4f4c4942-4343-5764-6473-313135323137 English NRW_DS116344 Master Reference Data Team Natural Resources Wales, Maes y Fynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk/splash?orig=/ 2026-10-01T14:09:35.124Z NRW 1.0 wel utf8 British National Grid (EPSG::27700) Llyn Tegid and Llyn Arenig Fawr hydroacoustic and Gwyniad surveys 2012 Llyn Tegid and Llyn Arenig Fawr hydroacoustic and Gwyniad surveys 2012 Arolygon hydroacwstig ac arolygon o wyniaid Llyn Tegid a Llyn Arenig Fawr 2012 Gwyniad Hydroacoustic and Gill Netting Survey of Llyn Arenig Fawr 2012- CCW Science Report 1013 CCW000800000000I Gwyniad Hydroaccoustic Survey of Llyn Tegid 2012 - CCW Science Report 1012 CCW000800000000G 2012-08-07 NRW_DS115217 http://naturalresources.wales/ The gwyniad (Coregonus lavaretus) population of Llyn Tegid has, for a number of years, been considered threatened by deteriorating environmental conditions, particularly those associated with eutrophication. This dataset contains the results of a project investigating the environmental factors affecting the species and its habitat. Attempts have been made since 2003 to establish a refuge population through the translocation of gwyniad to Llyn Arenig Fawr. The purpose of this study was to assess the status of gwyniad and its habitat in both Llyn Tegid, which supports the native population, and Llyn Arenig Fawr, which supports the introduced population. The gwyniad (Coregonus lavaretus) population of Llyn Tegid has, for a number of years, been considered threatened by deteriorating environmental conditions, particularly those associated with eutrophication. This dataset contains the results of a project investigating the environmental factors affecting the species and its habitat. Attempts have been made since 2003 to establish a refuge population through the translocation of gwyniad to Llyn Arenig Fawr. The purpose of this study was to assess the status of gwyniad and its habitat in both Llyn Tegid, which supports the native population, and Llyn Arenig Fawr, which supports the introduced population. 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 Centre for Ecology and Hydrology (CEH) Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, Wales enquiries@ceh.ac.uk http://www.ceh.ac.uk/ 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 gwyniad (freshwater whitefish) coregonus lavaretus hydroacoustic Llyn Tegid secchi depth Llyn Arenig Fawr oxygen profile marine and freshwater inventory temperature profile NRW Thesaurus 2026-08-27 geonetwork.thesaurus.local.theme.converted_nrw-keywords Temperature of the water column Fish taxonomy-related counts 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 2012. 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. Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Open Government Licence English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 water column GWYNEDD - GWYNEDD -3.66161429 -3.58302308 52.85964672 52.91223083 2012-08-06 2012-08-07 Ffynnon Reference Number: DCT-13-068971 / DCT-13-068914: Llyn Tegid Hydroacoustic Survey 2012 I. Winfield., J. Fletcher., and J. James., CCW Contract Science Report No. 1012 Ffynnon Reference Number: DCT-13-068851 / DCT-13-069046: Llyn Arenig Fawr Gwyniad Survey 2012 Winfield., J. Fletcher., and J. James., CCW Contract Science Report No. 1013 Llyn Arenig Fawr Gwyniad survey 2009 Llyn Tegid hydroacoustic survey 2012 Binary Unknown Oxygen and temperature profiles in Excel (.xls) format; Raw echo sounder acquisition data (.dt4); Species data in Excel (.xls) format Database Unknown Recorder 6 species datasets Delimited Unknown Echoview laboratory analysis data in CSV format Image Unknown JPEG images Documents Unknown Final reports in Microsoft Word and Adobe PDF formats 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 At Llyn Tegid, hydroacoustic surveys were conducted alongside measurements of associated environmental variables, including temperature and oxygen profiles, and Secchi disc readings. The survey utilised the standardised protocol for the assessment and monitoring of whitefish populations (Bean, 2003; JNCC, 2005), with two minor deviations. Firstly, the fish length-target strength relationship described by Love (1971) was used instead of that proposed by Foote (1987) to facilitate wider comparison with other studies. Secondly, a vessel speed of 2.0 m s⁻¹ was adopted as the target mean speed rather than as an absolute upper limit. Equivalent data collection was also undertaken at Llyn Arenig Fawr, including a standardised gill-net survey. This dataset forms part of the continuation of the Llyn Tegid Hydroacoustic Surveys and Gwyniad Translocations 2004-2009 project. At Llyn Tegid, hydroacoustic surveys were conducted alongside measurements of associated environmental variables, including temperature and oxygen profiles, and Secchi disc readings. The survey utilised the standardised protocol for the assessment and monitoring of whitefish populations (Bean, 2003; JNCC, 2005), with two minor deviations. Firstly, the fish length-target strength relationship described by Love (1971) was used instead of that proposed by Foote (1987) to facilitate wider comparison with other studies. Secondly, a vessel speed of 2.0 m s⁻¹ was adopted as the target mean speed rather than as an absolute upper limit. Equivalent data collection was also undertaken at Llyn Arenig Fawr, including a standardised gill-net survey. This dataset forms part of the continuation of the Llyn Tegid Hydroacoustic Surveys and Gwyniad Translocations 2004-2009 project.