Data Monitro Gwangen Dŵr Croyw
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.
- Dull adnabod
- Rhychwant
- Dosbarthiad
- Ansawdd
- Allweddeiriau
- System Cyfeirio Gofodol
- Cynnwys
- Cyfyngiadau
- Cynnal a chadw
- Metadata
Dull adnabod
- Dynodydd
- NRW_DS116346
- Teitl Amgen
-
- Laith Metadata
- English
- Datganiad
-
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.
- Gwybodaeth ychwanegol
-
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).
- Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
- 2016-08-17
Ystod amser
- Dyddiad cychwyn
- 1980-01-01
- Dyddiad gorffen
- 2012-12-31
- Categori pwnc
-
- Biota
Rhychwant
Rhychwant
- Hyd
- Wales (WLS)
))
Maint Fertigol
- Maint allweddair MEDIN
Dosbarthiad
Dosbarthiad
- Fformat - Math a Disgrifiad
-
-
Database
(
Unknown
)
- Math
-
Species data are held in Recorder 6.
-
Text or Plaintext
(
Unknown
)
- Math
-
This dataset is available for download through the NBN Gateway (see Resource Locator).
-
Database
(
Unknown
)
- Lleolwr Adnoddau
- View and Download Data ( WWW:LINK-1.0-http--link )
Ansawdd
Ansawdd Data
- Cwmpas Ansawdd
- Dataset
- Cydymffurfiad
- 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
- Eglurhad
-
This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
- Gradd
- false
- Datganiad
-
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.
Allweddeiriau
Allweddair
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2008-06-01
Allweddair
-
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]
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2026-08-27
System Cyfeirio Gofodol
Cynnwys
Gwybodaeth Cynnwys
Proffil CNC
Elfennau CNC
Cyfyngiadau
Cyfyngiadau
Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus
- Math o Gyfyngiad
- Other restrictions
Cyfarwyddeb Cyfyngiadau Mynediad
- Cyfyngiadau
- no limitations
Testun cyfyngiadau mynediad
- Cyfyngiadau eraill
-
There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Defnyddiwch gyfyngiadau
- Cyfyngiadau Defnyddio
- Other restrictions
- Cyfyngiadau eraill
-
© 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.
Datganiad Priodoli
- Cyfyngiadau eraill
-
Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
Metadata
Metadata
- Dynodydd Ffeil
- 4f4c4942-4343-5764-6473-313136333436 XML
- Laith Metadata
- English
- Dynodydd Rhiant
-
Natural Resources Wales (NRW) Species Data on the NBN Atlas
NRW_DS116805
- Math o adnodd
- Dataset
- Dyddiad Metadata
- 2026-09-29T10:57:56.384Z
- Enw Safonol Metadata
- NRW
- Fersiwn Metadata
-
1.0