Monitro ACA: Arolygu Wyau Gwangod (Alosa fallax) a Herlynod (Alosa alosa) yn Afon Tywi (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.
- Dull adnabod
- Rhychwant
- Dosbarthiad
- Ansawdd
- Allweddeiriau
- System Cyfeirio Gofodol
- Cynnwys
- Cyfyngiadau
- Cynnal a chadw
- Metadata
Dull adnabod
- Dynodydd
- NRW_DS115312
- Teitl Amgen
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- Shad egg Survey Afon Tywi 2012 - CCW - Report No. 12/8/4 CCW000800000000P
- Laith Metadata
- English
- Datganiad
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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.
- Gwybodaeth ychwanegol
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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.
- Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
- 2013-05-31
Ystod amser
- Dyddiad cychwyn
- 2012-05-22
- Dyddiad gorffen
- 2012-05-29
- Categori pwnc
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- Biota
Rhychwant
Rhychwant
- Hyd
- SIR GAERFYRDDIN - CARMARTHENSHIRE
))
Dosbarthiad
Dosbarthiad
- Fformat - Math a Disgrifiad
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Documents
(
Unknown
)
- Math
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Project report held in Microsoft Word and Adobe PDF formats within Ffynnon (NRW-13-014651; NRW-13-019708).
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Image
(
Unknown
)
- Math
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Survey site photographs held in JPEG format (Document Reference: DCT-12-229420).
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Geographic Information System
(
Unknown
)
- Math
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GIS layers held in MapInfo TAB format, used to produce the associated maps.
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Documents
(
Unknown
)
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
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This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
- Gradd
- false
- Datganiad
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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.
Allweddeiriau
Allweddair
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2008-06-01
Allweddair
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NRW Thesaurus
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- 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
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2026-08-27
System Cyfeirio Gofodol
Cynnwys
Gwybodaeth Cynnwys
Proffil CNC
Elfennau CNC
- Teitlau cysylltiedig CNC
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Afon Tywi SAC shad egg survey 2012
Cyfyngiadau
Cyfyngiadau
Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus
- Math o Gyfyngiad
- Other restrictions
Cyfarwyddeb Cyfyngiadau Mynediad
- Cyfyngiadau
- no limitations
Testun cyfyngiadau mynediad
- Cyfyngiadau eraill
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There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
Defnyddiwch gyfyngiadau
- Cyfyngiadau Defnyddio
- Other restrictions
- Cyfyngiadau eraill
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© 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.
Datganiad Priodoli
- Cyfyngiadau eraill
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Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
Metadata
Metadata
- Dynodydd Ffeil
- 4f4c4942-4343-5764-6473-313135333132 XML
- Laith Metadata
- English
- Dynodydd Rhiant
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Freshwater Shad Monitoring Data
NRW_DS116346
- Math o adnodd
- Dataset
- Dyddiad Metadata
- 2026-09-29T11:13:56.065Z
- Enw Safonol Metadata
- NRW
- Fersiwn Metadata
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1.0