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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 site has 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 three different colonies around the Irish Sea (Northern Ireland, Wales and Devon) 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 MPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this MPA.

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


The Irish Sea Front 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.


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)


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 Objectives and Reg 18 package – 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.
  • 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 foraging range of 330 km from their colonies (Thaxter et al. 2012); using this range, over 394,000 breeding pairs (from 18 colonies) could potentially travel to this SPA to forage. 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.

Thaxter, C.B., Lascelles, B., Sugar, K., Cook, A.S.C.P., Roos, S., Bolton, M., Langston, R.H.W. & Burton, N.H.K. 2012. Seabird foraging ranges as a preliminary tool for identifying candidate Marine Protected Areas. Biological Conservation, 156, 53–61.

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.



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 three 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 – Two colonies of Manx Shearwater (Copeland, Northern Ireland & Skomer, Wales) have been studied using GPS tracking devices to determine areas the birds visit during the breeding season. During the incubation period, the modelled foraging distributions of individuals from both colonies overlap with the Irish Sea Front SPA (Dean et al. 2012). Another GPS study of a colony on the island of Lundy in 2009 and 2010 also found birds visiting the Irish Sea Front SPA (Dean et al. 2010).
  • 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.

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.


Conservation Advice

Conservation Objectives

The Conservation Objectives set out what needs to be achieved for the site to make the appropriate contribution to the conservation status of the features for which the site is designated and thus deliver the aims of the Birds Directive.

The draft conservation objectives for the protected features of the Irish Sea Front SPA have been set based on our understanding of what is important with regards to defining condition of the protected feature at the time of writing. Further information on conservation objectives is provided in the Irish Sea Front Conservation objectives and advice on operations document.



To avoid significant deterioration of the habitats of 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 Birds Directive for the qualifying species.

This contribution would be achieved through delivering the following objectives for the sites qualifying feature:

  1. Avoid significant mortality, injury and disturbance of the qualifying feature, so that the distribution of the species and ability to use the site are maintained in the long term;
  2. Maintain the habitats and food resources of the qualifying feature in favourable condition.
  3. Ensure access to the site from linked breeding colonies.


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

Conservation Objectives are the starting point from which any management actions and monitoring programmes may be developed and should be considered when completing a Habitats Regulations Appraisal (HRA) for a proposed plan or project in or near this site.


Advice on operations

In line with Regulation (18) of the Offshore Marine Conservation (Natural Habitats, & c.) Regulations 2007 (as amended), the advice on operations identifies those operations (human activities) that may cause damage or deterioration to the qualifying species, or their supporting habitats, for which the Irish Sea Front SPA has been classified. This information will be useful if you are developing, proposing or assessing an activity, plan or project that might affect the site.

The greatest direct threats to Manx shearwater from human activities are likely to be energy production and extraction of living resources (fishing) activities (based on best scientific evidence at the time of writing). However, all may be sensitive to some pressures exerted by the following types of activity;

  • renewable energy developments: wind, wave and tidal.
  • marine hydrocarbon energy developments,
  • fishing activities
  • disturbance from activities such as shipping and recreational boating/yachting.
  • military activities
  • possibly industrial and agricultural liquid discharges and to waste disposal from munitions, but little is known and this is not assessed due to lack of evidence. 

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 package.

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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