Freshwater pearl mussel (Margaritifera margaritifera) larval encystment of host fish species on the Afon Eden – Cors Goch Trawsfynydd Special Area of Conservation (SAC)

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.

Identification

Identifier
NRW_DS116725
Alternative Title
  • Larfaod codennog Fisglod Perl Dŵr Croyw (Margaritifera margaritifera) rywogaeth bysgodyn lletyol ar yr Afon Eden - Ardal Cadwraeth Arbennig (ACA) Cors Goch Trawsfynydd
Metadata Language
English
Lineage

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.
Additional Information

H Garrett (2016) Freshwater pearl mussel larval encystment of host fish species on the Afon Eden – Cors Goch Trawsfynydd SAC . NRW Evidence Report 164.
Dataset Reference Date (Publication)
2016-07-31
Owner
  Natural Resources Wales (NRW)
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  Natural Resources Wales (NRW)
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 

Extent

Extent

Geographic Extent
Wales (WLS)
N
W
E
S
Map representing the geographic extent of the dataset


 
 

Distribution

Format Type and Description
  • Documents ()

    Specification

    [A] Excel spreadsheet containing data [B] Word documents containing site locations

 

Quality

Data quality

Quality Scope
Dataset
Conformity
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
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

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.
 

Keywords

Keywords

GEMET - INSPIRE themes, version 1.0
Type
Theme

Citation

Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus
  • pearl mussels
  • margaritifera margaritifera
  • Afon Eden
  • Atlantic salmon
  • salmo salar
  • brown trout
  • salmo trutta
  • sea trout
  • salmo trutta
Type
Theme

Citation

Date (Publication)
2023-12-31
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords
 

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Content Information

NRW Profile

Custom Elements

 

Constraints

Constraints

Limitations on Public Access and Use

Restriction type
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

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.
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© 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.
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313136373235 XML
Metadata Language
English
Resource type
Dataset
Metadata Date
2025-03-07T17:31:25.301Z
Metadata Standard Name
NRW
Metadata Standard Version

1.0

pointOfContact
  Natural Resources Wales (NRW)
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

Access the portal