4f4c4942-4343-5764-6473-313136373235 English Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2025-03-07T17:31:25.301Z NRW 1.0 wel British National Grid (EPSG::27700) Freshwater pearl mussel (Margaritifera margaritifera) larval encystment of host fish species on the Afon Eden – Cors Goch Trawsfynydd Special Area of Conservation (SAC) Freshwater pearl mussel (Margaritifera margaritifera) larval encystment of host fish species on the Afon Eden – Cors Goch Trawsfynydd Special Area of Conservation (SAC) Larfaod codennog Fisglod Perl Dŵr Croyw (Margaritifera margaritifera) rywogaeth bysgodyn lletyol ar yr Afon Eden - Ardal Cadwraeth Arbennig (ACA) Cors Goch Trawsfynydd 2016-07-31 NRW_DS116725 The freshwater pearl mussel (Margaritifera margaritifera) is protected under several tiers of national and international legislation; EU Habitats and Species Directive Annexes II and V, UK Biodiversity Action Plan list of priority species, UK Wildlife and Countryside Act 1981 Schedule 5, Bern Convention Appendix 3, IUCN Red Data List as Critically Endangered. The Afon Eden - Cors Goch Trawsfynydd is the only Special Area of Conservation (SAC) site in Wales where the freshwater pearl mussel Margaritifera margaritifera forms the primary reason for selection of a site. Each year during early summer and when the water temperature is suitable, the female adult mussel releases larvae (glochidia) into the river where they are either ingested or inhaled by host salmonid fish. The species of host fish is specific to each pearl mussel population and prior to these encystment surveys it had been assumed that Atlantic salmon Salmo salar were the host for the Afon Eden population. The results of four annual surveys for gill encystment has proven that brown trout (including sea trout) Salmo trutta is the host species for the Afon Eden population. This dataset contains the results of extent of encystment during electrofishing surveys for salmonid species. The freshwater pearl mussel (Margaritifera margaritifera) is protected under several tiers of national and international legislation; EU Habitats and Species Directive Annexes II and V, UK Biodiversity Action Plan list of priority species, UK Wildlife and Countryside Act 1981 Schedule 5, Bern Convention Appendix 3, IUCN Red Data List as Critically Endangered. The Afon Eden - Cors Goch Trawsfynydd is the only Special Area of Conservation (SAC) site in Wales where the freshwater pearl mussel Margaritifera margaritifera forms the primary reason for selection of a site. Each year during early summer and when the water temperature is suitable, the female adult mussel releases larvae (glochidia) into the river where they are either ingested or inhaled by host salmonid fish. The species of host fish is specific to each pearl mussel population and prior to these encystment surveys it had been assumed that Atlantic salmon Salmo salar were the host for the Afon Eden population. The results of four annual surveys for gill encystment has proven that brown trout (including sea trout) Salmo trutta is the host species for the Afon Eden population. This dataset contains the results of extent of encystment during electrofishing surveys for salmonid species. 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 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 Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme pearl mussels margaritifera margaritifera Afon Eden Atlantic salmon salmo salar brown trout salmo trutta sea trout salmo trutta NRW Thesaurus 2023-12-31 geonetwork.thesaurus.local.theme.converted_nrw-keywords SeaDataNet Parameter Discovery Vocabulary 2021-01-06 geonetwork.thesaurus.external.theme.rdf+xml Integrated Public Sector Vocabulary 2013-04-03 geonetwork.thesaurus.external.theme.subjects NRW SMNR Vocabulary 2023-12-27 geonetwork.thesaurus.local.theme.converted_nrw-smnr-keywords Part of this dataset is sensitive and restricted as it contains data exempt from general release under EIR. Sensitive data must be kept confidential; general release is not permitted due to risk of harm to the environment or third parties. Sensitive details include the location of freshwater pearl mussel. no limitations © CNC/NRW Data may be re-used under provision and in line with the terms of a NRW licence and NRWs guidance on Ecological data exempt from general release. English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 Wales (WLS) -4.09354822 -3.71627339 52.70291324 52.92793706 2013-07-31 2016-07-31 H Garrett (2016) Freshwater pearl mussel larval encystment of host fish species on the Afon Eden – Cors Goch Trawsfynydd SAC . NRW Evidence Report 164. Documents [A] Excel spreadsheet containing data [B] Word documents containing site locations 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 survey methodology consisted of annual electrofishing salmonids on Afon Eden and checking gills for glochidia encystment. Appendix in final summary report gives survey locations and should be kept confidential. Report contributes in EU LIFE Pearls in Peril project. The survey methodology consisted of annual electrofishing salmonids on Afon Eden and checking gills for glochidia encystment. Appendix in final summary report gives survey locations and should be kept confidential. Report contributes in EU LIFE Pearls in Peril project.