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Skomer, Skokholm and the Seas off Pembrokeshire/ Sgomer, Sgogwm a Moroedd Penfro SPA

Status: Special Protection Area (SPA)

Skomer, Skokholm and the Seas off Pembrokeshire SPA / Sgomer, Sgogwm a Moroedd Penfro (hereafter referred to as Skomer, Skokholm and the Seas off Pembrokeshire SPA) is located off the extreme south-west tip of Pembrokeshire in south-west Wales. The islands of Skomer and Skokholm support the largest concentration of breeding seabirds in England and Wales. 


The Skomer, Skokholm and Seas off Pembrokeshire / Sgomer, Sgogwm a Moroedd Penfro SPA (hereafter referred to as Skomer, Skokholm and the Seas off Pembrokeshire SPA) is classified for the protection of: European storm-petrel (Hydrobates pelagicus), Manx shearwater (Puffinus puffinus), Atlantic puffin (Fratercula arctica), and lesser black-backed gull (Larus fuscus), as well as red-billed chough (Pyrrhocorax pyrrhocorax), short-eared owl (Asio flammeus) and breeding seabird assemblage.

Map displaying the Skomer, Skokholm and the Seas off Pembrokeshire MPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this MPA.

Map showing Skomer, Skokholm and the Seas off Pembrokeshire / Sgomer, Sgogwm a Moroedd Penfro Marine Protected Area and linking to the MPA mapper

The islands of Skomer and Skokholm support the largest concentration of breeding seabirds in England and Wales. They hold the largest breeding colony of Manx shearwater in the world (considered to be 316,000 pairs), one of the largest colonies of lesser black-backed gull in Britain (currently over 10,000 apparently occupied sites), as well as being important Welsh breeding sites for other seabird populations, such as razorbill, black-legged kittiwake, Atlantic puffin and common guillemot, supporting a breeding seabird assemblage of over 394,000 birds.

Skomer, Skokholm and the Seas off Pembrokeshire SPA is located off the extreme south-west tip of Pembrokeshire in south-west Wales. This SPA extends beyond the 12 nautical mile boundary, lying partly in Welsh territorial waters and partly in UK offshore waters; therefore both Natural Resources Wales and JNCC have a responsibility to provide statutory advice.

The islands of Skomer, Skokholm and Middleholm are designated as Sites of Special Scientific Interest (SSSI), with Skomer Island also designated as a National Nature Reserve (NNR). The waters immediately around Skomer, are designated as a Marine Conservation Zone (MCZ) and the SPA also overlaps with the Pembrokeshire Marine / Sir Benfro Forol Special Area of Conservation (SAC). The islands of Skomer and Skokholm are one of five UK core seabird monitoring sites under the national Seabird Monitoring Programme (SMP), providing demographic data on numbers, productivity and survival rates.

More detailed site information can be found in the Summary section below.



Legislation behind the designation: The Skomer, Skokholm and the Seas off Pembrokeshire marine Special Protection Area was classified by the UK Government to meet obligations set out in the Birds Directive (2009/147/EC), and is protected by The Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended). Other regulations apply in inshore waters.


Protected Features

Summary of qualifying ornithological features in Skomer, Skokholm and the Seas off Pembrokeshire SPA.

Feature Feature Type % of population1 Conservation objective
European storm petrel
Hydrobates pelagicus
Annex I species (breeding) 4.1% GB
Maintain or Enhance
Red-billed chough
Pyrrhocorax pyrrhocorax
Annex I species (breeding) 1.2% GB Maintain or Enhance
Short-eared owl
Asio flammeus
Annex I species (breeding) 0.6% GB Maintain or Enhance
Manx shearwater
Puffinus puffinus
Regularly occurring migratory species (breeding) 56.9% Global2
(count late 1990s)
Maintain or Enhance
Atlantic puffin
Fratercula arctica
Regularly occurring migratory species (breeding) 1.1% Global
(count late 1990s)
Maintain or Enhance
Lesser black-backed gull
Larus fuscus
Regularly occurring migratory species (breeding) 16.4% of the biogeographical population
(mean 1993–1997)
Maintain or Enhance
Seabird assemblage3 Seabird assemblage of international importance – At least 20,000 seabirds in any season N/A Maintain or Enhance

1Based on data published in Stroud et al. (2001).

2Based on data published in Stroud et al. (2001) and Perrins et al. (2012). Using a new census method suggested a population estimate for Manx shearwater of 316,070 breeding pairs.

3394,260 individuals; the main components are razorbill Alca torda, common guillemot Uria aalge, black-legged kittiwake Rissa tridactyla, Atlantic puffin, lesser black-backed gull, Manx shearwater and European storm petrel.


Conservation Objectives

The overarching conservation objective for the protected features of this site is to ensure that their condition is maintained or enhanced. The ability of a qualifying feature to maintain or enhance its condition can be affected by its sensitivity to pressures associated with activities taking place within or near to a protected site.

Specific information on the conservation objectives relating to this SPA is provided in the Conservation Advice section.


Site Timeline

The diagram below is a summary of the key milestones involved in the selection and classification of the Skomer, Skokholm and the Seas off Pembrokeshire SPA.

August 1982
Skokholm and Skomer SPA classified.
October 2014
Site reclassified and boundary extended to include marine area within a 4 km radius.
January 2016 – May 2016
Formal consultation on boundary extension.
January 2017
Site renamed to Skomer, Skokholm and the Seas off Pembrokeshire SPA and boundary extended.


Relevant Documentation

The documents referred to below and any other historical documents relating to Skomer, Skokholm and the Seas off Pembrokeshire SPA were produced during the selection and classification process and therefore may be out of date. This Site Information Centre is the most up to date source of information for this SPA, and will reflect any additional information gathered since these documents were produced

  • Standard Data Form – provides details about the SPA and the classified features.
  • Departmental briefs:
    • Marine SPA extension (June 2015) – Includes the rationale for the marine SPA extension, and an overview of the qualitfying features.
    • Extension to adjacent waters & findings of 2001 review (Oct 2013) – Rationale for extension to the former Skomer and Skokholm SPA to include adjacent waters, and effect findings of the ‘SPA 2001 review’ (Stroud et al. 2001).
    • Classification of the former Skomer and Skokholm SPA (Aug 1982) – Rationale for the classification of the former Skomer and Skokholm (colony) SPA.
  • Draft Conservation Objectives contains the draft Conservation Objectives for the qualifying bird features of the site.

Information about the general UK SPA site selection process is available on JNCC's SPA webpages.



Last updated November 2017

Site overview

Skomer, Skokholm and the Seas off Pembrokeshire SPA is located off the extreme south-west tip of Pembrokeshire in Welsh territorial and UK offshore waters. It includes the islands of Skomer and Skokholm which hold the largest concentration of breeding seabirds in England and Wales. Especially notable is the population of Manx shearwater Puffinus puffinus which represents the largest breeding colony in the world.

The marine area of the SPA is physically and hydrographically diverse, with high levels of primary productivity. The associated growth and concentration of zooplankton and fish offers rich feeding resources for seabirds and mammals.

The Skomer, Skokholm and the Seas off Pembrokeshire SPA qualifies under Article 4.1 of the Birds Directive, by regularly supporting the Annex I species European storm petrel, red-billed chough and short-eared owl; and qualifies under Article 4.2 by supporting internationally important breeding populations of the regularly occurring migratory species Manx shearwater, Atlantic puffin, and lesser black-backed gull. Furthermore, the Skomer, Skokholm and the Seas off Pembrokeshire SPA protects an assemblage of breeding seabirds (394,260 birds), the listed components of which are Manx shearwater, European storm petrel, Atlantic puffin, black-legged kittiwake, razorbill, common guillemot, and lesser black-backed gull.

Further detail on the evidence for this SPA can be found in the Evidence section.

Site location: the boundary of this SPA can be viewed or downloaded on JNCC's MPA mapper.

Site area: 1,668 km2.

Site depth range: Water depth within the site ranges from mean low water to 50–100 m deep along the seaward boundary of the site.

Charting Progress 2 Biogeographic Region: Western Channel and Celtic Sea.


Site boundary description (timeline)

Skokholm and Smoker SPA was originally classified on 31 August 1982, with an area of 427.7 hectares. Following a public consultation in early 2014, on 7 October 2014, Skokholm and Skomer SPA was reclassified and the boundary extended by a 4 km radius around the islands, adding a marine area of 14,348 ha. The extended boundary included waters vital for essential ecological requirements (preening, bathing, displaying, loafing/resting at sea) for Manx shearwater and Atlantic puffin (as individually qualifying features) as well as common guillemot and razorbill (as component species of the seabird assemblage).

On 30 January 2017, the seaward boundary of the site was extended by 1,524 km2, encompassing two additional marine areas to the south-west of Pembrokeshire, which were identified as hotspots for foraging Manx shearwater, and one area immediately west of Skomer Island, identified as a hotspot for foraging Atlantic puffin.

Information for this site summary was adapted from documents listed in the Relevant Documentation section. More information on the methods used to identify the Skomer, Skokholm and the Seas off Pembrokeshire SPA, can be found in the Evidence section.



Last updated November 2017

Site-specific data

An overview of the data used to support the site identification along with information on qualifying species is available in the Skomer, Skokholm and the Seas off Pembrokeshire SPA Departmental Brief.

Data supporting the classification of this SPA includes breeding seabird colony counts, and boat survey data collated by the European Seabirds at Sea (ESAS) database. Additionally, sea areas around the breeding colonies, important for rafting and maintenance activities, were identified by radio-telemetry surveys. Data from these surveys provide direct evidence confirming the presence of the protected features within the site.

Survey and data gathering

  • European Seabirds At Sea database (1980–2006) – A collation of surveys of seabirds at sea in north-west European waters. The ESAS data analysis showed that more than 66,000 Manx shearwater, and 3,100 Atlantic puffin were present in the marine extension area during their respective breeding seasons. Further information on ESAS and the analytical methods is summarised in marine SPAs for seabirds.
  • Radio telemetry surveys (2003–2005) – These surveys used radio-telemetry to locate key areas used regularly by rafting Manx shearwaters around the three breeding colonies of Skomer (south-west Wales), Rum (western Scotland) and Bardsey (west Wales). They provided evidence to support the delineation of a site-specific seaward boundary extension to protect important rafting areas for Manx shearwater at Skomer and Skokholm SPA, and Rum SPA.
  • Seabird colony counts (2001 review) – Stroud et al. (2001) used colony count data to provide population estimates of breeding seabirds. The 2001 Review figures are a robust and transparently derived baseline dataset, which provides a consistent approach to the UK SPA network. More recent bird count data are also available from a variety of surveillance schemes currently in place.


Data analysis reports

  • Identification of possible marine SPAs for seabirds in the UK (JNCC Report No. 461, 2012) – This report documents a series of analyses used to inform the identification of possible marine Special Protection Areas in the UK based on data from the European Seabirds at Sea database.
  • Seabirds within the British Fishery Limit (JNCC Report No. 431, 2010) – This report documents an analysis of European Seabirds at Sea (ESAS) standardised transect data, undertaken by JNCC, to identify and delineate seabird aggregations within the British Fishery Limit that might qualify as SPAs.
  • Manx shearwater evening rafting behaviour (JNCC Report No. 406, 2008) – This report gives details of a radio-tagging field study (2003–2005) of Manx shearwater breeding colonies in the Skomer and Skokholm SPA, Rum SPA, and Glannau Aberdaron and Ynys Enlli/Aberdaron Coast and Bardsey Island SPA; and presents recommendations in support of setting of site-specific seaward boundary extensions to the three SPAs designated for their internationally important concentrations of Manx shearwaters.

Details of seabird monitoring reports can be found in the Monitoring section.


Additional relevant literature

Please be aware that although these sources contain information which is of interest in relation to this SPA, they do not necessarily represent the views of JNCC:

  • Cook, Aonghais S.C.P., Still, David A., Humphreys, Elizabeth M. & Wright, Lucy J. 2015. Review of evidence for identified seabird aggregations. JNCC Report No. 537. JNCC, Peterborough.
  • Dean, B., Freeman, R., Kirk, H., Leonard, K., Phillips, R.A., Perrins, C.M. & Guilford, T. 2013. Behavioural mapping of a pelagic seabird: combining multiple sensors and a hidden Markov model reveals the distribution of at-sea behaviour. Journal of The Royal Society Interface, 10, 20120570.
  • Perrins, C.M., Wood, M.J., Garroway, C.J., Boyle, D., Oakes, N., Revera, R., Collins, P. & Taylor, C. 2012. A whole-island census of the Manx Shearwaters Puffinus puffinus breeding on Skomer Island in 2011. Seabird, 25, 1–13.
  • Berry, S., Hurford, J., Green, J. & Rogers, A. (eds). 2010. Pembrokeshire Bird Report 2010. The Wildlife Trust South and West Wales, Cardigan.
  • Guilford, T., Meade, J., Willis, J., Phillips, R.A., Boyle, D., Roberts, S. & Perrins, C.M. 2009. Migration and stopover in a small pelagic seabird, the Manx shearwater Puffinus puffinus: insights from machine learning. Proceedings of the Royal Society B: Biological Sciences, 276, 1,215–1,223.
  • WWT Consulting. 2009. Aerial Surveys of Waterbirds in the UK: 2007/08 Final Report. Report to Department of Energy and Climate Change. WWT Consulting, Gloucestershire.
  • Guilford, T.C., Meade, J., Freeman, R., Biro, D., Evans, T., Bonadonna, F., Boyle, D., Roberts, S. & Perrins, C.M. 2008. GPS tracking of the foraging movements of Manx Shearwaters Puffinus puffinus breeding on Skomer Island, Wales. Ibis, 150, 462–473.
  • Smith, S., Thompson, G., & Perrins, C.M. 2001. A census of the Manx Shearwater Puffinus puffinus on Skomer, Skokholm and Middleholm, west Wales. Bird Study, 48(3), 330–340
  • Perrins, C.M. 1991. Skomer Island 1990 & 1991 seabird survival studies, JNCC Report 021, ISSN 0963-8901.
  • Brooke, M. 1990. The Manx shearwater. T & AD Poyser, Academic Press Ltd. London.
  • Harris, M.P. 1972. Inter-Island Movements of Manx Shearwaters. Bird Study, 19(3), 167–171.


Knowledge gaps

If you are aware of any additional data or relevant scientific papers for this site not listed above or in the Relevant Documentation section, please contact us.


Conservation Advice

Last updated: December 2020

Conservation objectives

JNCC and Natural Resources Wales have published joint advice for this SPA within the draft conservation objectives document. Conservation objectives set out the desired state for the protected features of an MPA. The draft conservation objectives for the protected features of the Skomer, Skokholm and the Seas off Pembrokeshire SPA have been set based on knowledge of the condition of the protected features at the time of writing. The conservation objectives for the former Skokholm and Skomer SPA are set out in the core management plan for the SPA published by NRW. These objectives continue to apply, until in due course NRW and JNCC have issued revised 'Regulation 35/18 advice' for the extended/reclassified SPA. This supplementary advice will be posted here when it becomes available.

This information is useful if you are:

  • preparing Habitats Regulations Assessments (HRAs) of proposed plans or projects that may affect the site;
  • planning measures to maintain or enhance the site and its qualifying features;
  • monitoring the condition of the qualifying features; or
  • developing, proposing or assessing an activity, plan or project that may affect the site.

The protected features covered by the draft conservation advice are the qualifying marine species of the SPA: breeding populations of storm petrel, lesser black-backed gull, Manx shearwater, and Atlantic puffin, as well as the breeding seabird assemblage. For each of these features there are four conservation objectives:

  • The size of the population should be stable or increasing, allowing for natural variability, and sustainable in the long term.
  • The distribution of the population should be being maintained, or where appropriate increasing.
  • There should be sufficient habitat, of sufficient quality, to support the population in the long term.
  • Factors affecting the population or its habitat should be under appropriate control.

The feature-specific targets for each of these objectives are provided in the draft conservation objectives document.

Conservation objectives for the qualifying terrestrial species (red-billed chough and short-eared owl) are provided in the core management plan.

Our scientific understanding of the ecology of the site, its integrity, qualifying features and how activities can affect them may change over time. JNCC's and NRW's conservation advice will be kept under review. Conservation advice for sites which straddle the 12 nm boundary will continue to be developed jointly with the relevant country nature conservation body. Further information on JNCC’s conservation advice work is available on its 'Conserving MPAs' webpage. Information can also be found on the Natural Resource Wales website.


Activities and Management

Last updated: December 2020

Management status: Progressing towards being well managed.

Monitoring currently implemented includes compliance with licence conditions, fishing vessel monitoring and condition monitoring of protected features

This site forms part of the network of MPAs across the UK and contributes to international networks such as that of the North-east Atlantic under OSPAR. As the UK is a contracting party to the OSPAR Commission, JNCC is committed to ensuring that the OSPAR MPA network is well-managed.

JNCC considers well-managed to mean the timely progress of an MPA around the 'MPA management cycle'. This involves:

  1. The documentation of appropriate management information – conservation objectives, advice on activities capable of affecting the protected features of a site, and spatial information on the presence and extent of the protected features of a site.
  2. The implementation of management measures – management actions considered necessary to achieve the conservation objectives of a site.
  3. Site condition monitoring programmes – collecting the information necessary to determine progress towards a site's conservation objectives.
  4. Assessment of progress towards conservation objectives – using available information to infer whether or not a site is moving towards or has achieved its conservation objectives.

The sub-sections that follow provide an account of the progress of Skomer, Skokholm and the Seas off Pembrokeshire SPA around each of the four stages in the MPA management cycle:

1. The documentation of appropriate management information

The draft conservation objectives of the protected features of this site are available in the Conservation Advice section.


2. The implementation of management measures

This section details progress towards the implementation of management measures for activities considered capable of affecting the conservation status of the protected feature of the site.

Natural Resources Wales has produced a management plan for the former Skokholm and Skomer SPA. The objectives and measures set out in this plan continue to apply to the re-classified Skomer, Skokholm and the Seas off Pembrokeshire SPA. The plan provides a high-level overview of the objectives for the site, performance indicators, the results of monitoring, and advice on the actions required.

The Standard Data Form lists pressures and threats to which the protected features of the site are considered sensitive. In the marine area, these include the following activities:


  • No site-specific fisheries management measures are currently proposed for this site. A review of the management of fisheries in Welsh waters to ensure compliance with Article 6 of the Habitats Directive is to be carried out by the Welsh Government. Further information will be provided here as it becomes available.
  • Fishing with static demersal gears (gillnets, and pots and traps) occurs within the site, in addition to mobile demersal and mobile pelagic gear.
  • The Skomer, Skokholm and the Seas off Pembrokeshire SPA extends from the coastline beyond the 12 nm limit. Within 6 nm of the coast, only UK vessels are permitted to fish and any management in this area would be implemented by the Inshore Fisheries and Conservation Authorities (IFCAs). Beyond 6nm, the Marine Management Organisation is responsible for fisheries management and compliance.

Licensable activities

  • There are no existing oil and gas licences or marine aggregate licenses in or within 10 km of this area.
  • Licensable activities such as renewable energy developments, aggregate extraction or oil and gas exploration and production taking place or that may take place within this SPA are managed in accordance with The Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended) and The Conservation of Habitats and Species Regulations 2017 (as amended).
  • Existing licensed activities that take place or may take place in the future within the Skomer, Skokholm and the Seas off Pembrokeshire SPA will continue to be managed in line with relevant legislation and application processes by the competent authorities. Further information on JNCC's role in the provision of advice for licensed activities in the UK offshore area is available on JNCC's offshore industry advice webpages.


  • A number of telecommunications cables currently cross through the MPA.
  • Cables are largely an unregulated activity in offshore waters depending upon the type of cable being laid (or maintained), where it is being laid between and whether the cable is part of a larger development (which may be regulated). Any cable not directly associated with an energy installation does not require a marine license beyond 12 nautical miles.
  • JNCC and NRW encourage early discussion from operators regarding any plans related to new or existing cables, and encourages the undertaking of non-statutory environmental impact assessments for new or existing cable projects to assess their effect on the protected features of the MPA.

Shipping and Ports

  • Milford Haven is Wales’ largest port and is in close proximity to the SPA. There are several other smaller ports with quays and jetties close to the SPA.
  • Under international law, ships have a right of passage at sea including in areas designated as MPAs (unless management specifies the restriction of ship transiting as outlined through an International Maritime Organisation measure).
  • Recreational boating also take place near to the site, and includes medium and large sailing vessels, yachts, powerboats and motorboats. Voluntary codes of conduct exist to reduce impacts of recreational activities on MPAs.


3. Site condition monitoring

Information on site condition monitoring is available in the management plan produced for the former Skokholm and Skomer site by Natural Resources Wales.


4. Assessment of progress towards conservation objectives

Further information will be provided in the Assessment section as it becomes available.



Last updated: November 2017

JNCC is currently leading on the development of options for biodiversity monitoring across all UK waters. JNCC’s advice for the monitoring of marine birds, which will include SPA monitoring, is anticipated to contain:

  • A summary of existing monitoring schemes which provide annual trends in abundance and breeding success of seabirds; and trends in the number of waterbirds using coastal sites to breed, stopover on migration or to over-winter; along with options to improve their precision;
  • Options for monitoring and surveillance of inshore and offshore aggregations of seabirds and waterbirds at sea and how these options can best be integrated with the above existing surveillance schemes (including whether coordinated monitoring of the existing/proposed marine SPA network can contribute to these);
  • Integration with indicator development work for Marine Strategy Framework Directive.

Information on monitoring of this SPA will be provided when it becomes available.


Monitoring surveys

  • Seabird numbers and breeding success (2006). This is the eighteenth annual report on the results of seabird monitoring at colonies throughout Britain and Ireland, produced jointly by JNCC, the Royal Society for the Protection of Birds (RSPB) and the Shetland Oil Terminal Environmental Advisory Group (SOTEAG), as part of JNCC's Seabird Monitoring Programme. Data on seabird breeding numbers and breeding success at seabird colonies in 2006 are summarised and compared with results from previous years, primarily 2005, with an analysis of longer term trends in the context of recent findings.
  • Seabird monitoring on Skomer Island in 1999–2002 (JNCC Report No. 339, 2004). This report details the results of seabird monitoring studies on Skomer island in 1999–2002. This includes estimates of breeding population (whole island and plot counts), breeding success, adult and juvenile survival rates, and feeding rates for a variety of breeding seabirds on Skomer Island.



Last updated: December 2020

Under Article 12 of the EU Wild Birds Directive (2009/147/EC), Member States are required to report every six years on their progress on the implementation of the Directive. Following the UK's exit from the European Union, this section will be updated to reflect the new assessment schemes once they are in place.


Published: .

This Site Information Centre (SIC) was created and last substantially updated prior to the end of the Transition Period following the UK’s exit from the European Union (31 December 2020). Therefore some of the content may still refer to EU legislation and management proposals or commitments which were correct at the time that the content was last updated. These references will be revised as necessary when the SIC is next substantially revised. Requirements through EU legislation are being retained in the UK so existing environmental protections and standards remain, and the protection given to habitats and species continues.

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