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Pisces Reef Complex MPA

Status: Special Area of Conservation (SAC)

The Pisces Reef Complex is located in the western Irish Sea, in the north-west mud basin. It is approximately midway between the Isle of Man and the coast of Northern Ireland.


Located in the western Irish Sea, in the north-west mud basin, the Pisces Reef Complex is approximately midway between the Isle of Man and the coast of Northern Ireland.

The site has an extensive mud plain with three protruding areas of Annex I bedrock and boulder-dominated stony reef. The three reefs rise 15–35 m above the seabed and are composed of silty bedrock, with a patchy veneer of muddy sediment, due to sediment deposition from a localised scouring process. The reefs themselves support a diverse community of brachiopods, ascidians, hydroids, sponges and fish. The Pisces Reef Complex MPA overlaps with a Special Area of Conservation that has been identified for the protection of Harbour porpoise, the North Channel MPA.

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


Map displaying the Pisces Reef Complex MPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this MPA.

Map showing Pisces Reef Complex Marine Protected Area and linking to the MPA mapper


Legislation behind the designation: EU Habitats Directive 1992 transposed into UK law by the Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended).


Protected Features

Feature Feature Type
1170 reefs Annex 1 Habitat


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

The acquisition of new data may result in updates to our knowledge on feature presence and extent within this site. The most up-to-date information is reflected on the map on this page and in JNCC’s MPA Mapper and the evidence underpinning this can be viewed in the Monitoring and Evidence section.


Site Timeline

The diagram below is a summary of the key milestones involved in the selection and designation of Pisces Reef Complex SAC. More detail can be found in the Relevant Documentation section.

May 2012
Site formally recommended to the UK Government as a draft Special Area of Conservation (SAC).
August 2012
Site becomes a candidate SAC (cSAC) and is entered on the Register of European Marine Sites.
November 2013
Site is approved by the European Commission as a Site of Community Importance (SCI).
January 2015
Management measures proposal submitted to the Commission.
September 2017
Site is formally designated as a SAC by UK Government.


Relevant Documentation

The documents referred to below and any other historical documents relating to Pisces Reef Complex SAC 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 MPA, and will reflect any additional information gathered since these documents were produced. Information about the SAC site selection process is available on JNCC's SAC webpages.

These resources are available on JNCC's Resource Hub.



Last updated: October 2017

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. Please refer to the relevant documentation section for further details and information sources.


Site overview

The Pisces Reef Complex is located in the western Irish Sea, in the north-west mud basin. It is approximately midway between the Isle of Man and the coast of Northern Ireland. The area consists of an extensive mud plain through which three areas of Annex I bedrock and boulder-dominated stony reef protrude. The average seabed depth within the site boundary is approximately 100 m with a maximum of 150 m and a minimum of 70 m at the peaks of the rocky reef outcrops. The deepest depths are within the scour pits which encircle the outcropping rocky reefs.

The three reefs rise 15–35 m above the surrounding seabed and are composed of tertiary igneous rock and boulders, with the reef tops composed of silty bedrock, with a patchy veneer of muddy sediment due to sediment deposition from a localised scouring process. The reefs support a diverse animal community, including hydroids (e.g. Diphasia nigra), a range of sponges, including the cup sponge Axinella infundibuliformis, echinoderms, for example the cushion star fish Porania pulvillus and various crustaceans, for example the edible crab Cancer pagurus and squat lobster Munida rugosa. Additionally, the reef may provide shelter for juvenile fish, including blue whiting, bib, red gurnard and wrasse. In particular, the mosaic of bedrock and stony reef provide a myriad of ledges and habitat niches. Of note is the occurrence of the Diphasia alata hydroid community which is not currently included within the Marine Habitat Classification for Britain and Ireland and is considered rare. The difference in species composition and abundance between the reefs and the surrounding mud plain highlights the importance of the reefs in providing a refuge for numerous species.

Site location:  Co-ordinates for this SAC can be found in the Standard Data Form listed in the Relevant Documentation section.

Site area:  This site protects three key features covering a total area of 8.73 km2. These three areas combined are approximately the same size as nearby Larne Lough.

Site depth range: The site sits in a mud basin, with the reef features protruding, sitting at their shallowest between 70 m below sea-level, and the deepest parts in the scour pits around the rock features reaching down to 150 m below sea-level. 

Charting Progress 2 Biogeographic Region: Irish Sea.

Site boundary description: The site boundary for the Pisces Reef Complex SAC has been defined using JNCC’s marine SAC boundary definition guidelines. The boundary is made up of three separate polygons enclosing the minimum area necessary to ensure protection of the Annex I habitats. It does not include the areas of muddy sediment that lie between the reefs. The bedrock reef features were derived from collating survey data from various detailed acoustic and biological surveys. The areas of bedrock and stony reef that met the definition of Annex I reef were delineated based on the interpretation acoustic data, which showed a clear distinction between the hard and soft substrates. Seabed modelling using the Benthic Terrain Modeller (NOAA) was also carried out for all three areas. Refer to the Monitoring and Evidence section for further detail on the data for this MPA. As any bottom trawling that occurs in the area may pose a threat to the reef, the boundary includes a margin to allow for mobile gear on the seabed being at some distance from the location of a vessel at the sea surface. This buffer has been applied individually to each of the reef features of the site.


Monitoring and Evidence

Last updated: November 2023

The full overview of the various data used to support site identification, along with information on confidence in feature presence and extent is available in the Pisces Reef Complex SAC Selection Assessment Document. JNCC will be adding relevant survey data for this MPA to its MPA Mapper in due course.

Some of the data for this SAC have been collected through JNCC-funded or collaborative surveys and some through other means. Data from these surveys/this survey provide direct evidence confirming the presence of the protected features within the site.


Survey and data gathering

  • Pisces Reef MPA Monitoring Report 2016 (2022) – This report explores environmental and ecological sample data, primarily acquired from a survey of Pisces Reef Complex MPA in 2016, which are intended to serve as first point in a monitoring time series. It also includes recommendations to inform continual improvement and development of sample acquisition, analysis and data interpretation for future survey and reporting.
  • Monitoring survey of Pisces Reef Complex SAC (2017) – The monitoring survey at Pisces Reef Complex SAC was carried out in autumn 2015. A variety of data types were collected during the six-day survey including multibeam echosounder bathymetry and backscatter, chirper sub-bottom profiles, high-resolution video and stills, and water samples to calibrate the camera frame mounted CTD. The survey aimed to: (1) Acquire sentinel monitoring data to support the ongoing monitoring time-series for the Pisces Reef Complex; and (2) Provide evidence on the structure, function and condition of the Annex I Reefs (both rocky and stony) against which the direction of change can be inferred over time.
  • Pisces Reef Complex SAC and Slieve Na Griddle rMCZ Drop Camera Survey (CEND1414) (2014) – JNCC were offered the opportunity to use part of a planned survey in order to collect further targeted data within Pisces Reef Complex SAC and Slieve Na Griddle rMCZ. AFBI collected camera tow and still image data to further verify the extent of the Annex I Reef feature within the two southernmost extents of the SAC. Reporting is underway and will be made available in due course.
  • Slieve Na Griddle rMCZ Site Verification Survey (2012) – JNCC commissioned the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) to undertake an MCZ Site Verification survey on the recommended MCZ Slieve Na Griddle, the boundary of which overlaps two of the three reef features comprising Pisces Reef Complex SAC. High-resolution multibeam, video and grabs were collected, presenting comprehensive acoustic and further ground-truthing data for the two features named Pisces Reef 1 and 2. Reporting is underway and will be made available in due course.
  • Beaufort’s Dyke – North Channel Biophysical Survey (2008) – The British Geological Survey (BGS) were invited to participate in a survey of Beaufort's Dyke, North Channel in the Irish Sea by AFBI, aboard the RV Corystes in order to carry out seismic data collection over the Pisces Reef Complex. The purpose was to gather data which could be used to provide seismic profiling of features identified on the multibeam echosounder, supporting the findings of rocky reef protruding from the seabed. Subsurface data were gathered by sub-bottom profiler (sparker), and the data are archived by BGS.
  • Marine Institute Seabed Mapping (2006) – The Irish Marine Institute collected acoustic and ground-truthing data in the area of Pisces Reef aboard the RV Celtic Voyager in 2006, including multibeam and sub-bottom profiler acoustic data, alongside a single grab at each location for particle size analysis.
  • AFBI MESH Seabed Mapping (2005) – The Agri-Food and Biosciences Institute of Northern Ireland (AFBI) tested habitat mapping protocols across several seabed features, including Pisces Reef. Sidescan, video tow, grab and sediment sample data were collected aboard the RV Corsytes.
  • MESH NW Shelf Consortium (2005/2006) – Tested habitat mapping protocols and ground-truth assessment methodology on selected seabed features. MESH North Western Shelf Consortium (formed by Marine Institute, British Geological Survey, Department of Agriculture & Rural Development (DARD) (now Agri-Food Biosciences Institute: AFBI), Queen's University of Belfast and the University of Ulster) undertook survey work to test mapping protocols which included the Pisces Reef region: AFBI and Marine Institute Mapping.
  • Geophysical Survey of the Irish Sea (2004) – As part of the SEA6 project geophysical survey, work investigated possible occurrences of methane-derived authigenic carbonate (MDAC), which form hard substrate on the seabed. A range of acoustic techniques were used including: single-beam echosounder (SBES), multi-beam echosounder (MBES), side-scan sonar (SSS), and chirp sub-bottom profiler (SBP) in August 2004 (SV Meridian). Ground-truthing data included photography, seabed sediment sampling (grab samples), and water sampling in October 2004 (SV Kommandor Jack). MDAC was not located at the Pisces Reef, but showed a substantial rocky outcrop lying within an area of soft muddy sediments. Analysis of the video and still imagery confirmed the presence of bedrock/stony reef and identified the major faunal communities.
  • Strategic Environmental Assessment (SEA 6) of the Irish Sea (2004) – The Department of Energy & Climate Change (DECC) (then the Department of Trade and Industry (DTI)) carried out a Strategic Environmental Assessment in the Irish Sea region in 2004 in order to better understand the implications of oil and gas exploration and production. 
  • Irish Sea Seabed Image Archive (ISSIA) A directory of Seabed Camera Studies in the Irish Sea – compilation of images taken in the Irish Sea 1999. Report 2.  This report has not been digitised and is only available in hard copy.
  • Geological investigations with a manned submersible in the Irish Sea and off western Scotland (1971) – IGS (now British Geological Survey (BGS)) deployed a manned submersible to  establish the presence of hard substrate around ‘Pisces Reef 2’, the central outcropping of the three features. This report is only available in hard copy.


Data analysis report


Additional relevant literature

References for further supporting scientific literature consulted during the identification of this site can be found in the SAC Selection Assessment Document. Please be aware that although these sources contain information in relation to this MPA, they do not necessarily represent the views of JNCC.


Knowledge gaps

As part of the UK Marine Monitoring and Assessment Strategy (UKMMAS), JNCC led the development of a UK Marine Biodiversity Monitoring Strategy, working with partners across the UK monitoring community. The Strategy spans UK territorial and offshore waters, focusing on biodiversity in the wider environment and within Marine Protected Areas.  Its aim is to implement efficient, integrated monitoring of marine biodiversity to provide the evidence needed for all the UK's policy drivers.

The evidence collected during MPA monitoring surveys is used in combination with other available evidence to:

  • Enable assessment of condition of the features within sites;
  • Contribute to the assessment of the degree to which management measures are effective in achieving the conservation objectives for the protected features;
  • Support the identification of priorities for future protection and/or management; and,
  • Enable Government to fulfil its national and international assessment and reporting commitments in relation to MPAs and help identify where further action may be required.

More detail on offshore MPA monitoring can be found on the Offshore MPA monitoring webpage. A list of monitoring surveys and relevant reports can be found  on the MPA monitoring survey reports webpage.

If you are aware of any additional information not referred to in any of the Relevant Documentation section, please contact us.


Conservation Advice

Last updated: March 2018

Updated formal conservation advice is now available for this MPA. Further information on the approach used to develop this advice is available on our 'Conserving MPAs' webpage along with a Glossary of Terms used in JNCC conservation advice and a short video explaining how to use the conservation advice packages. 

You must refer to this advice if you:

  • undertake a Habitats Regulation Assessment (HRA) for a plan or project that could impact the site;
  • provide information for a 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.

You may also find it useful to refer to this advice if you:

  • carry out any other activity that could impact the site.

We will engage with stakeholders to identify any lessons which JNCC can learn from customers who have used the advice, with a view to continuing to ensure it is fit-for-purpose.

The following table provides an overview of the components of the conservation advice, and provides hyperlinks to each of the products for this MPA. These elements together form JNCC’s formal conservation advice for this site and should be read in conjunction with each other.  This advice reflects the most up-to-date evidence held by JNCC (correct as of March 2018). 

Document Overview
Background Information Explains the purpose of the advice and when it must be referred to.

Conservation Objectives


Supplementary Advice on the Conservation Objectives (SACO)

The Conservation Objectives set out the broad ecological aims for the site. JNCC provides supplementary advice in the SACO which is essential reading to support interpretation of these conservation objectives.

You can use these documents to assess the impacts of your planned activity on the important attributes of the site.

Conservation Advice Statements

These statements provide a summary of the Supplementary Advice on the Conservation Objectives (SACO).

  • Site condition presents our up-to-date understanding of the condition of features within the site;
  • Conservation benefits which the site can provide, these help you understand what is important about the site and why it needs protecting; and
  • Conservation measures which JNCC considers are needed to support achievement of the conservation objectives. These provide clarity around measures needed to support restoration or maintenance of the feature(s) within the site.
Advice on Operations

Provides information on the activities capable of affecting site integrity and therefore achievement of the site’s conservation objectives.

This is a starting point for determining potential management requirements. It does not take into account the intensity, frequency or cumulative impacts from activities taking place. It is simply to advise you of the possible adverse impacts that your activity can have on a MPA’s features.

Use the advice on operations to determine those pressures your activity causes that could harm the habitat and/or species features of the site.

These resources are available on JNCC's Resource Hub.


Activities and Management

Last updated: June 2017

Management status: Progressing towards being well managed.

Progress is ongoing with the recommendation of fisheries management proposals. A monitoring survey was undertaken in 2016 to improve our understanding as to whether the MPA is moving towards or has reached its conservation objectives. Ongoing site condition monitoring work will be required however in order to conclude with confidence as to the degree to which the site is moving towards or achieving its conservation objectives.

This site forms part of the networks of MPAs across the UK and contributes to international MPA 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 Pisces Reef SAC around each of the four stages in the MPA management cycle.


1. The documentation of appropriate management information

  • The conservation objectives and advice on activities capable of affecting the conservation status of the protected feature of this site are available under the Conservation Advice section. Further information is available on our 'Conserving MPAs' webpage.
  • Spatial information on the presence and extent of the protected feature of this MPA is available via JNCC's MPA Mapper.
  • JNCC is in the process of developing downloadable MPA data packages where appropriate permissions to share datasets are in place.


2. 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. The protected feature of the site is considered to be sensitive to pressures associated with fishing and ‘licensable’ activities.


  • There is evidence of mobile demersal and pelagic activity within the MPA.
  • The Marine Management Organisation is the lead authority regarding the implementation of, and compliance with, any measures to managing fishing activity. Further information on progress is available on the Marine Management Organisation’s webpages.

Licensable activities

  • Whilst 'licensable' activities such as oil and gas exploration and production do not take place within Pisces Reef Complex SAC at present, any future proposals would have to comply with Regulation 28 (Protection of European offshore marine sites and European sites) of The Conservation of Offshore Marine Habitats and Species Regulations 2017 (as amended).
  • Our conservation advice supports the consents process by setting out the conservation objectives for the protected feature of this MPA and advice on activities that may result in pressures to which the protected feature is considered sensitive.
  • 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


3. Site condition monitoring

A baseline condition monitoring survey for this MPA was undertaken in 2016. The survey aimed to gather evidence to monitor and inform assessment of condition of the Annex I Reefs within the site. The results of this survey are not yet available. Further information will be made available in the Monitoring and Evidence section in due course.


4. Assessment of progress towards conservation objectives

No long-term condition monitoring data is available to determine whether the MPA is moving towards or has reached its conservation objectives. The site has a ‘maintain’ conservation objective based on the findings of a vulnerability assessment (exposure the activities associated with pressures to which the protected features of the site are considered sensitive). This suggests the site may already be achieving or moving towards its conservation objectives. Site condition monitoring data would improve our confidence in this assessment.



Published: .

This Site Information Centre (SIC) was created 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 created. These references will be revised as necessary when the SIC is next substantially revised. Requirements through EU legislation are retained in the UK so existing environmental protections and standards remain, and the protection given to habitats and species continues.

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