Southern North Sea MPA


Status: Candidate Special Area of Conservation (cSAC)


The Southern North Sea cSAC has been identified as an area of importance for harbour porpoise. This site includes key winter and summer habitat for this species and covers an area over 3 times the size of Yorkshire, making it the largest cSAC in UK and European waters at the point of designation in 2017.


Located to the east of England, this site stretches from the central North Sea (north of Dogger Bank) to the Straits of Dover in the south, covering an area of 36 951km2. The majority of this site lies offshore, though it does extend into coastal areas of Norfolk and Suffolk crossing the 12 nautical mile boundary and hence, both Natural England and JNCC are responsible for providing statutory advice. A mix of habitats, such as sandbanks and gravel beds, are included in

the site and water depths range from Mean Low Water (MLW) to 75m,

with the majority of the site shallower than 40m.

More detailed site information can be found on the Summary tab below.


Southern North Sea boundary map.

This image will link to the MPA mapper and boundary downloads in due course


Legislation behind the designation: EU Habitats Directive 1992 transposed into UK law by the Conservation of Habitats and Species Regulations 2010 (as amended) within 12 nautical miles (nm), and the Offshore Marine Conservation (Natural Habitats &c.) Regulations 2007 (as amended) between 12nm out to 200nm or the UK Continental Shelf.


Protected Features:

Features Feature Type % of population Conservation Objectives

Harbour porpoise

Phocoena phocoena

        Annex II Species        

17.5% of the North Sea

Management Unit

Maintain site integrity


Conservation Objectives

To avoid deterioration of the habitats of the harbour porpoise or significant disturbance to the harbour porpoise, thus ensuring that the integrity of the site is maintained and the site makes an appropriate contribution to maintaining Favourable Conservation Status for the UK harbour porpoise.

Site Timeline

The bullets below are a summary of the key milestones involved in the selection and designation of the Southern North Sea cSAC.  More detail can be found within the relevant documentation listed below.

  • December 2014: site submitted as initial advice to Government
  • June 2015: Site formally recommended to UK Government as a draft SAC (dSAC)
  • January - May 2016: Formal public consultation - site becomes a possible SAC (pSAC)
  • September 2016: post consultation advice submitted to UK Government
  • January 2017: Site submitted to the European Commission - site becomes a candidate SAC (cSAC)


Relevant documentation

Some documents relating to the Southern North Sea cSAC were produced during the selection and designation process and therefore may be out of date.  This Site Information Centre is the most up to date source of information for this site and will reflect any additional information gathered since these documents were produced.


Information about the SAC site selection process is available on the JNCC SAC pages.



Site overview
The Southern North Sea cSAC lies along the east coast of England, predominantly in the offshore waters of the central and southern North Sea, from north of Dogger Bank to the Straits of Dover in the south. It covers an area of 36 951 km2, designated for the protection of harbour porpoise Phocoena phocoena. This area supports an estimated 17.5% of the UK North Sea Management Unit (MU) population. Approximately two thirds of the site, the northern part, is recognised as important for porpoises during the summer season, whilst the southern part support persistently higher densities during the winter.

The cSAC ranges in depth from Mean Low Water down to 75m, with the majority of the site shallower than 40m, and is characterised by its sandy, coarse sediments which cover much of the site. These physical characteristics are thought to be preferred by harbour porpoise, likely due to availability of prey.

Survey data collated through the Joint Cetacean Protocol (JCP) were further analysed to identify areas with persistently high harbour porpoise occurrence. The modelled outputs of this analysis demonstrate that the Southern North Sea cSAC persistently contains densities of porpoises which are within the top 10% of those for the Management Unit in both winter and summer seasons.


Site location:  The boundary of this cSAC will be available to view and download via the JNCC MPA Mapper. Coordinates for this cSAC are available from the Standard Data Form (SDF) listed in the Relevant Documentation.

Site area:  This site has an area of 36, 951km2

Site depth range: The site ranges from Mean Low Water to 75m below sea level.

Charting Progress 2 Biogeographic Region:  Southern North Sea and Northern North Sea regions

Site boundary description
The Southern North Sea cSAC boundary was defined based on predicted areas with high densities of harbour porpoise identified through data modelling over an 18-year period. As a general principle, site boundaries were drawn tightly around the qualifying feature. The seaward boundaries were drawn using straight lines where possible; however, a balance was needed between more-complex site shapes drawn tightly around the feature and simple square/rectangular boundaries, so that the area of ‘non-interest-feature’ within the boundary was reduced. Further boundary principles were developed due to the nature of the modelled output. The modelling approach used 5 x 5 km grids, and so the model output was “blocky”, and further boundary smoothing methods were applied to simplify the boundary, without altering the site area by more than 5%. Coastal edges were defined by the “Mean Low Water” (MLW) tide line.

The information for this site summary was adapted from documents listed in the Relevant Documentation section and incorporates any further information gathered since these documents were produced.


Detail available soon.



Detail available soon.



Detail available soon.



Detail available soon.



Detail available soon.




Return to Graphics version

| JNCC - Adviser to Government on Nature Conservation | Site Map | Search | Legal | Feedback | List Access Keys |