Marine ecology datasets for marine developments

If you need existing marine ecology data to apply for a proposed development or activity, we recommend you begin with this data.

The data is likely to be most useful at the scoping stage of any ecological assessment process that you need to carry out. It may help you to:

  • understand what ecological data is available for the geographical area relevant to your proposal
  • understand what marine habitats and species are present and the potential environment receptors and constraints to your proposed development or activity
  • plan any ecological surveys you need to undertake
  • design a monitoring programme for your proposed development or activity

How to check the relevance of the data

The relevance of this data will depend on the scale, nature and location of your proposed development or activity, as well as the pressures arising from it and the likely impact on ecological receptors.

All data have been collected over a range of timescales and as part of varied data acquisition programmes. Some of the data and datasets are from time-limited or one-off surveys or records, whilst others are components of ongoing surveillance and monitoring programmes.

The metadata and any supporting information associated with each of the datasets will help explain why and how the data was collected, when it was collected and what it covers. You should check this to help understand the relevance and usefulness of the identified datasets for your specific requirements.

Key external marine ecology datasets

The key external marine ecology datasets are:

Benthic data

Baseline data and seabed characterisation

This data is mostly point-source data from grabs, cores, dive surveys, drop-down and in-situ video and intertidal surveys. However, we also collect and use other forms of data, including acoustic mapping data such as side scan sonar and multibeam.

The point source data can include:

  • species records
  • species abundance
  • physical habitat data including particle size data for sediment samples
  • habitat descriptions
  • biotope records (derived from the species and physical habitat data for a sample point)

View point source seabed survey data within the Marine Recorder database. You can also view point source data on NBN Atlas Wales, but this may be at a coarser resolution. If sensitive data are required at a finer spatial resolution you will need to request it from the data holder.

Intertidal habitat survey map

View the GIS dataset for a complete intertidal habitat map for Wales (DataMapWales) Some data has been removed from the dataset in accordance with our operational guidance on ecological data which limits the spatial resolution at which some species data can be released. You can request the full intertidal habitat dataset from us.

Search our library catalogue for more reports relating to the intertidal survey.

Saltmarsh data

We collect saltmarsh monitoring data to:

  • asses feature condition within Special Areas of Conservation under the requirements of the Habitats Directive
  • as part of WFD assessments for selected transitional and coastal waterbodies

Search our library catalogue for saltmarsh reports.

Other useful datasets relating to saltmarsh include:

Water Framework Directive saltmarsh monitoring

Saltmarsh extent in this data may vary. This is could be due to:

  • the purpose for which the map has been produced
  • the methods used to collect the data and create the map
  • whether the mapping includes transitional vegetation such as inundation grasslands
  • the date when the dataset for the map was collected - saltmarsh is a dynamic habitat and extent and communities are expected to change over time

Search for records of saltmarsh species using the Online Atlas of British and Irish flora and the NBN Atlas Wales.

Habitats Directive Monitoring

We collect marine habitat and species monitoring data to assess marine site and feature condition. 

Find information on monitoring sites, habitats and species, side scan sonar survey locations and metadata for this work on the MEDIN portal.

Search the Marine Recorder database for more benthic monitoring data.

Water Framework Directive Monitoring

Marine ecological assessments form part of our Water Framework Directive (WFD) monitoring programme. See maps showing WFD status assessments for waterbodies in Wales on Water Watch Wales. They can also be accessed via the Welsh Government data portal DataMapWales.

The marine elements of our WFD monitoring programme are focused on transitional and coastal (TraC) waterbodies. Request individual datasets from any of our WFD TraC monitoring. Elements covered by our biological TraC monitoring in Wales include:

  • Benthic invertebrates
  • Macroalgae
  • Angiosperms
  • Angiosperms – saltmarsh
  • Fish
  • Phytoplankton

There is also WFD surveillance monitoring of imposex in dog whelk. Aerial photographs are available for the opportunistic algae, seagrass and saltmarsh monitoring.

We collect biological, physico-chemical, pollutants and hydro-morphology data in line with Monitoring under the Water Framework Directive guidelines. See detailed technical information about standards for WFD monitoring.

Habitats Directive SAC maps of Annex I marine habitat features

See maps of Special Areas of Conservation designated under the Habitats Directive (DataMapWales).

These provide the indicative baseline extent of features at the time of designation and are only updated where new data of sufficient confidence is available.

The indicative SAC feature maps are not the same as the maps used for Article 17 reporting (DataMapWales). You should use the SAC maps to assess the potential impact of your proposed development or activity on the habitat features of a SAC. To do this, please also refer to our conservation advice packages for Welsh marine SACs. The conservation advice packages also contain information on typical species associated with designated habitats.

Use the protected areas search to:

  • Find our advice for the cross border marine SACs (Dee Estuary SAC and Severn Estuary SAC)
  • Search for our core management plans and summary site maps for the other (not fully marine) SACs with Annex I saltmarsh features (Anglesey Coast: Saltmarsh SAC and Kenfig SAC)

Habitats Directive Article 17 reporting habitat feature maps

View and download DataMapWales' marine habitat feature maps relating to Article 17 of the EU Habitats Directive. These are a snapshot of the most up-to-date spatial data for features at the time of reporting, both inside and outside of SACs. They are reviewed and updated as part of a 6-yearly reporting cycle.

View JNCC's UK-level feature reports and maps.

Sites of Special Scientific Interest

Intertidal marine habitats and species in Wales may be protected as features of Sites of Special Scientific Interest (SSSI).

To find out more information on the features of individual SSSIs, use the protected areas search.

Skomer Marine Conservation Zone (MCZ)

We collect monitoring data for Skomer MCZ to provide the evidence needed to report on its condition. It also contributes to assessing the condition and conservation status of the Pembrokeshire Marine Special Area of Conservation, within which the MCZ is situated. See the latest project status report for the Skomer MCZ and other marine evidence and reports publications.

Habitats and species protected under other legislation

We collect and maintain data on marine habitats and species that are listed under Section 7 of the Environment (Wales) Act 2016 or that are designated as threatened and declining under the OSPAR Convention.

Using DataMapWales, view interactive map layers of some of the Section 7 and OSPAR habitats and species. Individual data layers within the habitat and species datasets indicate whether the habitat or species is included in Section 7 and/or on the OSPAR list of threatened or declining habitats or species. For some of the habitats there are both polygon and point data layers.

View EMODnet's OSPAR habitat and species maps for the whole of Europe.

Find individual species and habitat records for Wales on the NBN Atlas Wales.

Invasive non-native species

Search for records of non-native species found and reported in Welsh waters on the INNS portal. This supplements the GB Non-native Species Information Portal.

Additional data sources

View and download habitat maps collated by JNCC. The maps are standardised by translating into the EUNIS habitat classification system and formatting according to the European Marine Observation and Data Network (EMODnet) Seabed Habitats Translated Habitat Data Exchange Format.

UKSeaMap 2018 is a predictive full-coverage broad-scale seabed habitat map of seabed habitats in UK waters produced combining multiple models of physical parameters. EUSeaMap 2016 is the same but for European waters.

UK full-coverage EUNIS Level 3 Seabed Habitat Map is a GIS dataset providing full-coverage subtidal habitat information for the UK. It integrates data from field surveys and broad-scale predictive habitat model (UKSeaMap).

See Marine Protected Areas (MPAs) in Wales and the rest of the UK on JNCC. The names of individual sites can be identified by clicking within an MPA on the interactive map layer. Some designated site features can also be viewed by selecting the relevant layers.

Marine mammals

Cetaceans

Distribution maps - Wales

Modelled Distributions and Abundance of Cetaceans and Seabirds of Wales and Surrounding Waters (Evans and Waggitt 2023).

The report presents the distribution and abundance of cetacean and seabird species commonly occurring in Welsh waters and surrounding seas. It includes maps of sightings for 12 cetacean species and focuses on five species (harbour porpoise, bottlenose dolphin, common dolphin, Risso’s dolphin and minke whale) where enough data have enabled indicative density surface maps to be produced.

This report is an update to the 2012 Atlas of Marine Mammals of Wales (Baines and Evans 2012) which describes only relative sightings rates for the above species and the grey seal. The new report (Evans and Waggitt 2023) should be used in place of the 2012 Atlas.

The data outputs from this work are detailed in the data archive appendix of the report, and data can be downloaded from DataMapWales.

Harbour porpoise

In 2019, six SACs for harbour porpoise were designated in UK waters. The process involved comprehensive reviews of available data at the time. Those resources are available on each SAC page, for example here: West Wales Marine MPA | Advisor to Government on Nature Conservation | JNCC.

The bottlenose dolphin monitoring data (see below) also include incidental data on harbour porpoise sightings.

Bottlenose dolphin


SAC Condition Assessments

In 2025, SAC feature condition assessments were completed and involved a comprehensive review of available data. See reports for bottlenose dolphin and Pen Llyn a’r Sarnau and Cardigan Bay SACs here: Condition assessments for Welsh European marine sites (EMS).

Monitoring data

The following reports contain bottlenose dolphin monitoring data from Cardigan Bay. The 2020-24 report is currently in progress.

Bottlenose Dolphin Monitoring in Cardigan Bay 2014- 2016 Report 191. NRW Evidence report 191

Bottlenose Dolphin and Harbour Porpoise Monitoring in Cardigan Bay and Pen Llŷn a’r Sarnau Special Areas of Conservation 2011 - 2013 NRW Evidence Report No 4

The data outputs from this work are detailed in the data archive appendices of the reports. We can only release these data under licence and you should follow the procedures on the Accessing Our Data page of our website if you want to request the data.

Other key reports

  • Abundance and life history parameters of bottlenose dolphin in Cardigan Bay: monitoring 2005-2007 (Pesante G, Evans PGH, Anderwald P, Powell D, McMath M (2008a) Connectivity of bottlenose dolphins in Wales: North Wales photo-monitoring. CCW Marine Monitoring Report No. 62. Countryside Council for Wales, Bangor)
  • Connectivity of bottlenose dolphins in Wales: North Wales photo-monitoring (Pesante G, Evans PGH, Baines ME, McMath M (2008b) Abundance and Life History Parameters of Bottlenose Dolphin in Cardigan Bay: Monitoring 2005-2007. CCW Marine Monitoring Report No. 61. Countryside Council for Wales, Bangor)

Risso’s Dolphin

Eisfeld, S.M. and Lott, R. (2013). Risso’s dolphins in North Wales. CCW Contract Science Report No.1021. 26 pp. (Contact NRW customer hub for access).

Risso’s dolphin surveys undertaken between 1997-2016 around Ynys Enlli / Bardsey Island and the Llŷn Peninsula (Eisfeld-Pierantonio & James, 2018 (NRW Evidence Report No. 261)) You will need Whale and Dolphin Conservation’s permission to reproduce or use these data.

Other sources

Cetacean data for Welsh waters are also collected and held by:

Further information and data should be requested directly from the group or organisation.

Large Scale & Collaborative Projects (All cetacean species)

Small cetaceans in European Atlantic waters and the North Sea (SCANS) is a series of large-scale surveys for cetaceans in European Atlantic waters, initiated in 1994. The latest SCANS survey was SCANS IV in 2022. A previous survey, SCANS III was held in 2016, SCANS II in 2005/2007, and SCANS in 1994.

Joint Cetacean data programme (JDCP) is a platform and tools developed to improve collection, collation and accessibility of cetacean data. It comprises three interlinked web pages: the JNCC Information Hub the JCDP Data Portal (hosted on the International Council for the Exploration of the Sea (ICES) Data Centre); and the JCDP Metadata Catalogue (hosted on the ICES GeoNetwork). It provides data collectors, custodians, and users with the ability to upload and access cetacean survey data and associated information on how and why these data were collected, as well as information to support the standardised collection and management of JCDP-compliant cetacean survey data.

The ObSERVE survey programme provides improved knowledge of protected offshore species and sensitive habitats through high quality, state-of-the-art data collection across Ireland's Exclusive Economic Zone (EEZ).

The Atlas of Cetacean distribution in north-west European waters published in 2003 by the JNCC provides an account and snapshot of the distribution of all 28 cetacean species that are known certainly to have occurred in the waters off north-west Europe in the 25 years prior to its publication. It remains a useful, if not dated, resource. Slightly more recent information for some species is also available in JNCC Report No. 517 Revised Phase III Data Analysis of Joint Cetacean Protocol Data Resources published in 2016, and UK level distribution maps can be found here: Distribution maps of cetacean and seabird populations in the North‐East Atlantic - Waggitt - 2020 - Journal of Applied Ecology - Wiley Online Library. More contemporary analyses are underway via the POSEIDON project.

Grey Seals

Photo-ID data

We and our partners conducted grey seal surveys and collected photo-identification images of seals from across Wales (DataMapWales) and is described in the following report: Langley et al. (2018) EIRPHOT: A critical assessment of Wales’ grey seal (Halichoerus grypus) photo-identification database. Results are also published in Langley et al 2020 Site use and connectivity of female grey seals (Halichoerus grypus) around Wales. The data provide capture histories of individual seals yielding information on site fidelity, site connectivity and survival. The data can be supplied under licence and you should follow the procedures on the Accessing Our Data page of our website if you want to request data.

Surveys and pupping data

Seals spend the majority of their time at sea. Estimates of seal density at sea is therefore an important consideration in environmental assessments as provided in Carter et al. 2025 At-sea distribution of seals on the Northwest European Shelf: Towards transboundary conservation and management.

Additionally, datasets from Carter et al. detailing at-sea distribution for grey and harbour seals on the NW European Shelf are provided for download.

Data on the number and distribution of grey seals in Wales (including low tide haul-out counts, pupping site distribution and pup counts) have been collected over several decades and at multiple locations in Wales including Skomer, Ynys Dewi / Ramsey Island, Ynys Enlli/Bardsey Island, north and west Wales. The many reports arising from this work are listed in the NRW Data Discovery and marine publications pages of our website.

NRW recently commissioned the Sea Mammal Research Unit (SMRU), University of St Andrews, to conduct a comprehensive synoptic survey of the coast of the Wales to obtain a count of seals hauled out during the August survey window in 2023. The data collected is presented in evidence report 865: Census of seals in Wales using aerial surveys.

Our data feeds into the wider UK programme coordinated by the Sea Mammal Research Unit (SMRU). This is reviewed by the NERC Special Committee on Seals, which provides estimates for the UK seal populations.

North Wales

The most recent grey seal pup census providing pup production and distribution estimates in north Wales (between Aberystwyth and the Dee Estuary) was carried out in 2017.

Further datasets can be requested from:

  • Hilbre Bird Observatory (for West Hoyle Sandbank in the Dee estuary)
  • RSPB and Bardsey Bird and Field Observatory (for weekly low tide counts of grey seals at Ynys Enlli / Bardsey Island)
  • North Wales Wildlife Trust (regular low tide counts of grey seals at the Little Orme near Llandudno)

Pembrokeshire

Although dated, a key dataset for the grey seals in West Wales/Pembrokeshire is still Baines et al., 1995. The West Wales grey seal census 1992-1994. CCW Contract Science Report No. 131. Countryside Council for Wales, Bangor. For access to this report contact the NRW customer hub.

As part of our past SAC monitoring commissioned work, a summary of pup counts in north Pembrokeshire is provided in: Strong et al., 2006. Pembrokeshire marine SAC grey seal monitoring 2005. CCW Marine Monitoring Report No: 26; redacted version. 51pp.

There are a number of more recent reports that present data from pup counts around Pembrokeshire: View our reports on the marine publications pages of our website.

Grey seal pup monitoring has beenundertake(since the 1970s on Skomer, nowthe Skomer Marine Conservation Zone (MCZ), which comprises of Skomer Island and the mainland (Marloes). Comprehensive data is available through the annual reports on our marine publications pages. 

A synopsis of grey seal pupping data up to 2016 from Ynys Dewi / Ramsey Island is given here: Morgan LH, Morris CW, Stringell TB. 2018. Grey Seal Pupping Phenology on Ynys Dewi / Ramsey Island, Pembrokeshire. NRW Evidence Report No: 156, 22 pp, Natural Resources Wales, Bangor. Data from Ramsey Island can be requested from the RSPB.

Designated Sites and Protected Species Data

Habitats Regulations: SAC maps and data for Annex II marine mammal features

There are three marine mammal species listed under Annex II of the EU Habitats Regulations that are designated features of marine Special Areas of Conservation (SACs) in Wales:

  • Bottlenose dolphin (Tursiops truncatus)
  • Harbour porpoise (Phocoena phocoena)
  • Grey seal (Halichoerus grypus)

Find out more information about these species, including where they are present as a feature of a SAC.

See our conservation advice packages and condition assessments in relation to bottlenose dolphin and grey seal.

Habitats Regulations: Regulation 9A reporting

Habitat Regulations 9A Report for Wales 2019 - 2024 were published in January 2026. The Habitats Regulations 9A report represents Wales’ first country-level assessment under Regulation 9A of the Conservation of Habitats and Species Regulations 2017 (as amended in Wales). It was prepared on behalf of the Welsh Government, and integrates information on habitats, non-bird species and birds, providing a comprehensive account of their trends, pressures and conservation measures.

UK level reports for Regulation 9A (2019-2024) can be found at the following websites: 

Previous UK-level Article 12 and Article 17 reports were published by the Joint Nature Conservation Committee (JNCC).

Other marine mammal data

Management units for cetaceans in UK waters (IAMMWG, 2015) sets out Management Units for the seven most common cetacean species in UK waters. Updated estimated abundance figures and boundaries for each management unit are provided in Inter-Agency Marine Mammal Working Group (2023): Review of Management Unit boundaries for cetaceans in UK waters (2023) | JNCC Resource Hub. Note this uses older (2016) SCANS III and ObSERVE estimates – an update is in progress.

The harbour porpoise is also listed on the Oslo and Paris Commissions (OSPAR) list of threatened and declining habitats and species. The OSPAR Quality Status Reports (2023), provide a wealth of information and data on cetacean distribution and abundance, grey seal pup production, seal distribution, and estimates of bycatch: All Indicator Assessments - OSPAR-OAP (Prod).

The International Council for the Exploration of the Sea (ICES) provide the most up to date information on regional (NE Atlantic and adjacent seas) bycatch of protected species, including marine mammals: Item - Working Group on Bycatch of Protected Species (WGBYC) 2025 Report - International Council for the Exploration of the Sea - Figshare.

Marine birds

Marine bird data

European Seabirds at Sea includes data on abundance and distribution of seabirds at a UK and north-west European level. The Marine Atlas Modelled Distributions and Abundance of Cetaceans and Seabirds of Wales and Surrounding Waters data and report produced in 2023 as well as the NRW webpage Mapping environmental considerations for marine planning includes data on abundance and distribution of seabirds at a Welsh wide level.

The Seabird Monitoring Programme (SMP) is an ongoing annual monitoring programme, established in 1986, of 25 species of seabird that regularly breed in Britain and Ireland. The data includes information on seabird colonies in Wales. SMP's annual reports documents trends in population numbers and breeding success, productivity, survival and diet of breeding seabirds.

The SMP also includes periodic breeding seabird censuses to:

  • assess seabird population health and conservation status
  • the effects of climate change on marine environments
  • inform marine planning

The current census, Seabirds Count, was being coordinated by JNCC and survey work began in 2015, with results published on 16th November 2023.

The Wetland Bird Survey (WeBs) and Non-Estuarine Waterbird Survey (NEWS) are co-ordinated by the British Trust for Ornithology. WeBS involves regular counts of wintering, non-breeding waterbirds in coastal, wetland and intertidal areas. NEWS completes periodic counts (approximately decadal) of non-estuarine sections of coastline not covered by WeBS.

These datasets can usefully inform scoping studies for casework applications, though further site-specific data will usually be required to inform environmental assessments.

Designated and protected marine birds

Birds Directive Special Protection Areas

Some marine bird species and waterfowl are designated features of Special Protection Areas (SPAs) in Wales, as established under the Birds Directive.

View the boundaries of SPAs in Wales on DataMapWales. You can find out individual site names by clicking on the interactive map and can download site boundary data from the website.

Find out more information on marine and coastal SPAs in Wales.

Sites of Special Scientific Interest

Marine birds in Wales may also be protected as features of Sites of Special Scientific Interest (SSSI). View SSSI boundaries for sites in Wales. You can find out individual site names by clicking on the interactive map as well as download the site boundary data.

Use the protected sites search to find out more on the protected features of individual SSSIs.

Other marine bird data

Find out more about the populations of marine birds in Wales from the report State of Birds in Wales 2022.



Fish data

Data available for protected, designated or listed fish species

Protected fish species

Information on fish species protected by law is available here:

Many of these species occur in Welsh marine waters during some or all of their life cycle.

Fish species of SACs and Ramsar sites

There are four diadromous fish species (these are species that spend portions of their life cycle partially in freshwater and partly in salt water) listed under Annex II of the EU Habitats Directive that are designated features of marine SACs in Wales: 

  • Sea lamprey Petromyzon marinus 
    • Severn Estuary SAC
    • Carmarthen Bay & Estuaries SAC
    • Pembrokeshire Marine SAC
    • Cardigan Bay SAC
    • Dee Estuary SAC

  • River lamprey Lampetra fluviatilis
    • Severn Estuary SAC
    • Carmarthen Bay & Estuaries SAC
    • Pembrokeshire Marine SAC
    • Cardigan Bay SAC
    • Dee Estuary SAC

  • Allis shad Alosa alosa
    • Carmarthen Bay & Estuaries SAC
    • Pembrokeshire Marine SAC

  • Twaite shad Alosa fallax 
    • Severn Estuary SAC
    • Carmarthen Bay & Estuaries SAC
    • Pembrokeshire Marine SAC

The Severn Estuary Ramsar site also has diadromous fish species as a qualifying interest of the site; this includes the designated Annex II fish species of the overlapping SAC but also other migratory fish species Atlantic salmon Salmo salar, sea trout Salmo trutta and European eel Anguilla anguilla. 

The migratory fish assemblage and estuarine fish assemblage of the Severn Estuary are also sub features of the Estuaries feature of the Severn Estuary SAC, and many of the Annex I habitat features of marine SACs in Wales have a conservation objective for the biological communities of the feature.

Rivers which are SACs and have diadromous fish species (Atlantic salmon, sea lamprey, river lamprey, allis shad and twaite shad) as qualifying interest features are the River Wye SAC, River Usk SAC, River Tywi SAC, Cleddau Rivers SAC, River Teifi SAC, Afon Eden – Cors Goch Trawsfynydd SAC, Afon Gwyrfai a Llyn Cwellyn SAC and River Dee and Bala Lake SAC. These species will spend a portion of their life in the marine environment and so may be relevant to consider for marine activities or developments.

The boundaries of the SACs and Ramsar sites can be viewed and downloaded here:

Our conservation advice for the relevant sites with diadromous fish species as features is provided below, with further detail, including site maps, available at Natural Resources Wales / Find protected areas of land and sea.

Standard data forms for each site can be found on the JNCC website.

Our condition assessments for marine SACs with diadromous fish features are provided below:

Wales’ first country-level assessment of the national status of these species under Regulation 9A of the Conservation of Habitats and Species Regulations 2017 (as amended in Wales) is available here, and includes assessments and distribution maps for each of the Annex II diadromous fish species:

Fish species of SSSIs

There are seven diadromous fish species in Wales that are designated as features of marine Sites of Special Scientific Interest (SSSI) in Wales. 

  • Sea lamprey Petromyzon marinus 
    • Severn Estuary SSSI
    • Dee Estuary SSSI
    • Afon Teifi SSSI
    • River Dee SSSI

  • River lamprey Lampetra fluviatilis
    • Severn Estuary SSSI
    • Dee Estuary SSSI
    • Afon Teifi SSSI
    • River Dee SSSI

  • Allis shad Alosa alosa
    • Severn Estuary SSSI
    • Pembrey Coast SSSI
    • Taf Estuary SSSI
    • Afon Tywi SSSI

  • Twaite shad Alosa fallax 
    • Severn Estuary SSSI
    • Pembrey Coast SSSI
    • Taf Estuary SSSI
    • Afon Tywi SSSI

  • European smelt Osmerus eperlanus
    • Dee Estuary SSSI
    • River Dee SSSI
    • Milford Haven Waterway SSSI

  • Atlantic salmon Salmo salar
    • Severn Estuary SSSI
    • River Teifi SSSI
    • River Dee SSSI

  • European eel Anguilla anguilla
    • Severn Estuary SSSI

The boundaries of the SSSIs can be viewed and downloaded here:

Citations, maps, management schemes and potentially damaging operations for the SSSIs are available at:

Fish species in Wales are also designated as features of freshwater and riverine Sites of Special Scientific Interest (SSSI) in Wales. These are generally the same as the river SACs listed in Section 5.1.2 above.

Fish species listed under other legislation

There are several diadromous and marine fish species listed on Section 7 of the Environment (Wales) Act 2016 that are relevant to marine and estuarine areas of Wales (listed under ‘fish’ and ‘marine’). Some of these are also on the OSPAR list of threatened and declining habitats and species.

Other data available for diadromous fish species

Species distribution data is available here:

There is additional information on diadromous fish species distributions from our freshwater surveys and monitoring available here:

NRW Freshwater Fish Surveys | DataMapWales 

NRW’s salmon and sea trout plan of action is available here:

Fisheries data and stock assessments for some diadromous fish species are available here:

SoNaRR 2025 is an assessment of the status and trends of natural resources in Wales, and includes detail on many diadromous fish species populations:

If these data do not meet your specific data requirements, you may need to seek specialist advice from NRW for a particular locality or species and search other data sources such as academic and grey literature.

Other data available for estuarine and marine fish species (including elasmobranchs)

Species distribution data for estuarine and marine fish is available here:

There is information on estuarine fish species presence and abundance from our WFD transitional fish surveys. Find out more about NRW Marine Fish Surveys on DataMapWales.

Sampling is undertaken using seine and fyke nets, beam trawls and otter trawls. Maps showing WFD status assessments for waterbodies in Wales can be viewed online using: Water Watch Wales and downloaded at: Water Framework Directive (WFD) Regulations Cycle 3 Classification | DataMapWales. 

SoNaRR 2025 is an assessment of the status and trends of natural resources in Wales, and includes detail on many estuarine and marine fish species populations:

There are several marine fish datasets that are produced by others and are available from the sources described below. These data have been collected for specific fishery assessment purposes and may not meet your specific data requirements, so you may need to seek specialist advice for a particular locality or species. Also, these data do not provide a complete picture for marine fish in Wales and consideration should be given to the methods used, areas surveyed and timing of the surveys.

Fisheries data and stock assessments for some marine fish species are available from International Council for the Exploration of the Seas (ICES) here:

Sea fisheries statistics including landings for the UK are available from the MMO here:

The Centre for Environment, Fisheries and Aquaculture Science (Cefas), in partnership with other organisations, routinely collect data on fish in the Celtic and Irish Seas, including Welsh waters. These data can be found or requested via the Cefas Data Portal.

For information on spawning and nursey grounds of selected fish species in UK waters the following data and reports are of relevance:

Other sources of data are:

  • Database of Trawl Surveys (DATRAS) which stores data primarily from bottom trawl fish surveys coordinated by ICES expert groups with survey data covering the Irish and Celtic Seas.
  • MEDIN marine data portal where you can search for fisheries and aquaculture datasets under ‘data theme’ in the advanced search. 

If these data do not meet your specific data requirements, you may need to seek specialist advice from NRW for a particular locality or species and search other data sources such as academic and grey literature.


Cockle stock assessments

We undertake, or commission, cockle stock surveys in spring and autumn in the Dee Estuary to assess cockle stocks and inform management decisions about commercial shellfish quotas and winter bird food requirements. Welsh Government manage other public cockle fisheries in Wales including the Burry Inlet and Three Rivers and can be contacted via Sea and intertidal fisheries (GOV.WALES).


Turtles

Six of the seven species of marine turtle have been recorded in UK waters, five of which are afforded strict protection under Schedule 2 of the Habitats Regulations (Annex IV of the Habitats Directive):

    • Leatherback turtle (Dermochelys coriacea)
    • Loggerhead turtle (Caretta caretta)
    • Hawksbill turtle (Eretmochelys imbricata)
    • Kemp’s ridley turtle (Lepidochelys kempii)
    • Green turtle (Chelonia mydas)

The sixth species, the olive ridley (Lepidochelys olivacea), and live stranded in the Menai Strait, North Wales in November 2016; this species is not listed on Annex IV of the Habitats Directive. The seventh species of marine turtle is the flatback turtle (Natator depressus), endemic to Australasian waters.

Only the leatherback turtle is considered to be a regular (but rare) visitor. The other five species are considered vagrant in UK waters.

View and download the UK-level reports for the Habitats Regulations 9A Report for Wales 2019-2024: UK marine species data reporting for the five species listed above. The leatherback turtle and loggerhead turtle are also listed under:

The TURTLE database managed by Marine Environmental Monitoring (MEM) keeps a record of all sightings and strandings of turtles in the British Isles and Republic of Ireland where you can download annual summary reports.

All marine turtle records from the database are updated annually to the NBN Atlas Wales.

Accessing our data

Find out more about how to access our data.

Other data you may need

This is not a complete list of available marine ecological datasets for Wales.

Depending on your data and information requirements, you may need to:

    • look for data, surveys and reports produced and held by other organisations, companies and researchers
    • commission the collection of additional data

It is your responsibility to clarify and source the data and information you need to support your application.

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