Outer Thames Estuary SPA


Status: Special Protection Area (SPA)


The Outer Thames Estuary SPA is classified for the protection of the largest aggregation of wintering red-throated diver (Gavia stellata) in the UK, an estimated population of 6,466 individuals, which is 38% of the wintering population of Great Britain .


This SPA crosses the 12 nautical mile boundary and therefore lies partly in territorial and partly in offshore waters; hence it is a site for which both Natural England and JNCC have responsibility to provide statutory advice. The SPA lies along the east coast of England in the southern North Sea and extends northward from the Thames Estuary to the sea area off Great Yarmouth on the East Norfolk Coast.

Formal consultation on proposed extensions to the existing Outer Thames Estuary SPA boundary closed on the 14 July 2016. The proposed extension would afford protection for little tern and common tern foraging areas, enhancing the protection already afforded to their feeding and nesting areas in the adjacent coastal SPAs (Foulness SPA, Breydon Water SPA and Minsmere to Walberswick SPA).


More detailed site information can be found on the Summary tab below.


Farnes East MCZ Boundary



Map displaying the MPA boundary

View and download spatial data for this MPA

on the JNCC UK MPA interactive map.

























Legislation behind the designation: EU Birds Directive 2009/147/EC, as transposed into UK law by the Conservation of Habitats and Species Regulations 2010 (as amended) within 12 nautical miles, and the Offshore Marine Conservation (Natural Habitats, & c.) Regulations 2007 (as amended) between 12 nautical miles out to 200nm or the Continental Shelf. 


Protected Features:

Features Feature Type % of population  Conservation objective
Red-throated diver Gavia stellata                Annex I species             38% GB

Maintain or Enhance



Conservation Objectives
The overarching conservation objectives for the designated features of all protected sites in UK offshore waters is to ensure they either remain in, or reach favourable condition. The ability of a designated feature to remain in, or reach favourable condition can be affected by its sensitivity to pressures associated with activities taking place within or in close proximity to a protected site.


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

Site Timeline

The diagram below is a summary of the key milestones involved in the selection and classification of the Outer Thames Estuary SPA. 

Relevant documentation

The documents referred to below and any other historical documents relating to The Outer Thames Estuary 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.

  • Natura Standard Data Form - provides details about the SPA and the classified feature.  
  • Departmental Brief - a more detailed overview of the SPA, and rationale for the classification of the site.
  • Conservation Objectives and Advice on Operations - information about feature sensitivity, vulnerability and risk, and the Conservation Objectives for the classified feature of the site. 
  • Site Improvement Plan - provides a high level overview of the current and predicted issues affecting the condition of the site's protected feature and outlines the priority measures required to improve the condition of the feature. It does not cover issues where remedial actions are already in place or ongoing management activities which are required for maintenance.

Information about the SPA site selection process is available on the JNCC SPA pages.



Site overview

The Outer Thames Estuary SPA lies along the east coast of England, predominantly in the coastal waters of the southern North Sea between the Thames Estuary and the east Norfolk coast. It covers an area of c. 3,800km2, classified for the protection of wintering red-throated diver. This area supports the largest aggregations of wintering red-throated diver in the UK, 38% of the GB population.

The area of the SPA contains areas of shallow and deeper water, with high tidal current streams and a range of mobile sediments, including several shallow sandbanks. Much of the area is less than 20m water depth, extending into the 20-50 m depth contour towards the eastern boundary of the SPA.

The population estimate for wintering red-throated diver in the Outer Thames Estuary SPA was based on data collected from visual aerial surveys within the period from January 1989 to the winter seasons of 2005/06 and 2006/07. These data demonstrate that the Outer Thames Estuary SPA regularly supports numbers of red-throated diver that are well in excess of the percentage population threshold (>1% of the GB population of this species) identified under the UK SPA selection guidelines (Stroud et al. 2001).  


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

Site location:  the boundary of this SPA can be viewed or downloaded via the JNCC MPA mapper. Boundary co-ordinates for the site are available from this site boundary map.

Site area:  c. 3,800km2


Site depth range:  Water depth within the site ranges from mean low water to 20-50m depth along the seaward boundary of the site.


Site boundary description
The SPA boundary is divided into three areas: the outer part of the Thames estuary; a separate area extending south along the coast from East Norfolk; and a third area lying seaward of this off Lowestoft. The landward boundary follows the Mean Low Water mark or the seaward boundaries of existing SPAs, whichever is furthest seaward, except where there was evidence of low densities of red-throated diver. The boundary of this SPA extends into offshore waters beyond 12 nautical miles; hence it is a site for which both Natural England and JNCC have responsibility to provide statutory advice.

Information for this site summary was adapted from documents listed in the relevant documentation section. 


Site specific data

The full overview of the data used to support site identification along with information on confidence in the protected features occurrence and abundance is available in the Outer Thames Estuary SPA Departmental Brief

Data for this SPA has been collected by the Nature Conservancy Council (NCC), the Joint Nature Conservation Committee (JNCC), the Wildfowl & Wetlands Trust (WWT) and the Natural Environmental Research Institute, Denmark (NERI). Surveys carried out by WWT and NERI were commissioned in response to proposals to develop wind farms in the Greater Thames and in other areas around the UK. The surveys were commissioned by a consortium of private companies, as well as DBERR (Department for Business Enterprise and Regulatory Reform, formerly Department of Trade and Industry (DTI), the Department for the Environment, Food and Rural Affairs (DEFRA) and the Crown Estates. Data from these surveys provide direct evidence for the numbers of red-throated diver within the site.


Survey and data gathering

  • Visual aerial survey 1988/89 – 2006/07. A series of three strip transect aerial surveys were undertaken in the winter seasons 1988/89 and 1989/90, and 20 line transect aerial surveys were conducted between the winter seasons 2001/02-2006/07. Further details on the methods and survey coverage are available in JNCC report 374 below.
  • UK inshore areas for wintering seaduck, divers and grebes (JNCC report 333, 2003). This report describes the methods used during aerial surveys of seaduck, divers and grebes during the winters of 2000/01 and 2001/02, and presents the numbers and distributions of those species recorded in each area of the SPA. These surveys (of the Outer Thames Estuary) were used in the evidence base and analysis for the Outer Thames Estuary SPA.


Data analysis reports


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:

  • Skov, H., Heinänen, S., Thaxter, C.B., Williams, A.E., Lohier, S., Banks, A., N. 2016. Real-time species distribution models for conservation and management of natural resources in marine environments. Marine Ecology Progress Series 542, 221-234.
  • Goodship, N., Caldow, R., Clough, S., Korda, R., McGovern, S., Rowlands, N., & Rehfisch, M. 2015. Surveys of Red-throated Divers in the Outer Thames Estuary. British Birds 108, 506-513.
  • O’Brien, S.H., Webb, A., Brewer, M.J., Reid, J.A. 2012. Use of kernel density estimation and maximum curvature to set Marine Protected Area boundaries: Identifying a Special Protection Area for wintering red-throated divers in the UK. Biological Conservation 156, 15-21.
  • O'Brien, S.H., Wilson, L.J., Webb, A. & Cranswick, P.A. 2008. Revised estimate of numbers of wintering Red-throated Divers Gavia stellata in Great Britain. Bird Study 55:2, 152-160.


Knowledge gaps
If you are aware of any additional data or relevant scientific papers for this site not listed in the relevant documentation , please contact JNCC.



Conservation Advice

Conservation objectives

Conservation objectives set out the desired state for the protected features of an MPA. The conservation objectives for the protected features of the Outer Thames Estuary SPA have been set based on knowledge of the condition of the protected features at the time of writing. JNCC and Natural England have published joint advice for this site within the Conservation Objectives and Advice on Operations document.


The 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 Conservation Objectives for the protected features of the SPA are:

The conservation objectives for the Outer Thames Estuary Special Protection Area is, subject to natural change, maintain or enhance the red-throated diver population (Gavia stellata) and its supporting habitats in favourable condition.

The interest feature red-throated diver will be considered to be in favourable condition only when both of the following two conditions are met:

  • The size of the red-throated diver population is at, or shows only non-significant fluctuation around the mean population at the time of designation of the SPA to account for natural change; and
  • The extent of the supporting habitat within the site is maintained.


More information on the conservation objectives for this SPA is provided in the Outer Thames Estuary SPA Conservation Objectives and Advice on Operations document.

JNCC is working to provide more detailed advice on the relatively broad, high level conservation objectives listed above. This supplementary advice will be posted here as and when it becomes available.


Advice on operations 

In line with Regulation (18) of the Offshore Marine Conservation (Natural Habitats, & c.) Regulations 2007 (as amended) which apply to the UK’s offshore marine area and Regulation 35(3) of the Conservation of Habitats and Species Regulations 2010 (as amended), which apply to England’s and Wales inshore waters, the advice on operations for the protected features of the Outer Thames Estuary SPA outline knowledge of the nature and extent of activities taking place at the time of writing which may have a significant impact on the features for which a site has been selected.

The advice on operations is based on JNCC and Natural England’s scientific knowledge of the feature at the time of writing and their sensitivities to pressures. For the most up-to-date information about the feature within the site and the spatial distribution, please see the evidence tab.

JNCC also provides a list of activities occurring within the site and information on activity management in the activities and management tab. This information is also useful when assessing an activity, plan or project which may affect the protected features and JNCC has provided this to aid the cumulative assessment of impacts of human activities within the site. While every attempt has been made to ensure this information is accurate and kept up-to-date, the list is not to be considered exhaustive or definitive. The list does not, for example, include activities occurring off-site which may also be capable of affecting the protected features.

The information contained within the advice on operations, activities and management tab, evidence tab, are useful if you are:

  • Carrying out any activity that may impact the site and need to find out how to operate within the law
  • an authority providing advice on specific proposals
  • an authority responsible for putting management measures in place 


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 and Natural England’s conservation advice will be kept under review and will be periodically updated to reflect this and surveillance required under Article 12 of the Birds Directive. Conservation advice for sites which straddle the 12nm boundary will continue to be developed jointly with the relevant country nature conservation body. Further information on JNCC’s conservation advice work is available here. Information can also be found on Natural England’s website.




Activities known to be currently occurring within this SPA
(Activities information correct as of February 2016)

Licensed activities:

Aggregate extraction

  • Commercial aggregate extraction occurs mostly in the northern extent of the SPA offshore from Great Yarmouth, with some further licence areas off Felixstowe in the north part of the southern section of the SPA.


  • There are a number of operational offshore windfarm developments located within the Outer Thames Estuary SPA (Kentish Flats, Gunfleet Sands, Scroby Sands, London Array 1). A further two operational windfarms, and a consented development occur offshore to the east of the SPA boundary, and a leased area of overlaps the north eastern boundary of the SPA.

Existing licensed activities that take place or may take place in the future within the Outer Thames Estuary SPA will continue to be managed in line with relevant legislation and application processes by the competent authorities. Information on JNCC's role in the provision of advice for licensed activities in the UK offshore area is available on the offshore industries advice webpages.



Evidence suggests that most of the fishing activity from vessels >15m is from beam and otter trawlers. Fishing by UK registered vessels using these bottom towed gears was concentrated in the middle portion of the site. While bottom-towed activity from non UK registered vessels was to the east of the site straddling the 12 nm limit and in a separate area in the south of the SPA. Fishing using lines, nets and pots also occurs across the site. There were few discernible patterns, with activity taking place throughout most of the year.

Fisheries management 

The Outer Thames Estuary SPA extends from the coastline beyond the 12nm limit. Within 6nm of the coast, only UK vessels operate and any management in this area would be implemented by Inshore Fisheries and Conservation Authorities (IFCAs) or the MMO. Between 6 and 12nm, French and Belgian fishing vessels have access to the site, to implement any fishing restrictions in this area Defra would negotiate with the relevant governments before introducing national fishing prohibition orders applicable to all EU vessels or introducing CFP regulation measures. The section of the SPA lying offshore (beyond 12nm) is also fished by other member states including the Netherlands, Denmark, and Germany. Fisheries are managed through the Common Fisheries Policy (CFP) in all areas beyond 12nm. However there is no site-specific fisheries management currently in place to protect the designated features of this site. Defra and the Marine Management Organisation (MMO) are leading discussions with stakeholders regarding the development of management for sites on a regional basis. JNCC will provide advice on possible management options to support these discussions. Following engagement with stakeholders, management proposals will be drawn up.

In accordance with Article 18 of the revised CFP, the UK government will seek to develop management proposals jointly with any Other Member States with a direct management interest in the area. Once drafted, there is a requirement to consult the relevant Advisory Council (North Sea AC) prior to submission of any final request to the European Commission. The UK Marine Management Organisation will be the lead UK authority regarding enforcement and compliance of any measures.
The Marine Management Organisation (MMO) published a draft site assessment for the Outer Thames Estuary SPA, this document includes draft recommendations on how fisheries should be managed in this SPA. Consultation on this draft site assessment document closed on the 15 February2016. For further information on the MMO’s MPA Assessment and how fisheries are managed within MPAs generally, please see their website.

 Other activities:

  • Cables and pipelines - One power cable crosses the southern part of the SPA. In the northern half of the SPA nine telecommunications cables and one gas pipeline cross through the site.
  • Shipping and ports – The SPA is situated in a busy marine area; subject to large scale permanent infrastructure, busy shipping lanes, and other vessel movement. Impacts from shipping could cause a displacement of red-throated divers, though shipping activity has been undertaken in the Thames Estuary for many hundreds of years. The impacts from historical shipping on the red-throated diver population are unknown, shipping activities are largely confined to existing shipping lanes, which are already known to be avoided by Divers. 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). 
  • Port of London is one of the UK’s largest ports and the Port of London Authority (PLA) has responsibility for ensuring safe navigation. Maintenance dredging of existing channels extends out into the deep water approach channels in the outer estuary. The proposed approach channel to the consented London Gateway Port (Dubai Ports World) will pass through the site. Felixstowe, the UK’s largest container port, the Port of Ipswich and the Port of Lowestoft also occur within the bounds of this SPA, along with the associated shipping traffic and channel maintenance activities. A new port facility at Great Yarmouth is currently under construction and is expected to accommodate container traffic.
  • Coastal industry - There are no industries along the coastline bordering this SPA with significant discharges directly into the sea. However, direct discharge into the sea comes from treated sewage outfalls, and a thermal plume is discharged from Sizewell B nuclear power station.
  • Recreational use - The coastal areas of the Thames Estuary and the Suffolk and Norfolk coasts attracts a wide variety of marine recreational activities including sailing, boat trips, bird watching, sea angling, water sports and scuba diving. The majority of this activity is restricted to the inshore waters of the estuaries and coast.
  • Ministry of Defence - The Outer Thames Estuary SPA overlaps with areas identified for MoD activity, including firing practice areas along the south coast of Essex. A historic explosive dumping ground also occurs within the SPA. The MoD seeks to manage its activities in a manner that minimises environmental impact, as described within the Maritime Environment Sustainability Appraisal Tool.


Site management

Natural England, who are jointly responsible for this site, have produced a Site Improvement Plan for the inshore aspect of this site. The plan provides a high level overview of the issues (both current and predicted) affecting the condition of the sites protected features and outlines the priority measures required to improve their condition.




JNCC is currently leading on the development of options for biodiversity monitoring across all UK waters. JNCC’s advice for 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 


  • Digital aerial survey 2013. Two aerial surveys using high-resolution digital photography were undertaken by APEM in January, and February. These surveys provide the first population estimate for the SPA based on digital aerial survey techniques. Further details are available in the paper Goodship et al. 2015.





Every six years, Member States are required under Article 12 of the EU Wild Birds Directive (2009/147/EC) to report on their progress on the implementation of the Birds Directive. 

There is no site-level reporting required under Article 12; instead reporting consists of a national-level assessment that covers all regularly occurring wild bird species using an EU level agreed format.

Article 12 reporting consists of the following elements:

  • Population sizes
  • Population trends
  • Breeding distribution size and trend
  • Progress on implementation of action/management plans
  • Overview of the main pressures/threats (for some species only)
  • SPA population coverage and a summary of conservation measures taken
  • Information on Annex II species which are hunted under Article 7.


For seabirds, trend information from JNCC’s Seabird Monitoring Programme has been used – although where this information does not exist other national-level datasets have been used.  For some seabirds however, trend information remains unknown due to monitoring difficulties (e.g. for Manx Shearwater Puffinus puffinus).

The Article 12 report has a format that is closely aligned to Article 17 reporting under the EU Habitats Directive (92/43/EEC), with emphasis placed on the status and trends of bird species. This is providing a wealth of data and information to assess the efficacy not just of the Directive’s implementation, but also wider processes such as the EU’s 2020 Biodiversity Strategy as well as the Biodiversity Convention’s Aichi (2020) Targets.

The UK’s Article 12 report contributes to national data and the information has been used at international scales to produce the following outputs:

  • a first IUCN European Red List of birds;
  • a web-portal presenting submitted species data for each Member State;
  • a report from the European Commission to the European Parliament on the State of Nature in the EU;
  • a high level synthesis of the Article 12 and Habitats Directive Article 17 assessments;
  • an extensive technical summary of the Article 12 and Habitats Directive Article 17 data; and
  • a wide range of published academic studies using the data.



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