Acoustic Monitoring of South Llyn (East of the Tudwels) and Subsequent Infauna Sampling

A side-scan sonar survey was carried out in Tremadog Bay following reports of possible scallop dredging within the Sea Fisheries Scallop Exclusion Zone. The acoustic survey was followed up by infaunal sampling to look at the effect of disturbance of the substrata within the area. The purpose of this data capture was to investigate reports of possible scallop dredging within the Exclusion Zone and its effects on biodiversity within the Special Area of Conservation (SAC) and Exclusion Zone. Confidence in this dataset is high. The side-scan data is processed to reduce errors (e.g. positional corrections).

Identifier: NRW_DS110872

Alternative Title

Gwaith monitro acwstig yn Ne Llyn (i'r dwyrain o Ynys Tudwal) a gwaith dilynol ar samplo'r isfilod
Side-scan survey of South Llyn

Metadata Language: English

Lineage: Side scan-sonar data was captured from Countryside Council for Wales' (CCW) research vessel (R.V. Pedryn) using a CMAX CM800 side-scan sonar. Two areas were selected for infaunal sampling. A control site (with no dredge activity) and one area where there was evidence of recent dredge activity. Infaunal sampling was carried by divers using a 0.1 m2 quadrat. 5 Quadrats were randomly placed in the belly of a dredge scar and 5 within the control site. Surface material was collected by hand and a diver operated suction sampler was used to remove the sediment within the quadrat to a depth of 20cms using a 0.5mm filter mesh bag. Large cobbles within the sediment too big for sampler were removed by hand and placed in a large 0.5mm mesh sample bag along with the plastic bag containing surface cobbles and the suction sampler filter bag. A sediment sample was collected by the diver adjacent to the quadrat using a 1/2litre sealed plastic bucket for granulometry. The contents of the suction sample filter bag and cobbles from within the sediment were transferred to sample buckets on the surface and fixed in 20% formalin diluted with seawater. In addition one 2x2 m quadrat was photographed in 40 cm blocks at both the control site and within one dredge scar. Photos will be stitched together to create a photographic mosaic of the quadrat.

Dataset Reference Date (Publication): 2009-08-31

Temporal Extent

Begin date: 2009-06-09

End date: 2009-08-31

Topic category

Environment
Biota

Owner

Natural Resources Wales (NRW)

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

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

Originator

CCW Marine Monitoring Team

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

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

Extent

Geographic Extent: Irish Sea

Geographic Extent: GWYNEDD - GWYNEDD

Map representing the geographic extent of the dataset

Vertical Extent

Medin Extent Keyword: benthic boundary layer

Vertical Extent

Minimum value (metres): 0

Maximum value (metres): -12

Vertical CRS

Format Type and Description

Documents Documents ()

Specification

[A] Side-scan data mosaiced raster TIFF images [B] Video data as avi files [C] Dredge position and sample metadata in MapInfo TAB files [D] Images as JPGs and NEF raw files

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
Degree: false

Lineage: Side scan-sonar data was captured from Countryside Council for Wales' (CCW) research vessel (R.V. Pedryn) using a CMAX CM800 side-scan sonar. Two areas were selected for infaunal sampling. A control site (with no dredge activity) and one area where there was evidence of recent dredge activity. Infaunal sampling was carried by divers using a 0.1 m2 quadrat. 5 Quadrats were randomly placed in the belly of a dredge scar and 5 within the control site. Surface material was collected by hand and a diver operated suction sampler was used to remove the sediment within the quadrat to a depth of 20cms using a 0.5mm filter mesh bag. Large cobbles within the sediment too big for sampler were removed by hand and placed in a large 0.5mm mesh sample bag along with the plastic bag containing surface cobbles and the suction sampler filter bag. A sediment sample was collected by the diver adjacent to the quadrat using a 1/2litre sealed plastic bucket for granulometry. The contents of the suction sample filter bag and cobbles from within the sediment were transferred to sample buckets on the surface and fixed in 20% formalin diluted with seawater. In addition one 2x2 m quadrat was photographed in 40 cm blocks at both the control site and within one dredge scar. Photos will be stitched together to create a photographic mosaic of the quadrat.

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

sediment epifauna
sediment infauna
sediment sample
sediments
benthic communities
benthic environment
Infauna
Tremadog Bay
dredging
sidescan sonar
acoustic observation (acoustic monitoring)
acoustic remote sensing
surveillance

Type: Theme

Citation

Date (Publication): 2023-12-31

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

Keywords

SeaDataNet Parameter Discovery Vocabulary

Zoobenthos generic abundance
Zoobenthos taxonomic abundance
Zoobenthos taxonomy-related counts

Type: Theme

Citation

Date (Revision): 2021-01-06

Code: geonetwork.thesaurus.external.theme.rdf+xml

Code: Latitude and Longitude (EPSG::4326)

Content Information

NRW Profile

Custom Elements

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 2009 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. All intellectual property rights (including copyright and database rights) are owned by CCW, except video footage taken by Paul Kay. Applicants seeking to re-use this material should approach Paul Kay directly to obtain permission.

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313130383732 XML

Metadata Language: English

Resource type: Dataset

Metadata Date: 2024-05-31T09:37:36.657Z

Metadata Standard Name: NRW

Metadata Standard Version: 1.0

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.

Acoustic Monitoring of South Llyn (East of the Tudwels) and Subsequent Infauna Sampling

Identification

Temporal Extent

Extent

Extent

Vertical Extent

Vertical Extent

Distribution

Quality

Data quality

Keywords

Keywords

Citation

Keywords

Citation

Keywords

Citation

Spatial Reference System

Content

Content Information

NRW Profile

Custom Elements

Constraints

Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

Use Constraints

Metadata

Metadata

Publishing Body