Freshwater Shad Monitoring Data

The Rivers Wye, Usk, and Tywi are designated as Special Areas of Conservation (SACs) under the EC Habitats Directive (92/43/EEC) for several qualifying features, including twaite shad (Alosa fallax) and allis shad (Alosa alosa). Shad are migratory members of the Clupeidae (herring) family that ascend rivers to spawn in late spring. Populations of both species are threatened across Europe, primarily due to barriers to migration and issues relating to water quality.


In the UK, significant populations of shad spawn in the Rivers Severn, Usk, Wye, and Tywi. The Rivers Wye, Usk, and Tywi have been designated as SACs for shad and other features, including salmon, lamprey species, and bullhead. However, it remains uncertain whether a breeding population of allis shad still exists within these rivers.


The former Countryside Council for Wales (CCW), now Natural Resources Wales (NRW), is responsible for monitoring the condition of shad populations within SACs and ensuring the maintenance of favourable conservation status at these designated sites. The purpose of this data capture was to support the assessment of favourable conservation status within the Wye, Usk, and Tywi catchments and to supplement the primary shad spawning distribution condition assessments undertaken for these rivers.


This dataset comprises a number of surveys recorded in Recorder 6 that have been packaged for dissemination through the NBN Atlas. Detailed information relating to each survey can be found within the corresponding individual metadata records.

Identification

Identifier
NRW_DS116346
Alternative Title
Metadata Language
English
Lineage

Environment Agency Wales (EAW) and the Countryside Council for Wales (CCW) recorded shad egg survey data for the Rivers Wye, Usk, and Tywi. A minimum of 10 kick samples was undertaken at each site, with the number of eggs found in each sample recorded. If a total of 10 shad eggs was recorded, the survey was terminated. However, if fewer than 10 shad eggs were recorded, kick sampling continued until either more than 10 eggs had been found or a maximum of 25 kick samples had been undertaken. Confidence in this dataset is high.
Additional Information

For further information see the survey metadata:

NRW_DS107792 SAC Monitoring: Shad Monitoring data for Rivers Wye, Usk and Tywi (2006).

NRW_DS112727 SAC Monitoring: Twaite (Alosa fallax) and Allis (Alosa alosa) Shad egg survey of the River Usk (2010-2011).

NRW_DS114673 SAC Monitoring: Shad Egg Survey on the River Wye (2011).

NRW_DS115312 SAC Monitoring: Afon Tywi Shad Egg Survey (2012).

NRW_DS115294 SAC Monitoring: Shad Egg Survey River Usk and River Wye (2012).
Dataset Reference Date (Publication)
2016-08-17

Temporal Extent

Begin date
1980-01-01
End date
2012-12-31
 
Topic category
  • Biota
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  Countryside Council for Wales (CCW) -
Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW
http://naturalresourceswales.gov.uk/splash?orig=/
Originator
  Environment Agency Wales (EA Wales) -
Cambria House, 29 Newport Road, Cardiff, CF24 0TP, Wales
www.environment-agency.gov.uk
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


 

Vertical Extent

Medin Extent Keyword
 
 

Distribution

Distribution

Format Type and Description
  • Database ( Unknown )

    Specification

    Species data are held in Recorder 6.

  • Text or Plaintext ( Unknown )

    Specification

    This dataset is available for download through the NBN Gateway (see Resource Locator).

Resource Locator
View and Download Data ( WWW:LINK-1.0-http--link )
 

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

Environment Agency Wales (EAW) and the Countryside Council for Wales (CCW) recorded shad egg survey data for the Rivers Wye, Usk, and Tywi. A minimum of 10 kick samples was undertaken at each site, with the number of eggs found in each sample recorded. If a total of 10 shad eggs was recorded, the survey was terminated. However, if fewer than 10 shad eggs were recorded, kick sampling continued until either more than 10 eggs had been found or a maximum of 25 kick samples had been undertaken. Confidence in this dataset is high.
 

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
  • twaite shad
  • allis shad
  • River Usk
  • Shad
  • Special Areas of Conservation (SAC) - SAC monitoring
  • Special Areas of Conservation (SAC) (see also Candidate Special Areas of Conservation cSAC)
  • NBN Atlas
  • alosa alosa
  • alosa fallax
  • National Biodiversity Network [NBN]
Type
Theme

Citation

Date (Publication)
2026-08-27
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

There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© CNC/NRW 2011 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.
 

Attribution Statement

Other constraints

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313136333436 XML
Metadata Language
English
Parent Identifier
Natural Resources Wales (NRW) Species Data on the NBN Atlas

NRW_DS116805
Resource type
Dataset
Metadata Date
2026-09-29T10:57:56.384Z
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

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