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Central Fladen MPA

Status: Nature Conservation Marine Protected Area (Nature Conservation MPA)

The Central Fladen MPA lies within the Fladen Grounds, a large area of mud in the northern North Sea. The mud habitat is characterised by feather-like soft corals called sea-pens, and burrows made by crustaceans such as mud shrimp and the Norway lobster.




The Central Fladen MPA lies in a large area of mud in the northern North Sea – the Fladen Grounds. The churning of the mud by burrowing animals releases nutrients and helps mix oxygen into the mud, supporting a wide diversity of life. The southern area of the MPA includes examples of the nationally scarce tall sea-pen, which can grow up to 2 m in height. The MPA has also been shaped to include a tunnel valley on the seafloor representative of an area of geomorphological interest known as the 'Fladen Deeps'. It is thought these valleys were created by erosion of meltwater under an ice sheet in former ice ages.

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

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

Map showing Central Fladen Marine Protected Area and linking to the MPA mapper


Legislation behind the designation: Marine and Coastal Access Act (2009)


Protected Features

Feature Feature Type
Burrowed mud (sea-pens and burrowing megafauna and tall sea-pen components) Habitat
Sub-glacial tunnel valley representative of the Fladen Deeps Key Geodiversity Area Geomorphological feature

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 the Central Fladen Nature Conservation MPA. More detail can be found within the Relevant Documentation section.

November 2012
Site recommended to Marine Directorate.
Summer 2013
Site subject to formal public consultation and becomes material consideration in licensing processes.
July 2014
Site designated by Marine Directorate as a Nature Conservation MPA.


Relevant Documentation

The documents referred to below and any other historical documents relating to the Central Fladen Nature Conservation MPA 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 Nature Conservation MPA site selection process is available on JNCC's Nature Conservation MPA webpages.

The Relevant Documentation is available on JNCC's Resource Hub.



Last updated: October 2017

Information for this site summary was adapted from the Central Fladen Site Summary Document and incorporates any further information gathered since this document was produced. Please refer to this document in the Relevant Documentation section for further details and information sources.


Site overview

The Central Fladen MPA lies within the Fladen Grounds, a large area of mud in the northern North Sea named after the German word "fladen" meaning "flat cake". The MPA includes a particular type of mud habitat that is characterised by feather-like soft corals called sea-pens, and the burrows made by crustaceans such as mud shrimp and the Norway lobster (Nephrops norvegicus, also known as the Dublin Bay prawn or langoustine). Burrowed mud is an interesting and important marine habitat that supports a rich community of animals. Burrowing species can be found living within the mud itself. Their burrowing activity plays an important role in supporting life in the area; the constant churning of the mud releases nutrients and helps to mix oxygen into the mud. Longer-lasting burrows also provide shelter to other marine life from the starfish and sea urchins that patrol the muddy surface looking for food. Burrowed mud is considered by OSPAR to be a Threatened and/or Declining habitat across the North-east Atlantic.

Several different types of sea-pen can be found anchored in the muddy seabed within the MPA. The southern area includes examples of the nationally uncommon tall sea-pen (Funiculina quadrangularis), which can grow up to 2 m in height. Brittlestars use the tall sea-pen as an elevated perch to filter food from passing currents.

The MPA has also been shaped to include an unusual tunnel valley, representing part of a Key Geodiversity Area known as the Fladen Deeps or 'The Holes'. It is thought these valleys were created by erosion of meltwater under an ice sheet in former ice ages. In places, these tunnel-valleys can stretch for 40 km and be 4 km wide. The Fladen Deeps are considered scientifically important since they hold potentially valuable evidence about past changes in the extent and geometry of the last British-Irish Ice Sheet. Further detail on the evidence for this Nature Conservation MPA can be found in the Monitoring and Evidence section.

Site location:  Co-ordinates for this Nature Conservation MPA can be found in the Designation Order listed in the Relevant Documentation section.

Site area: 925 km2.

Site depth range:  The minimum depth within this Nature Conservation MPA is 100 m below sea-level, whereas the 'Fladen Deeps' sub-glacial tunnel-valley that runs through the MPA is the deepest area of the site and reaches depths of 280 m below sea-level.

Charting Progress 2 Biogeographic Region: Northern North Sea.

Site boundary description: The MPA boundary was drawn to include survey records of burrowed mud habitat, mostly including areas where the distribution of the sea-pen species meet or exceed the average density of sea-pens from across the wider Fladen Grounds based on available survey data. The southern part of the MPA boundary was drawn to include one of the only areas where tall sea-pen have been recorded in Scottish offshore waters. The MPA also includes the entirety of a sub-glacial tunnel-valley geomorphological feature representative of the Fladen Deeps Key Geodiversity Area.


Monitoring and Evidence

Last updated: April 2024

There are a range of data that underpin this Nature Conservation MPA. The full overview of the data used to support site identification along with information on confidence in feature presence and extent is available in the Central Fladen Nature Conservation MPA Data Confidence Assessment. JNCC will be adding relevant survey data for this MPA to the its MPA mapper in due course.

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


Survey and data gathering

  • MRV Scotia (2023) – This JNCC and Marine Directorate 0723S survey collected data about the condition of animals and habitats within the MPA, helping us to monitor change within the site. More information is available in the survey blog.
  • RV Cefas Endeavour survey (2014) – This JNCC-led survey collected data about the ecological communities across the Fladen Grounds, and also sought to improve our understanding of feature condition in the Nature Conservation MPA.
  • RV Cefas Endeavour survey (2013) – This JNCC-led survey of the Fladen Grounds set out to map the presence of burrowed mud habitat, including the sea-pens and burrowing megafauna communities in circalittoral fine mud across the region. 
  • International Bottom Trawl Survey Quarter 3 (2011) – JNCC collaborated with Marine Scotland Science on this survey to undertake habitat survey work to verify the presence of sea-pens and burrowing megafauna communities in circalittoral fine mud.


Data analysis reports

  • JNCC/MSS Partnership Report (2021) – This report describes the Central Fladen MPA Video Analysis on Imagery Analysis, Density Assessments and Results
  • Analysis of CEND01/13 Fladen Grounds survey (2017) – This report presents findings from the analyses of samples collected during the CEND01/13 Fladen Grounds pMPA survey. The main aim of this survey was to confirm the presence of Priority Marine Features (burrowed mud) within the pMPAs and provide evidence to allow comparison of benthic assemblages between the sites. 
  • Monitoring options report (2016) – This report describes monitoring options for the Central Fladen Nature Conservation MPA, and offshore mud habitats more generally, based on survey data collected in 2014.
  • EMODnet – Provides supporting information on the presence and extent of sedimentary features from a predictive seabed habitat map of European waters.
  • Report on the identification of Key Geodiversity Areas in Scotland’s seas (2013) – This report helped support information on the presence and extent of important geological/geomorphological areas in Scotland’s seas, which includes the Fladen Deeps Key Geodiversity Area of relevance to this Nature Conservation MPA. 
  • Marine Scotland Science Nephrops Towed Video Analysis – Marine Scotland Science processed video data from their Nephrops stock assessment work to report on the presence of sea-pens and burrowing megafauna communities in the area.
  • Analysis from IBTSQ3 survey (2011) – Seabed imagery analysis from video/stills samples taken at two stations during 2011 confirm the presence of the burrowed mud feature.


Additional relevant literature

References for further supporting scientific literature consulted during the identification of this site can be found in the Central Fladen Data Confidence Assessment document.


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 Marine Directorate of Scottish Government, in partnership with JNCC and NatureScot, developed a Scottish Marine Protected Area (MPA) monitoring strategy. The Strategy spans Scottish territorial and offshore waters, focusing on biodiversity within Marine Protected Areas. The Strategy is supported by a series of annexes which provide more detail on monitoring methods, collaborative working, current monitoring and a two year forward look for MPA monitoring in Scottish waters.

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 data or relevant scientific papers for this site not listed here or in the Relevant Documentation section please contact us.


Conservation Advice

Last updated: March 2018

Updated formal conservation advice for this MPA was produced in March 2018. Further information on the approach used to develop this advice is available on our Conservation Advice webpages, along with a Glossary of Terms used in JNCC's conservation advice, and a short video explaining how to use the conservation advice packages. 

You must refer to this advice if you:

  • undertake an impact assessment for a plan or project that could impact the site;
  • provide information for such an assessment;
  • respond to specific measures to further 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.

Please note our current understanding of whether the available evidence indicates that each attribute needs to be restored or maintained is not provided here. However, links to available evidence for the site are provided and should you require further site-specific information for the site, please contact us.

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.

Feature Activity Sensitivity Tool (FeAST)

Provides an initial assessment of whether a proposed plan or project (or ongoing activity) may have an impact on a protected feature in the site.

FeAST identifies pressures associated with the most commonly occurring marine activities, and provides a detailed assessment of feature sensitivity to these pressures. A human activity is considered capable of affecting, other than insignificantly, a feature where the feature is known to be sensitive to associated pressures.

The sensitivity assessments provided in FeAST, should be used at an early stage of a plan or project when considering potential impacts of an activity.

These Conservation Advice documents are available on JNCC's Resource Hub.



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