Tremadog Bay Subtidal Macrobenthic Study
Astudiaeth Facrofenthig Islanwol Bae Tremadog

  • English
  • wel
  • All

The Habitats Directive establishes that the management of Special Area of Conservation (SACs) should aim to achieve the 'Favourable Conservation Status' (FCS) of habitats and species as defined in the Directive. In the case of SACs, the features to which FCS applies are the habitats and/or species listed in Annex I and Annex II of the Habitat Directive for which the individual site has been selected. Infaunal monitoring work is required to provide management feedback and enable reporting on the FCS of infaunal aspects of SACs, Special Protection Areas (SPAs: Birds Directive) and Special Sites of Scientific Interest (SSSI).


The aim of this data capture was to gather repeatable data to provide reference conditions and to support the identification of the two characteristics of the Pen Llyn a'r Sarnau large shallow inlet and bays feature. Tremadog Bay a large shallow Inlet and Bay within the Pen Llyn a'r Sarnau SAC. Two important characteristics of this feature have been identified. These are:

1. The variety of subtidal sediment communities within the large shallow inlet and bay

2. The species richness and diversity of the sublittoral mixed sediment south west of Pwllheli

Identification

Dynodydd
Identifier
NRW_DS109835
Teitl Amgen
Alternative Title
  • 2004 CCW Tremadog Bay sublittoral sediment survey MRCCW3010000000F
  • 2005 CCW Tremadog Bay sublittoral sediment survey MRCCW3010000000E
Laith Metadata
Metadata Language
English
Lineage

A total of 115 samples were obtained at 39 sites within Tremadog Bay over a 2 year period. Analysis of samples produced a list of all benthic fauna (infauna and epifauna). In addition sediment composition was described. Biotopes were also assigned to each sample based on the classification of Connor et al, 2004. The sample stations were designed on a grid system, with additional stations created on known mixed sediment areas and additional areas or particular interest. Grab samples were collected with a 0.1m2 day grab. 2 or more samples were collected at each station, with 6 replicates taken in mixed sediment areas.


A granulometry sample was taken from one of the grabs. Grab samples are sieved on board the survey vessel, through a 0.5mm mesh sieve, Samples with a large amount of coarse material were put through a 1mm mesh sieve first to speed up the process. The sieved material was then fixed on 10% formalin solution. Macrofaunal and particle size distribution analysis of the grab samples was completed under contract to EMU Ltd. Following the macrobenthic analysis, biotopes were assigned to each sampling station.
Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
Dataset Reference Date (Publication)
2008-04-30
Perchennog
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Cychwynnwr
Originator
  Various -
Enquiries Unit, Maes y Fynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW
http://naturalresourceswales.gov.uk/splash?orig=/
 

Extent

Extent

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


 

Vertical Extent

Medin Extent Keyword
benthic boundary layer

Maint Fertigol
Vertical Extent

Gwerth lleiaf
Minimum value (metres)
-4.3
Gwerth uchaf
Maximum value (metres)
-29.47
System Gyfeirio Cydlynu Fertigol
Vertical CRS
 
 

Distribution

Dosbarthiad
Distribution

Fformat - Math a Disgrifiad
Format Type and Description
  • Documents ( )

    Specification

    The report is held as a .pdf and Word document.

  • Database ( )

    Specification

    Infaunal core species matrices and sediment analysis held in excel documents. [D] Species, habitat and PSA data also held in Marine Recorder (MRCCW3010000000E, MRCCW3010000000F)

  • Image ( )

    Specification

    Figures are held as both .pdf and JPEG's

  • Delimited ( )

    Specification

    Survey logs held in excel.

 

Quality

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

A total of 115 samples were obtained at 39 sites within Tremadog Bay over a 2 year period. Analysis of samples produced a list of all benthic fauna (infauna and epifauna). In addition sediment composition was described. Biotopes were also assigned to each sample based on the classification of Connor et al, 2004. The sample stations were designed on a grid system, with additional stations created on known mixed sediment areas and additional areas or particular interest. Grab samples were collected with a 0.1m2 day grab. 2 or more samples were collected at each station, with 6 replicates taken in mixed sediment areas.


A granulometry sample was taken from one of the grabs. Grab samples are sieved on board the survey vessel, through a 0.5mm mesh sieve, Samples with a large amount of coarse material were put through a 1mm mesh sieve first to speed up the process. The sieved material was then fixed on 10% formalin solution. Macrofaunal and particle size distribution analysis of the grab samples was completed under contract to EMU Ltd. Following the macrobenthic analysis, biotopes were assigned to each sampling station.
 

Keywords

Allweddair
Keywords

GEMET - INSPIRE themes, version 1.0
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Allweddair
Keywords

NRW Thesaurus
  • large shallow inlet and bay
  • sediment infauna
  • Pen Llyn a'r Sarnau cSAC
  • Tremadog Bay
  • sediment epifauna
  • marine sediments (coastal sediments) (intertidal sediments) (subtidal sediments)
  • macrobenthos
  • Special Area of Conservation Monitoring
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2025-01-08
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords

Allweddair
Keywords

SeaDataNet Parameter Discovery Vocabulary
Math
Type
Theme
Theme

Dyfyniad
Citation

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

Spatial Reference System

Code
Latitude and Longitude (EPSG::4326)
 

Content

Gwybodaeth Cynnwys
Content Information

Proffil CNC
NRW Profile

Elfennau CNC
Custom Elements

NRW Related Title

Tremadog Bay subtidal macrobenthic study
 

Constraints

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 on 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 Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and copyright of the owners. It is the recipient's responsibility to ensure the data is fit for the intended purpose.
 

Attribution Statement

Other constraints

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
 
 
 

Metadata

Metadata

Dynodydd Ffeil
File Identifier
4f4c4942-4343-5764-6473-313039383335 XML
Laith Metadata
Metadata Language
English
Parent Identifier
Natural Resources Wales (NRW) Marine Benthic Species and Habitat Collation Held in Marine Recorder

NRW_DS114501
Math o adnodd
Resource type
Dataset
Dataset
Dyddiad Metadata
Metadata Date
2026-03-03T14:43:50.957Z
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

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