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

Monitro ACA: Arolygu Wyau Gwangod (Alosa fallax) a Herlynod (Alosa alosa) yn Afon Wysg (2010-2011)

The River Usk rises in the Black Mountain range in the west of the Brecon Beacons National Park and flows eastwards before turning south to enter the Severn Estuary at Newport. The river is designated as a Special Area of Conservation (SAC) for several features, including salmon, lamprey species, and shad. Twaite shad (Alosa fallax) and allis shad (Alosa alosa) are anadromous members of the family Clupeidae (herring). In Britain, twaite shad are known to spawn in the Rivers Severn, Wye, Usk, and Tywi. However, it remains uncertain whether a breeding population of allis shad still exists.

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 JNCC Common Standards Monitoring Guidance for Freshwater Fauna (2005) sets a target of "no decline in spawning distribution", which is assessed through kick sampling during May and June.

There are two principal sources of data on shad spawning within the River Usk. Environment Agency Wales (EAW), now part of Natural Resources Wales, recorded the presence or absence of shad eggs at a number of sites between 1990 and 2005, although surveys have only been conducted annually since 2003.

Dynodydd Identifier: NRW_DS112727

Teitl Amgen Alternative Title

Shad Egg Survey River Usk 2011 - CCW - Report no.11/8/3 CCW0008000000009
Shad Egg Survey River Usk 2010 - CCW - Report no.10/8/1 CCW000280000000E

Laith Metadata Metadata Language: English

Lineage: The data and associated report describe the monitoring undertaken by former CCW and EAW staff on the spawning distribution of shad during the 2010 and 2011 spawning seasons.

2010: Surveys and evidence of spawning were recorded between 26 May and 22 June.

2011: Surveys and evidence of spawning were recorded between 19 May and 6 July.

Natural Resources Wales also holds records of visible shad spawning at a single location (Usk Town, NGR SO374007) for five consecutive years, from 1997 to 2001.

The standard methodology described by Hillman et al. (2003) was modified to record only the presence or absence of shad eggs. A minimum of 10 kick samples was undertaken at each site, and the number of eggs found in each sample was 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 the dataset is high, as the work was carried out by qualified CCW monitoring staff.

Dyddiad cyfeirnod y set ddata (Cyhoeddiad) Dataset Reference Date (Publication): 2012-01-31

Temporal Extent

Begin date: 2010-05-26

End date: 2011-07-06

Categori pwnc Topic category

Environment

Environment
Biota

Biota
Inland waters

Inland waters

Perchennog

Owner

Natural Resources Wales (NRW) -

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Cychwynnwr

Originator

Countryside Council for Wales (CCW) -

Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW

http://naturalresourceswales.gov.uk/splash?orig=/

Cychwynnwr

Originator

Environment Agency Wales (EA Wales) -

Cambria House, 29 Newport Road, Cardiff, CF24 0TP, Wales

www.environment-agency.gov.uk

Extent

Hyd Geographic Extent: Wales (WLS)

Vertical Extent

Medin Extent Keyword

Dosbarthiad

Distribution

Fformat - Math a Disgrifiad Format Type and Description

Documents ( Unknown )

Specification

Final reports available in Microsoft Word and Adobe PDF formats.
Delimited ( Unknown )

Specification

Raw survey data workbooks held in Microsoft Excel format.
Database ( Unknown )

Specification

Species data are held in Recorder 6 under the following references: CCW000280000000E (2010), CCW0008000000009 (2011)

Ansawdd Data

Data quality

Cwmpas Ansawdd Quality Scope: Dataset

Dataset

Cydymffurfiad 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 data and associated report describe the monitoring undertaken by former CCW and EAW staff on the spawning distribution of shad during the 2010 and 2011 spawning seasons.

2010: Surveys and evidence of spawning were recorded between 26 May and 22 June.

2011: Surveys and evidence of spawning were recorded between 19 May and 6 July.

Natural Resources Wales also holds records of visible shad spawning at a single location (Usk Town, NGR SO374007) for five consecutive years, from 1997 to 2001.

The standard methodology described by Hillman et al. (2003) was modified to record only the presence or absence of shad eggs. A minimum of 10 kick samples was undertaken at each site, and the number of eggs found in each sample was 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 the dataset is high, as the work was carried out by qualified CCW monitoring staff.

Allweddair

Keywords

GEMET - INSPIRE themes, version 1.0

Species distribution

Math Type: Theme

Theme

Dyfyniad

Citation

Dyddiad (Cyhoeddiad) Date (Publication): 2008-06-01

Code: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Allweddair

Keywords

NRW Thesaurus

Countryside Council for Wales (CCW)
clupea harengus
Clupeidae
herring
Eggs
River Usk
Shad
alosa alosa
survey methods (survey techniques) (survey) (surveying)
alosa fallax
Special Areas of Conservation (SAC) (see also Candidate Special Areas of Conservation cSAC)

Math Type: Theme

Theme

Dyfyniad

Citation

Dyddiad (Cyhoeddiad) Date (Publication): 2026-08-27

Code: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Code: British National Grid (EPSG::27700)

Gwybodaeth Cynnwys

Content Information

Proffil CNC

NRW Profile

Elfennau CNC

Custom Elements

NRW Related Title: River Usk shad egg survey 2011

NRW Related Title: River Usk shad egg survey 2010

Constraints

Limitations on Public Access and Use

Math o Gyfyngiad Restriction type: Other restrictions

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

Cyfyngiadau Defnyddio Use constraints type: Other restrictions

Other restrictions

Other constraints: © CNC/NRW 2010 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

Metadata

Dynodydd Ffeil File Identifier: 4f4c4942-4343-5764-6473-313132373237 XML

Laith Metadata Metadata Language: English

Parent Identifier: Condition monitoring of Special Areas of Conservation (SACs) in Wales
NRW_DS110194

Math o adnodd Resource type: Dataset

Dataset

Dyddiad Metadata Metadata Date: 2026-09-29T11:03:41.622Z

Enw Safonol Metadata Metadata Standard Name: NRW

Fersiwn Metadata Metadata Standard Version: 1.0

Pwynt Cyswllt

pointOfContact

Natural Resources Wales (NRW) -

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Publishing Body

Access the portal

Full access to the portal and metadata.

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

Monitro ACA: Arolygu Wyau Gwangod (Alosa fallax) a Herlynod (Alosa alosa) yn Afon Wysg (2010-2011)

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Spatial Reference System

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Gwybodaeth Cynnwys

Content Information

Proffil CNC

NRW Profile

Elfennau CNC

Custom Elements

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Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

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Metadata

Metadata

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Extent

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Dosbarthiad Distribution

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Ansawdd Data Data quality

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Allweddair Keywords

Dyfyniad Citation

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Limitations on Public Access and Use

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Access Constraints Text

Use Constraints

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Metadata

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Dosbarthiad

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Data quality

Allweddair

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Dyfyniad

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Allweddair

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Dyfyniad

Citation

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