inshore waters of Carmarthen Bay.

Annex II species present as a qualifying feature, but not a primary reason for site selection

• 1095 Sea lamprey Petromyzon marinus
• 1099 River lamprey Lampetra fluviatilis
• 1102 Allis shad Alosa alosa
• 1355 Otter Lutra lutra