Volunteer Diver Seagrass Zostera marina Surveys, Llyn Peninsula and Milford Haven (2008)

In areas where conditions are suitable seagrass beds form and these are considered nationally important in the UK. Seagrasses are thought to help stabilising the seabed in addition to providing organic matter, shelter and food for a variety of fish, birds and invertebrates. Seagrass beds are vital nursery grounds for flatfish, and in some areas also for cephalopods. They are also known to be sensitive to changes in water quality and human disturbance. Seagrass beds have been designated as a UK Biodiversity Action Plan Habitat (underpinned by the Convention of Biological Diversity, Rio Earth Summit 1992), and as a Habitat of Principal Importance for the Conservation of Biological Diversity in Wales (NERC Act 2006: Section 42). The survey was due to be expanded in 2009 to other areas within the Pen Llyn a'r Sarnau Special Area of Conservation (SAC) and methodologies refined. 1. Develop methods to look at damage to seagrass beds caused by anchor chains compared to permanent moorings. 2. 'Ground-truth' aerial photographs of Porth Dinllaen and Milford Haven subtidal seagrass beds. 3. Test methods of measuring extent of large seagrass beds using volunteers. 4. Estimate density and measure depth of live seagrass in different parts of the bed. 5. Make note of any unusual feature of the seagrass bed.

Identifier: NRW_DS110284

Alternative Title

2008 Seasearch Survey of the Entrances of Milford Haven, Pembrokeshire, Wales MRMCS01200000011
Arolygon gan ddeifars gwirfoddol ar wellt y gamlas Zostera marina, Pen Llyn ac Aberdaugleddau
Seagrass surveys in Porth Dinllaen and the Milford Haven

Metadata Language: English

Lineage: Data is captured by using Volunteer divers who are CMAS 2 star qualified or equivalent with a minimum of 60 dives each. Anchor and density of seagrass shoots are captured by placing quadrats at 5 m intervals along a series of transects that are laid from the centre of the anchor point or seagrass bed. Transects are carried out in a north, south, west and east direction and where time allows also on NE, SW, NW and SE bearings. The number of shoots is counted in each 30 by 30 cm quadrat. In addition the condition of shoot and presence of seeds, black spot disease, snake pipefish and Sargassum muticum (and other non-native species), all of which are believed to be good indicators of the condition of the seagrass bed were recorded. The extent of the beds was also ground-truthed from aerial photographs. Areas (polygons) of suspected seagrass habitats were identified from the photos. An acoustic marker was deployed to the centroid of the polygon, divers were then deployed to the suspected outer edge of the seagrass bed and swam to the acoustic marker using a hand held acoustic homing device. Divers recorded where seagrass started and stopped, changed in seabed types, distance, depth and bearing. The method was repeated until all 8 cardinal points of the compass were complete (time allowing). Methods were tested at Porth Dinllaen as well as measures of extent, density and damaged from anchoring, whereas work in the Milford Haven concentrated on confirming the existence of seagrass beds and their deepest extent. All work carried out contributed to reporting on the features Favourable Conservation Status.

Dataset Reference Date (Publication): 2008-12-31

Temporal Extent

Begin date: 2008-06-14

End date: 2008-09-12

Topic category

Biota

Owner

Natural Resources Wales (NRW)

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

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

Owner

Marine Conservation Society (MCS)

Unit 3,Wolf Business Park,, Alton Road, Ross-on-Wye, Herefordshire, HR9 5NB

http://www.mcsuk.org/

Originator

CCW Marine Monitoring Team

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

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

Originator

Sea-Search Volunteers

Sea-Search c/o Marine Conservation Society, Unit 3 Wolf Business Park, Alton Road, Ross-on-Wye, Herefordshire, HR9 5NB

http://www.seasearch.co.uk

Extent

Geographic Extent: GWYNEDD - GWYNEDD

Geographic Extent: SIR BENFRO - PEMBROKESHIRE

Map representing the geographic extent of the dataset

Vertical Extent

Medin Extent Keyword: benthic boundary layer

Vertical Extent

Minimum value (metres): 1.28

Maximum value (metres): -5.6

Vertical CRS

Format Type and Description

Documents Documents ()

Specification

[A] Transects, density data and anchor data are MapInfo TAB files. [B] Species data held in excel spreadsheets. [C] Seasearch data held in Marine Recorder MRMCS01200000011. [D] Images as JPGs [E] Interim report as word and PDF file.

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: Data is captured by using Volunteer divers who are CMAS 2 star qualified or equivalent with a minimum of 60 dives each. Anchor and density of seagrass shoots are captured by placing quadrats at 5 m intervals along a series of transects that are laid from the centre of the anchor point or seagrass bed. Transects are carried out in a north, south, west and east direction and where time allows also on NE, SW, NW and SE bearings. The number of shoots is counted in each 30 by 30 cm quadrat. In addition the condition of shoot and presence of seeds, black spot disease, snake pipefish and Sargassum muticum (and other non-native species), all of which are believed to be good indicators of the condition of the seagrass bed were recorded. The extent of the beds was also ground-truthed from aerial photographs. Areas (polygons) of suspected seagrass habitats were identified from the photos. An acoustic marker was deployed to the centroid of the polygon, divers were then deployed to the suspected outer edge of the seagrass bed and swam to the acoustic marker using a hand held acoustic homing device. Divers recorded where seagrass started and stopped, changed in seabed types, distance, depth and bearing. The method was repeated until all 8 cardinal points of the compass were complete (time allowing). Methods were tested at Porth Dinllaen as well as measures of extent, density and damaged from anchoring, whereas work in the Milford Haven concentrated on confirming the existence of seagrass beds and their deepest extent. All work carried out contributed to reporting on the features Favourable Conservation Status.

Keywords

GEMET - INSPIRE themes, version 1.0

Species distribution

Type: Theme

Citation

Date (Publication): 2008-06-01

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

Keywords

NRW Thesaurus

zostera marina
eelgrass
Porth Dinllaen
Milford Haven
Pen Llyn a'r Sarnau cSAC
Pembrokeshire Marine SAC
anchor damage

Type: Theme

Citation

Date (Publication): 2023-12-31

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

Keywords

SeaDataNet Parameter Discovery Vocabulary

Macroalgae and seagrass taxonomy-related counts

Type: Theme

Citation

Date (Revision): 2021-01-06

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

Keywords

Integrated Public Sector Vocabulary

volunteers

Type: Theme

Citation

Date (Revision): 2013-04-03

Code: geonetwork.thesaurus.external.theme.subjects

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: This data is jointly owned by NRW and Marine Conservation Society. In addition to this the following data is also considered OS derived data and is therefore jointly owned by NRW and the Ordnance Survey. There are no access restrictions on this data. However there are third party use restrictions. 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 and Marine Conservation Society © Crown copyright. All rights reserved. Natural Resources Wales, AC0000849444 Data may be re-used under provision and in line with the terms of a NRW licence. Those seeking commercial re-use require a commercial licence available from the OS.

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313130323834 XML

Metadata Language: English

Parent Identifier: Across Wales Diving Monitoring Project (2004)
NRW_DS109743

Resource type: Dataset

Metadata Date: 2024-05-31T09:43:40.899Z

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.

Volunteer Diver Seagrass Zostera marina Surveys, Llyn Peninsula and Milford Haven (2008)

Identification

Temporal Extent

Extent

Extent

Vertical Extent

Vertical Extent

Distribution

Quality

Data quality

Keywords

Keywords

Citation

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