Llyn Tegid and Llyn Arenig Fawr hydroacoustic and Gwyniad surveys 2012

The gwyniad (Coregonus lavaretus) population of Llyn Tegid has, for a number of years, been considered threatened by deteriorating environmental conditions, particularly those associated with eutrophication.


This dataset contains the results of a project investigating the environmental factors affecting the species and its habitat. Attempts have been made since 2003 to establish a refuge population through the translocation of gwyniad to Llyn Arenig Fawr.


The purpose of this study was to assess the status of gwyniad and its habitat in both Llyn Tegid, which supports the native population, and Llyn Arenig Fawr, which supports the introduced population.

Identification

Identifier
NRW_DS115217
Alternative Title
  • Gwyniad Hydroacoustic and Gill Netting Survey of Llyn Arenig Fawr 2012- CCW Science Report 1013 CCW000800000000I
  • Gwyniad Hydroaccoustic Survey of Llyn Tegid 2012 - CCW Science Report 1012 CCW000800000000G
Metadata Language
English
Lineage

At Llyn Tegid, hydroacoustic surveys were conducted alongside measurements of associated environmental variables, including temperature and oxygen profiles, and Secchi disc readings.


The survey utilised the standardised protocol for the assessment and monitoring of whitefish populations (Bean, 2003; JNCC, 2005), with two minor deviations. Firstly, the fish length-target strength relationship described by Love (1971) was used instead of that proposed by Foote (1987) to facilitate wider comparison with other studies. Secondly, a vessel speed of 2.0 m s⁻¹ was adopted as the target mean speed rather than as an absolute upper limit.


Equivalent data collection was also undertaken at Llyn Arenig Fawr, including a standardised gill-net survey.


This dataset forms part of the continuation of the Llyn Tegid Hydroacoustic Surveys and Gwyniad Translocations 2004-2009 project.
Additional Information

Ffynnon Reference Number: DCT-13-068971 / DCT-13-068914: Llyn Tegid Hydroacoustic Survey 2012 I. Winfield., J. Fletcher., and J. James., CCW Contract Science Report No. 1012


Ffynnon Reference Number: DCT-13-068851 / DCT-13-069046: Llyn Arenig Fawr Gwyniad Survey 2012 Winfield., J. Fletcher., and J. James., CCW Contract Science Report No. 1013
Dataset Reference Date (Publication)
2012-08-07

Temporal Extent

Begin date
2012-08-06
End date
2012-08-07
 
Topic category
  • Biota
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  Centre for Ecology and Hydrology (CEH) -
Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, Wales
http://www.ceh.ac.uk/
 

Extent

Extent

Geographic Extent
GWYNEDD - GWYNEDD
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword

water column
 
 

Distribution

Distribution

Format Type and Description
  • Binary ( Unknown )

    Specification

    Oxygen and temperature profiles in Excel (.xls) format; Raw echo sounder acquisition data (.dt4); Species data in Excel (.xls) format

  • Database ( Unknown )

    Specification

    Recorder 6 species datasets

  • Delimited ( Unknown )

    Specification

    Echoview laboratory analysis data in CSV format

  • Image ( Unknown )

    Specification

    JPEG images

  • Documents ( Unknown )

    Specification

    Final reports in Microsoft Word and Adobe PDF formats

 

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

At Llyn Tegid, hydroacoustic surveys were conducted alongside measurements of associated environmental variables, including temperature and oxygen profiles, and Secchi disc readings.


The survey utilised the standardised protocol for the assessment and monitoring of whitefish populations (Bean, 2003; JNCC, 2005), with two minor deviations. Firstly, the fish length-target strength relationship described by Love (1971) was used instead of that proposed by Foote (1987) to facilitate wider comparison with other studies. Secondly, a vessel speed of 2.0 m s⁻¹ was adopted as the target mean speed rather than as an absolute upper limit.


Equivalent data collection was also undertaken at Llyn Arenig Fawr, including a standardised gill-net survey.


This dataset forms part of the continuation of the Llyn Tegid Hydroacoustic Surveys and Gwyniad Translocations 2004-2009 project.
 

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
  • gwyniad (freshwater whitefish)
  • coregonus lavaretus
  • hydroacoustic
  • Llyn Tegid
  • secchi depth
  • Llyn Arenig Fawr
  • oxygen profile
  • marine and freshwater inventory
  • temperature profile
Type
Theme

Citation

Date (Publication)
2026-08-27
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Keywords

SeaDataNet Parameter Discovery Vocabulary
Type
Theme

Citation

Date (Publication)
2024-06-19
Code
geonetwork.thesaurus.external.theme.rdf+xml
 

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Content Information

NRW Profile

Custom Elements

NRW Related Title

Llyn Arenig Fawr Gwyniad survey 2009
NRW Related Title

Llyn Tegid hydroacoustic 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 2012. 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.
 

Licence

Other constraints
Open Government Licence
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313135323137 XML
Metadata Language
English
Parent Identifier
Freshwater Gwyniad (Coregonus lavaretus) Species Survey Data

NRW_DS116344
Resource type
Dataset
Metadata Date
2026-10-01T14:09:35.124Z
Metadata Standard Name
NRW
Metadata Standard Version

1.0

pointOfContact
  Master Reference Data Team -
Natural Resources Wales, Maes y Fynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW
http://naturalresourceswales.gov.uk/splash?orig=/
 
 

Publishing Body

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