4f4c4942-4343-5764-6473-313039383233 English Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-03-03T14:49:09.263Z NRW 1.0 wel British National Grid (EPSG::27700) Shellfish Stocks, Oystercatcher and Knot (bird) Modelling Data for the Dee Estuary, Traeth Lafan and the Burry Inlet and Three Rivers, Phase 1 (1993-2001) Shellfish Stocks, Oystercatcher and Knot (bird) Modelling Data for the Dee Estuary, Traeth Lafan and the Burry Inlet and Three Rivers, Phase 1 (1993-2001) Data rhagfynegol yn ymwneud a chregynbysgod, piod mor a phibyddion yr aber (adar) ar gyfer Afon Dyfrdwy, Traeth Lafan a Phorth Tywyn a'r Tair Afon, Cam 1 (1993-2001). Marine monitoring project: Modelling oystercatchers and their food on the Dee estuary, Traeth Lafan and Burry Inlet SPA to inform target setting and site management (phase 1). 2003-04-01 NRW_DS109823 The Dee, Traeth Lafan and Burry Inlet are designated Special Protection Areas (SPAs) for nationally and internationally important populations of wintering wildfowl and waders. In order to set conservation objectives and assess the sites for Favourable Conservation Status, information is required on numbers of birds using the sites and the food supplies they require to survive the winter and attain adequate body condition for Spring Migration. The three SPAs also support economically important cockle fisheries that may affect oystercatchers directly, by removing some of the food available to them and, indirectly, by displacing them from the best cockle beds to less suitable feeding areas. This is phase 1 of the project that will assess and use existing data to run an Individual Behaviour-based Model (IBM) to answer key questions relating to target setting, condition monitoring and management of each of the three sites. There were two main objectives to the project. The first to assess the power of existing surveys to detect change in the cockle populations at each site and recommend possible improvements. The second objective was to determine how each site was used by the populations of oystercatchers that roosted there. The models can be used to establish the target baseline quality habitats in terms of invertebrate populations but also in terms of the ability of the site to support the bird populations for which it was designated and therefore establish parameters for longer term monitoring and to establish whether it is in favourable conservation status. The Dee, Traeth Lafan and Burry Inlet are designated Special Protection Areas (SPAs) for nationally and internationally important populations of wintering wildfowl and waders. In order to set conservation objectives and assess the sites for Favourable Conservation Status, information is required on numbers of birds using the sites and the food supplies they require to survive the winter and attain adequate body condition for Spring Migration. The three SPAs also support economically important cockle fisheries that may affect oystercatchers directly, by removing some of the food available to them and, indirectly, by displacing them from the best cockle beds to less suitable feeding areas. This is phase 1 of the project that will assess and use existing data to run an Individual Behaviour-based Model (IBM) to answer key questions relating to target setting, condition monitoring and management of each of the three sites. There were two main objectives to the project. The first to assess the power of existing surveys to detect change in the cockle populations at each site and recommend possible improvements. The second objective was to determine how each site was used by the populations of oystercatchers that roosted there. The models can be used to establish the target baseline quality habitats in terms of invertebrate populations but also in terms of the ability of the site to support the bird populations for which it was designated and therefore establish parameters for longer term monitoring and to establish whether it is in favourable conservation status. Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Various Enquiries Unit, Maes y Fynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk/splash?orig=/ North Western And North Wales Sea Fisheries Committee = Pwllgor Pysgodfeydd Mor Gogledd Orllewin Lloegr a Gogledd Cymru 1 Preston Street, Carnforth, Lancashire, LA5 9BY, England office@nwnwsfc.org http://www.nwnwsfc.org/ British Trust for Ornithology (BTO) The Nunnery, Thetford, Norfolk, IP24 2PU, England info@bto.org http://www.bto.org/ Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme haematopus ostralegus unionidae Burry Inlet shellfish cockles cockle beds Dee estuary Mersey estuary Lafan sands (Lavan sands)(Traeth Lafan) mussels common mussel Morecambe Bay mytilus edulis Ribble estuary mussel beds oystercatchers marine monitoring (see also marine surveys) Special Protection Areas (SPAs) (see also proposed Special Protection Area pSPA) cerastoderma edule (previously known as cardium edule) environmental modelling NRW Thesaurus 2025-01-08 geonetwork.thesaurus.local.theme.converted_nrw-keywords Bird taxonomy-related abundance per unit area of surface Shellfish abundance and biomass in water bodies SeaDataNet Parameter Discovery Vocabulary 2024-06-19 geonetwork.thesaurus.external.theme.rdf+xml There are no access restrictions to this data. NRW may release, publish or disseminate it freely. no limitations © CNC/NRW 2003 There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source. English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 benthic boundary layer Wales (WLS) -5.777741 -2.608865 51.240829 53.513067 1986-04-01 2001-02-28 Modelling oystercatchers and their food on the Dee estuary, Traeth Lafan and Burry Inlet SPA to inform target setting and site management : phase 1 Documents [A] Data on cockle density spreadsheet format (MS Excel) [B] GIS data (ArcView, MapInfo) [C] Wetland Birds Survey (WeBS) counts (Txt Files, MS Excel spreadsheet, introduction MS Word) Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services 2010-12-08 This dataset has not been assessed for conformance to the referenced INSPIRE regulation. false The Centre for Ecology and Hydrology (CEH) developed and tested and an Individual Behaviour-based Model (IBM) that predicts the effects of changes in the food supply and the amount of disturbance on the body condition and the over-winter survival rate of the oystercatchers. The model requires information on bird foraging behaviour together with site-specific data on bird numbers, and the size and distribution of cockle and mussel stocks. Cockle data was collated from the Environment Agency (EA), North West and North Wales Sea Fisheries Committee (NW and NWSFC), Centre for Environment, Fisheries and Aquaculture Science (CEFAS). Bird data was collated from the British Trust for Ornithology (BTO). Other information required to run the model, includes details of ash free weight, tide times, mean daily temperature and information on shellfish disturbance from the fisheries. Cockle counts: Dee estuary, Traeth Lafan, Burry inlet, Wales Oystercatcher counts: Dee estuary, Traeth Lafan, Burry Inlet, Alt Estuary, Mersey Estuary, Morecambe Bay, Ribble Estuary Cockle data from the Dee Estuary 1997-2002 Cockle data from Traeth Lafan 1994 - 2000 Cockle data from Burry Inlet 1993 - 2001 Oystercatcher counts (and counts for other bird species) Apr 1986 - Feb 2001 (monthly) The Centre for Ecology and Hydrology (CEH) developed and tested and an Individual Behaviour-based Model (IBM) that predicts the effects of changes in the food supply and the amount of disturbance on the body condition and the over-winter survival rate of the oystercatchers. The model requires information on bird foraging behaviour together with site-specific data on bird numbers, and the size and distribution of cockle and mussel stocks. Cockle data was collated from the Environment Agency (EA), North West and North Wales Sea Fisheries Committee (NW and NWSFC), Centre for Environment, Fisheries and Aquaculture Science (CEFAS). Bird data was collated from the British Trust for Ornithology (BTO). Other information required to run the model, includes details of ash free weight, tide times, mean daily temperature and information on shellfish disturbance from the fisheries. Cockle counts: Dee estuary, Traeth Lafan, Burry inlet, Wales Oystercatcher counts: Dee estuary, Traeth Lafan, Burry Inlet, Alt Estuary, Mersey Estuary, Morecambe Bay, Ribble Estuary Cockle data from the Dee Estuary 1997-2002 Cockle data from Traeth Lafan 1994 - 2000 Cockle data from Burry Inlet 1993 - 2001 Oystercatcher counts (and counts for other bird species) Apr 1986 - Feb 2001 (monthly)