Annex I Reefs


Annex I reefs occur where rocky areas or concretions made by marine animals arise from the surrounding seafloor. There are three main types of Annex I reef:


  1. Bedrock reef;
  2. Stony reef;
  3. Biogenic reef.


Bedrock and stony reefs are both types of rocky reef. These occur where the bedrock or stable boulders and cobbles arise from the surrounding seabed creating a habitat that is colonised by many different marine animals and plants. Rocky reefs can be very variable in terms of both their structure and the communities that they support. They provide a home to many species such as corals, sponges and sea squirts as well as giving shelter to fish and crustaceans such as lobsters and crabs.


Biogenic reefs are those that are created by the animals themselves. In the UK these include coral reefs, made by cold-water corals such as Lophelia pertusa and Madrepora oculata. Biogenic reefs can also be made by reef-building worms such as the honeycomb worm Sabellaria alveolata, the ross worm Sabellaria spinulosa and the serpulid worm Serpula vermicularis. Mussels such as the edible mussel Mytilus edulis and the horse mussel Modiolus modiolus can also create biogenic reef structures. In UK offshore waters the main types of biogenic reef that JNCC are looking to identify additional SACs for are cold-water coral reefs, Sabellaria spinulosa reefs and Modiolus modiolus reefs. Examples of what the different types of Annex I reefs can look like can be seen in the gallery below.





SACs have been selected in UK waters for reef habitats to ensure that we have included the full range of different reef types in the SAC network - from bedrock and stony reef through to the different types of biogenic reef. Reefs occur throughout UK waters, from the English Channel to far off north-west Scotland, and the animals and plants the reefs support vary in these different areas mainly as a result of differences in temperatures. SACs are also selected to ensure that reef habitats are protected throughout the full geographical range in which they occur.


JNCC maintain a map that shows areas of potential Annex I reef in UK offshore waters. These are areas where JNCC believe, from the best available evidence, that Annex I reef might be present. Through offshore survey, JNCC is working to confirm the presence of Annex I reef in these areas. For information on the identification of Annex I reef SACs within 12 nautical miles of the coast, please contact the relevant country conservation agency.


Further reading

Official definition
Sabellaria spinulosa reefs:
  • In May 2007 JNCC held a workshop on "Defining and managing Sabellaria spinulosa reefs". The report produced following the workshop is available on the JNCC website. JNCC Report 405.
Stony reefs:
  • In March 2008 JNCC held a workshop on "The identification of the main characteristics of stony reef" to better define a stony reef. The report produced following the workshop is available on the JNCC website. JNCC Report 432.