SAC Monitoring: Afon Tywi Shad Egg Survey (2012)

The Afon Tywi is designated as a Special Area of Conservation (SAC) 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 former Countryside Council for Wales (CCW), Environment Agency Wales (EAW), and now Natural Resources Wales (NRW) are responsible for monitoring the condition of shad populations within SACs and ensuring the maintenance of favourable conservation status at these designated sites. The Joint Nature Conservation Committee (JNCC) published Common Standards Monitoring Guidance for Freshwater Fauna (JNCC, 2005), which outlines the mandatory and discretionary attributes and targets for monitoring freshwater fish. These include targets relating to shad populations, river flow, water quality, and river morphology.


The purpose of this data collection was to facilitate the assessment of the favourable conservation status of shad within the Afon Tywi. Confidence in this dataset is high, as the surveys were undertaken by experienced staff.

Identification

Identifier
NRW_DS115312
Alternative Title
  • Shad egg Survey Afon Tywi 2012 - CCW - Report No. 12/8/4 CCW000800000000P
Metadata Language
English
Lineage

Countryside Council for Wales (CCW) and Environment Agency Wales (EAW) staff monitored the spawning distribution of shad at 13 sample sites within 60 km of the main river corridor during the 2012 spawning season. The standard methodology was modified to reduce the level of sampling required at sites where shad eggs were present. This enabled the Common Standards Monitoring (CSM) target to be assessed while allowing a greater number of sites to be surveyed within the available time.


The methodology described by Hillman et al. (2003) was adapted so that a minimum of 10 kick samples was undertaken at each site, with the number of eggs recorded for each sample. If 10 or more shad eggs were recorded after 10 kick samples, the survey was terminated. However, if fewer than 10 shad eggs were recorded, kick sampling continued until either 10 eggs had been found or a maximum of 25 kick samples had been completed.
Additional Information

Garrett, H.M., Thomas, Rh. & Hatton-Ellis, T.W. (2012). Afon Tywi SAC shad egg survey 2012. CCW Staff Science Report No. 12/8/4. 37pp, CCW. Bangor.
Dataset Reference Date (Publication)
2013-05-31

Temporal Extent

Begin date
2012-05-22
End date
2012-05-29
 
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
SIR GAERFYRDDIN - CARMARTHENSHIRE
N
W
E
S
Map representing the geographic extent of the dataset


 
 

Distribution

Distribution

Format Type and Description
  • Documents ( Unknown )

    Specification

    Project report held in Microsoft Word and Adobe PDF formats within Ffynnon (NRW-13-014651; NRW-13-019708).

  • Image ( Unknown )

    Specification

    Survey site photographs held in JPEG format (Document Reference: DCT-12-229420).

  • Geographic Information System ( Unknown )

    Specification

    GIS layers held in MapInfo TAB format, used to produce the associated maps.

 

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

Countryside Council for Wales (CCW) and Environment Agency Wales (EAW) staff monitored the spawning distribution of shad at 13 sample sites within 60 km of the main river corridor during the 2012 spawning season. The standard methodology was modified to reduce the level of sampling required at sites where shad eggs were present. This enabled the Common Standards Monitoring (CSM) target to be assessed while allowing a greater number of sites to be surveyed within the available time.


The methodology described by Hillman et al. (2003) was adapted so that a minimum of 10 kick samples was undertaken at each site, with the number of eggs recorded for each sample. If 10 or more shad eggs were recorded after 10 kick samples, the survey was terminated. However, if fewer than 10 shad eggs were recorded, kick sampling continued until either 10 eggs had been found or a maximum of 25 kick samples had been completed.
 

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
  • alosa alosa
  • allis shad
  • Special Area of Conservation Monitoring
  • Special Areas of Conservation (SAC) - SAC monitoring
  • twaite shad
  • river Tywi (afon Tywi)
  • Shad
  • alosa fallax
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

NRW Related Title

Afon Tywi SAC shad egg survey 2012
 

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 to this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© CNC/NRW 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 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
4f4c4942-4343-5764-6473-313135333132 XML
Metadata Language
English
Parent Identifier
Freshwater Shad Monitoring Data

NRW_DS116346
Resource type
Dataset
Metadata Date
2026-09-29T11:13:56.065Z
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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