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Irish Sea Front SPA

Status: Special Protection Area (SPA)

The Irish Sea SPA lies in the Irish Sea, about 35 km south-west of the Isle of Man and 36 km to the north-west of Anglesey, the boundaries of the site are beyond 12 nautical miles and entirely within offshore waters; therefore JNCC has sole responsibility to provide statutory advice. The site was classified for its importance as a foraging site for Manx shearwaters, hosting the third largest marine aggregation of breeding Manx shearwaters identified in the UK.


Located in the Irish Sea, about 35 km south-west of the Isle of Man and 36 km to the north-west of Anglesey, the Irish Sea SPA is known to regularly support a population of European importance for Manx shearwater (Puffinus puffinus), which are likely to use the area as a foraging location during the breeding season.

The Irish Sea Front SPA is the third largest marine aggregation of breeding Manx shearwaters identified in the UK (Kober et al., 2012). Data from the extensive European Seabirds at Sea (ESAS) database suggest that more than 12,000 Manx Shearwater could be present in the area. Tracking studies indicate that Manx shearwaters from at least six different colonies around the Irish and Celtic Seas (Copeland, Rum, Bardsey, Skomer, Skokholm and Lundy) are likely to use the Irish Sea Front SPA for foraging during the breeding season.

This site is located over part of a large tidal front which forms in the spring every year. This tidal front creates an area of very productive sea, with high concentrations of zooplankton leading to large numbers of prey species contributing to the sites importance.

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


Map displaying the Irish Sea Front SPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this SPA.

Map showing Irish Sea Front Marine Protected Area and linking to the MPA mapper


The Irish Sea Front (ISF) SPA was classified in 2017 under the Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended) for its importance as a foraging location for Manx shearwaters listed in Annex 1 of the EU Birds Directive (2009/147/EC). Post EU-Exit these regulations have been superseded by The Conservation of Habitats and Species (Amendment) (EU Exit) Regulations 2019 which ensure that the habitat and species protection and standards derived from EU law continue to apply.

Site details

Region UK offshore waters, Irish Sea
Location (Centroid*) 53° 41.53’ N 5° 2.725’ W
Area 180 km2
Feature Manx shearwater (Puffinus puffinus)


Site timeline

Irish Sea Front SPA site classified
Irish Sea Front SPA conservation advice published


Relevant Documents

The documents referred to below are specific to the Irish Sea Front SPA and form JNCC’s advice and evidence package. 

  • Departmental Brief – This document is a detailed overview of the SPA, the qualifying features and rationale for site selection.
  • Conservation Advice and Advice on Operations – This document contains the draft Conservation Objectives for the qualifying bird features of the site as well as information about the sensitivity of the features to human activities and their pressures on the environment.
  • Advice on Operations spreadsheet - This spreadsheet provides information on the activities capable of affecting site integrity and therefore achievement of the site’s conservation objectives.
  • Management Options Paper – This paper considers a range of activities taking place within the SPA, and focuses on those activities which we consider present a risk to the protected features.
  • Screening document – This document contains a brief assessment of human activities which take place at or close by the SPA, and which could have a negative impact on the feature of interest, the supporting habitats and their structure, functioning and supporting processes. It describes what management could look like under different management scenarios and provides a brief estimate of the socio-economic costs of the classification of the site and the subsequent potential management.

These resources are available on JNCC's Resource Hub

Information about the general UK SPA site selection process is available on JNCC's SPA webpages. Details about how JNCC selected the most suitable pSPAs in UK offshore waters (Stage 2 of the UK SPA selection process) is provided in an accompanying document.



Site overview

The Irish Sea Front is an area of the Irish Sea between Anglesey and the Isle of Man; it covers an area 180 km2. The area is a Special Protection Area for the Manx shearwater.

Within the site a tidal-mixing front occurs every spring and lasts through to late summer (Simpson and Hunter 1974). Fronts such as this are known to aggregate high numbers of marine organisms, making feeding profitable for species such as shearwaters (Vlietstra et al. 2005). This front contains the highest density of zooplankton within the western Irish Sea (Scrope-Howe and Jones 1985) and high numbers of herring are thought to aggregate in this area in response to the thermal and salinity gradients (Schneider 1990).

Bathymetry changes rapidly within the site and small 'trenches' in the seabed stretch from the south-west to the north-east. Water depths range between 45 m at the eastern limit of the site down to 80 m at the southern limit. The combined effect of currents and waves creates a moderate-energy seabed environment, comprised of either coarse sediments or sand and muddy sand (McBreen et al. 2011)

The site was identified as a hotspot of seabirds based on data from the European Seabirds At Sea database (ESAS). The analysis of ESAS data estimated a modelled population of over 12,000 Manx shearwaters within the Irish Sea Front SPA during the breeding season. Manx shearwaters have a mean maximum foraging range of 1346.8km (±1018.7km) from their colonies (Woodward et al. 2019); using this range Manx shearwaters breeding at all UK colonies (57 colonies counted during Seabird 2000) could potentially travel to this SPA to forage. The most recent population counts from colonies with known links to the Irish Sea Front region suggest that over 500,000 breeding pairs (from 6 colonies) could potentially use this SPA. This highlights the potential significance of the SPA as a foraging area for the Manx shearwater breeding population across the Irish Sea region.

More details of these studies can be found in the Evidence section.

Site boundary description: The boundary of the Irish Sea Front SPA is based on the extent of the important aggregation of Manx shearwaters identified through analysis of available data. The boundary is drawn around gridded density data and is completely offshore with no landmass within its boundary. Further information about the methods used to identify the Irish Sea Front SPA is available on our SPAs webpages, or in the report on ESAS methods, which will provide more details on the data and methods used for this work.



McBreen, F., Askew, N., Cameron, A., Connor, D., Ellwood, H. & Carter, A. 2011. UKSeaMap 2010: Predictive mapping of seabed habitats in UK waters. JNCC Report No. 446.

Schneider, D.C. 1990. Seabirds and fronts: a brief overview. Polar Research, 8, 17–21.

Scrope-Howe, S. & Jones, D.A. 1985. Biological studies in the vicinity of a shallow-sea tidal mixing front. V. Composition, abundance and distribution of zooplankton in the western Irish Sea, April 1980 to November 1981. Philosophical Transactions of the Royal Society of London Series B, 310, 501–519.

Simpson, J.H. & Hunter, J.R. 1974. Fronts in the Irish Sea. Nature, 250, 404–406.

Vlietstra, L.S., Coyle, K.O., Kachel, N.B. & Hunt, G.L. 2005. Tidal front affects the size of prey used by a top marine predator, the short-tailed shearwater (Puffinus tenuirostris). Fisheries Oceanography, 14, 196–211.

Woodward, I., Thaxter, C., Owen, E. and Cook, A., 2019. Desk-based revision of seabird foraging ranges used for HRA screening. BTO.



Site-specific data

The full overview of the data used to support site identification along with information on qualifying species is available in the Irish Sea Front SPA Departmental Brief.

Data for the identification of this SPA have been collected by boat surveys for the ESAS database. Data from these surveys provide direct evidence confirming the presence of the protected features within this area. Evidence from further boat surveys support the findings of the ESAS analysis and provide an independent analysis on more recent data that indicates the bird populations recorded for the Irish Sea Front SPA in the ESAS database are likely to be present in more recent years. Tracking studies indicate that breeding Manx shearwaters from at least six different colonies around the Irish Sea are likely to use the Irish Sea Front SPA to forage and highlight the potential significance of the area. Information from the seabird colony counts is used to supplement ESAS data to provide evidence of regular occurrence of species at colonies which are most likely to provide birds that forage in the Irish Sea Front SPA.


Data gathering

  • European Seabirds at Sea database – The European Seabirds at Sea (ESAS) database is a collation of surveys of seabirds at sea in north-west European waters. Further information on ESAS and the analytical methods is summarised in marine SPAs for seabirds. The analysis of 25 years of ESAS data estimated a modelled population of 12,039 Manx shearwaters (based on spatial interpolation, whilst a precise figure is quoted it should only be considered an indication of the population) using the Irish Sea Front SPA during the breeding season. This figure is equivalent to more than 1% of the biogeographic population (Mitchell et al. 2004), therefore meeting the threshold under the UK SPA selection guidance. However this population value was only recorded in 3 out of 5 years, so the criterion of 'regularity' set in the selection guidelines was not met. The area was therefore assessed under Stage 1.4 of the UK SPA selection guidelines.  In the Stage 2 assessment of all possible SPAs the Irish Sea Front was selected as one of the most suitable areas for classification, further details on this can be found in the Application of Stage 2 document.
  • Centrica Energy 2012 – Data analysis from Centrica Energy boat surveys (Centrica, 2012), carried out in 2010–2011, also supports the findings within the ESAS data that Manx Shearwaters are present in high densities within the Irish Sea Front SPA. This independent analysis confirms that the birds continue to be present in more recent years.
  • Tracking Surveys – six colonies of Manx Shearwater (Copeland, Northern Ireland; Skomer, Skokholm & Bardsey, Wales; Rum, Scotland and Lundy, England) have been studied using GPS tracking devices to determine areas the birds visit during the breeding season. During the breeding season the Irish Sea Front region was shown to be a key shared foraging location for shearwaters from four colonies (Rum, Copeland, Skomer and Lundy)(Dean et al. 2015). Bardsey Island tracking data, available on the Seabird Tracking Database shows birds using the region.
  • Linked Colonies – Census data available from 1969-70, 1985-88 and 1998–2002 for Manx shearwaters from three colonies (Skomer and Skokholm SPA, the Lundy colony and the Copeland colony) shows the birds using the Irish Sea Front SPA.



European Seabirds at Sea (ESAS) database

Centrica Energy. 2012. Irish Sea Zone: Zonal Appraisal and Planning (ZAP) Report.

Dean, B., Freeman, R., Kirk, H. & Guildford,T. 2010. Tracking the movements of Lundy's shearwaters. Annual Report of the Lundy Field Society, No. 60, part 20.

Dean, B., Freeman, R., Kirk, K., Leonard, K., Phillips, R.A., Perrins, C.M. & Guildford, T. 2012. 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.

Dean, B., Kirk, H., Fayet, A., Shoji, A., Freeman, R., Leonard, K., Perrins, C.M. and Guilford, T., 2015. Simultaneous multi-colony tracking of a pelagic seabird reveals cross-colony utilization of a shared foraging area. Marine Ecology Progress Series538, pp.239-248.

Mitchell, P.I., Newton, S.F., Ratcliffe, N. & Dunn, T.E. 2004. Seabird populations of Britain and Ireland. Results of the Seabird 2000 census.  T & A.D Poyser, London.

Seabird Tracking Database 


Conservation Advice

Conservation Objectives

The role of the Conservation Objectives is to ensure that the obligations of the relevant Habitats Regulations are met by ensuring the integrity of the site is maintained, and that the qualifying feature, Manx shearwater, makes an appropriate contribution to favourable conservation status (FCS) at the national level and contributes to the UK Marine Strategy vision of “clean, healthy, safe, productive and biologically diverse oceans and seas”.

The Conservation Objectives seek to maintain the protected SPA feature where evidence exists that the feature is in favourable condition in the site, or where there is uncertainty concerning the assessed condition of the feature but no reason to suspect deterioration in condition since classification.

Site conservation objective:

To avoid significant deterioration of the habitats used by the qualifying species, or significant disturbance to the qualifying species, subject to natural change, thus ensuring that the integrity of the site is maintained in the long term and makes an appropriate contribution to achieving the aims of the Conservation of Habitats and Species Regulations 2017.

This contribution would be achieved through delivering the following objectives for the site’s qualifying feature:  

  1. Avoid significant disturbance of the qualifying feature within the site, so that the ability of the species to use the site is maintained in the long-term;
  2. Maintain the habitats, processes and food resources of the qualifying feature in favourable condition;
  3. Ensure connectivity between the site and its supporting habitats and Manx shearwater breeding colonies is maintained.

Further supplementary advice on the conservation objectives is provided in the Conservation Objectives and advice on operations document.

Conservation Objectives provide the basis for advice on any site-based conservation or management measures and inform the consideration of whether plans and projects are likely to have significant effect on the site; the scope and conclusions of appropriate assessments; and the determination of whether plans or projects will adversely affect the integrity of the site. Advice should be referred to if you:

  • undertake Habitat Regulations Assessments (HRAs) to identify and assess the potential impacts of plans or projects that could impact the site;
  • provide information for an HRA;
  • respond to specific measures to support delivery of the conservation objectives for the site; and
  • consider the need to put new or additional management measures in place.

Advice on operations

The Advice on Operations identifies operations (human activities) that may cause damage or deterioration of the qualifying species for which the site has been classified or of their supporting habitats. The aim of this advice is to enable the competent/relevant authorities and practitioners to conduct and prioritise the management of activities within and outside of the site in order to reduce/minimise the potential threat to Manx shearwaters within the SPA.

Manx shearwater is thought to be sensitive to a number of direct and indirect pressures at sea which can be exerted by a number of activities:

  • Extraction of living resources
  • Extraction of non-living resources
  • Energy generation (renewable and hydrocarbon)
  • Transport (shipping)
  • Recreation and leisure
  • Defence and national security
  • Waste management
  • Other man-made structures
  • Research

These activities do not necessarily occur in or near the site at present however they are important to bear in mind to avoid potentially damaging activities from occurring within the SPA in the future.

Any activity that can cause a pressure or pressures to which the feature may be sensitive could present a risk to the feature of not achieving the conservation objective and we advise competent authorities should manage these in order to reduce or remove the overall risk to the proposed site’s qualifying features. Further information on activities than can present a risk to the achievement of the site’s conservation objectives is available in the advice on operations spreadsheet.

Our scientific understanding of the ecology of the site, its integrity and its qualifying features and how activities can affect them may change over time. JNCC’s conservation advice will be kept under review and will be periodically updated to reflect this.



Management actions seek to avoid any adverse effects on the listed features from those pressures associated with human activities.  All activities (on or off-site) should be managed in such a way as to minimise disturbance and mortality of the proposed bird features themselves or the habitat and food resource on which they rely, to avoid the risk of impacting the local population level to ensure the site’s conservation objectives are achieved (Tillin et al. 2010).

JNCC has developed a management options paper to support discussions with stakeholders about the management of activities within this SPA. This paper considers a range of activities and developments taking place within the SPA at the point of writing, and focuses on where we consider there could be a risk of the protected features not achieving their conservation objectives.   



Tillin, H.M., Hull, S.C. & Tyler-Walters, H. 2010. Development of a Sensitivity Matrix (pressures-MCZ/MPA features). Report to the Department of Environment, Food and Rural Affairs from ABPMer, Southampton and the Marine Life Information Network (MarLIN) Plymouth: Marine Biological Association of the UK. Defra Contract No. MB0102 Task 3A, Report No. 22.a.


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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