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Special Areas of Conservation

Y Fenai a Bae Conwy/ Menai Strait and Conwy Bay

Designated Special Area of Conservation (SAC)
Country Wales
Unitary Authority Extra-Regio, West Wales and The Valleys
Centroid* SH629728
Latitude 53.23444444
Longitude -4.055
SAC EU Code UK0030202
Status Designated Special Area of Conservation (SAC)
Area (ha) 26501.64
* This is the approximate central point of the SAC. In the case of large, linear or composite sites, this may not represent the location where a feature occurs within the SAC.
Location of Y Fenai a Bae Conwy/ Menai Strait and Conwy Bay SAC

General site character

  • Marine areas, Sea inlets (80%)
  • Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (19%)
  • Salt marshes, Salt pastures, Salt steppes (0.5%)
  • Shingle, Sea cliffs, Islets (0.5%)

Download the Standard Data Form for this site as submitted to Europe (PDF <100kb)

Note When undertaking an appropriate assessment of impacts at a site, all features of European importance (both primary and non-primary) need to be considered.

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

  • Menai Strait and Conwy Bay between mainland Wales and Anglesey includes the Four Fathom Banks complex, which is a relatively rare type of subtidal sandbank in Wales, in that it is comparatively large, and is fairly sheltered from wave action but situated in an area of open coast. The sandbanks vary from stable muddy sands in areas that experience weak tidal streams to relatively clean well-sorted and rippled sand in the outer area of the bank where tidal streams are stronger. In very shallow waters, particularly in the inner shore areas, relatively species-rich sandy communities are dominated by polychaetes such as Spio filicornis. In some years when numbers of bivalves are high, internationally important flocks of common scoter Melanitta nigra have been observed to congregate in the area of the Four Fathom Banks complex to feed.

  • The intertidal mudflats and sandflats of the Menai Strait and Conwy Bay on the north Wales coast include Traeth Lafan, the shores of the Menai Strait, and the Foryd estuary. Traeth Lafan is an example of an almost fully marine extensive mud and sandflat that experiences a broad range of wave exposure, providing a range of sediment types with typical associated communities. For example, the shrimps Haustorius arenarius and Bathyporeia sarsi are found in mobile clean sand, whilst bivalves such as the cockle Cerastoderma edule, the gaper Mya arenaria and Baltic tellin Macoma balthica are common in more sheltered fine and muddy sand. The sand-mason worm Lanice conchilega is found in more tide-swept areas. The mixed sediment shores between Beaumaris and Lleiniog are highly productive shores that are rich in animal and plant species. These shores include a nationally important biotope that is rare in the UK. The nationally scarce dwarf eelgrass Zostera noltei is also found at this site.

  • 1170 Reefs

    The reefs of the Menai Strait and Conwy Bay between mainland Wales and Anglesey include the tidal rapids of the Menai Strait, and limestone reefs along the south-east Anglesey coast and around Puffin Island and the Great and Little Ormes. The environmental conditions of the Menai Strait are unusual. The water is relatively turbid, containing a relatively high level of suspended material, and although the area is largely sheltered from wave action tidal streams are strong, reaching up to 8 knots (4 m s-1) in places during spring tides. As a result, the rocky reefs of the Strait are dominated by a diverse and unusual mixture of animals that feed mainly by filtering their food from the seawater. For example, colonies of sponges, such as the breadcrumb sponge Halichondria panicea, grow to unusually large sizes, with single colonies covering areas of over 1 m2. The limestone reefs are home to several species that bore into rock, and some limestone specialists are restricted to this relatively rare habitat. Species include the rock-boring sponge Cliona celata, piddocks Hiatella arctica, polychaete worms Polydora sp., and acorn worms Phoronis hippocrepia.

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

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

  • Not Applicable

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

  • Not Applicable

Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.