4f4c4942-4343-5764-6473-313039383931 English NRW_DS121633 Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-03-03T16:20:39.638Z NRW 1.0 wel Latitude and Longitude (EPSG::4326) Acoustic Monitoring of the Extent of the North Llyn Modiolus Reef Acoustic Monitoring of the Extent of the North Llyn Modiolus Reef Gwaith monitro acwstig ar y riff Modiolus yng Ngogledd Llyn 1999 CCW Modiolus monitoring trial survey off North Pen LLyn Side-scan sonar monitoring of the North Llyn Modiolus reef 2013-04-01 NRW_DS109891 Biogenic horse mussel (Modiolus Modiolus) reef is an important feature of the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). The reef has high biodiversity and is vulnerable to anthropogenic activities, such as benthic fishing. The mussel reef forms an undulating surface that is significantly different to the surrounding seabed and therefore acoustic monitoring methods can be used to monitor changes in extent and identity areas of potential damage. Work is carried out on the north Llyn horse mussel reef in Pen Llyn a'r Sarnau jointly by Countryside Council for Wales (CCW) and University of Wales Bangor. The purpose of this data capture was to: - Measure extent and temporal changes within the of the Modiolus reef in the Pen Llyn a'r Sarnau SAC. - Investigate the health of the reef and for signs of anthropogenic activity within the area. An area approximately 10km by 6km, adjacent to the Pen Llyn coast, south-west of Porth Dinllaen, approximately 1.5km off shore was surveyed. All data is processed to reduce errors (e.g. positional corrections). Acoustic data is subject to ground-truthing using drop down videos captured as part of a separate project. As of April 1st, 2013 data is held and managed by Natural Resources Wales (NRW). Biogenic horse mussel (Modiolus Modiolus) reef is an important feature of the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). The reef has high biodiversity and is vulnerable to anthropogenic activities, such as benthic fishing. The mussel reef forms an undulating surface that is significantly different to the surrounding seabed and therefore acoustic monitoring methods can be used to monitor changes in extent and identity areas of potential damage. Work is carried out on the north Llyn horse mussel reef in Pen Llyn a'r Sarnau jointly by Countryside Council for Wales (CCW) and University of Wales Bangor. The purpose of this data capture was to: - Measure extent and temporal changes within the of the Modiolus reef in the Pen Llyn a'r Sarnau SAC. - Investigate the health of the reef and for signs of anthropogenic activity within the area. An area approximately 10km by 6km, adjacent to the Pen Llyn coast, south-west of Porth Dinllaen, approximately 1.5km off shore was surveyed. All data is processed to reduce errors (e.g. positional corrections). Acoustic data is subject to ground-truthing using drop down videos captured as part of a separate project. As of April 1st, 2013 data is held and managed by Natural Resources Wales (NRW). University of Wales Bangor Bangor University, Bangor, Gwynedd, LL57 2DG hr@bangor.ac.uk http://www.bangor.ac.uk Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en University of Wales Bangor Bangor University, Bangor, Gwynedd, LL57 2DG hr@bangor.ac.uk http://www.bangor.ac.uk Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Countryside Council for Wales (CCW) Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk/splash?orig=/ University of Wales, Bangor. School of Ocean Sciences Bangor, Gwynedd, LL57 2DG oss011@bangor.ac.uk http://www.bangor.ac.uk Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Habitats and biotopes GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme horse mussel Special Area of Conservation Monitoring Pen Llyn a'r Sarnau cSAC multibeam biogenic reef modiolus modiolus acoustic observation (acoustic monitoring) sidescan sonar NRW Thesaurus 2025-01-08 geonetwork.thesaurus.local.theme.converted_nrw-keywords Side-scan sonar Shellfish abundance and biomass in water bodies SeaDataNet Parameter Discovery Vocabulary 2024-06-19 geonetwork.thesaurus.external.theme.rdf+xml This data is jointly owned by NRW and the University of Wales, Bangor. There are no access restrictions to this data. NRW may release, publish or disseminate it freely. no limitations © CNC/NRW and Bangor University 2013 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 the copyright of NRW / Bangor University 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 imageryBaseMapsEarthCover SeaVoX Vertical Co-ordinate Coverages 2021-01-06 benthic boundary layer Irish Sea Cardigan Bay Tremadog Bay GWYNEDD - GWYNEDD -4.71395825 -4.58178064 52.90351843 52.98355757 1998-07-07 2013-04-01 -25 -45 Please see CCW Marine Monitoring Report no.50. 01/07/1998 side-scan sonar monitoring trial . Data is also available online at http://www.ukdmos.org/v_ukdmos_edios/result.asp The establishment of a programme of surveillance and monitoring for judging the condition of the features of Pen Llyn a'r Sarnau cSAC : 1. Progress to March 2001 Review of sidescan sonar results from North Llyn Geographic Information System [A] All raster images held as tif files. [B] Extent of the Modiolus reef held as MapInfo file. 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 Side scan-sonar data is captured from either the CCW research vessel (R.V. Pedryn) or the University research vessel (R.V. Price Madog) using a CMAX CM800 sidescan sonar. Multibeam has been captured from the University research vessel (R.V. Prince Madog) in 2008 using a Kongsberg EM 3002 Dual Head multibeam echo sounder. The reef and surrounding area was also multibeamed as part of the HABMAP project in 2005 on board the Irish Marine Institute's 'Celtic Voyager' using a simrad EM1002 95KHz multibeam Echosounder. Concurrently, a sub-bottom profiling system, using a broadband high-resolution 'boomer' was also used in the same area. All data is processed and incorporated into MapInfo GIS. Analysis of the data is written up as unpublished MSc projects at the University of Wales Bangor. Project is carried out in conjunction with the Across Wales drop-down video project. Additional projects have been carried out to study the anthropogenic effects discovered at the site. Side scan-sonar data is captured from either the CCW research vessel (R.V. Pedryn) or the University research vessel (R.V. Price Madog) using a CMAX CM800 sidescan sonar. Multibeam has been captured from the University research vessel (R.V. Prince Madog) in 2008 using a Kongsberg EM 3002 Dual Head multibeam echo sounder. The reef and surrounding area was also multibeamed as part of the HABMAP project in 2005 on board the Irish Marine Institute's 'Celtic Voyager' using a simrad EM1002 95KHz multibeam Echosounder. Concurrently, a sub-bottom profiling system, using a broadband high-resolution 'boomer' was also used in the same area. All data is processed and incorporated into MapInfo GIS. Analysis of the data is written up as unpublished MSc projects at the University of Wales Bangor. Project is carried out in conjunction with the Across Wales drop-down video project. Additional projects have been carried out to study the anthropogenic effects discovered at the site.