A study of the Milford Haven maerl bed in 2005 (paper data)
Maerl beds are a UK Biodiversity Action Plan (BAP) habitat and are also included in the biodiversity duty of public bodies introduced by the NERC Act 2006. Maerl is a collective term for several species of red seaweed, with hard, chalky skeletons. It is rock hard and, unlike other seaweeds, it grows as unattached rounded nodules or short, branched shapes on the seabed. Maerl beds are an important habitat for many different types of marine life, which live amongst or are attached to the surface of Maerl, or burrow in the coarse gravel of dead maerl beneath the top living layer. Maerl beds can be of importance to sustainable fisheries, providing nursery grounds for commercial species of fish and shellfish. In Milford Haven the maerl species Phymatolithon calcareum forms the only living maerl bed in Wales. P. calcareum is listed in the EC Habitats Directive Annex Vb. The aim of this project was to collate high quality images of the Milford Haven maerl bed to create a base line for long term monitoring for Biodiversity Action Plan reporting. There is high confidence in this dataset as the surveyors are amongst the most experienced marine biologists in the UK.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS101780
- Alternative Title
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- 2005 CCW study of the Milford Haven Maerl Bed MRCCW16500000002
- Metadata Language
- English
- Lineage
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The first phase of the fieldwork was to map the extent of the maerl bed in Milford Haven and to determine the distribution and abundance of live maerl using drop down video. The second phase of the fieldwork was detailed study at six sites by divers who recorded the frequency of occurrence of macrobiota in a series of quadrats. At four of the sites, core samples were collected for infaunal and sediment particle size analysis. The present study follows on from work completed in May 2004 (RPS, 2004). RPS carried out an exploratory survey of the maerl bed in Milford Haven waterway in the vicinity of Herbrandston jetty on behalf of South Hook Liquid Natural Gas Terminal Company Ltd (South Hook LNG). This was the most comprehensive work on this maerl bed to date but the survey was partial and significant data gaps remained. The present study was designed to use a similar methodology to that used by RPS and to build on the existing data collected to give a better picture of the extent and quality of the maerl within the Milford Haven waterway.
- Dataset Reference Date (Publication)
- 2007-02-28
Temporal Extent
- Begin date
- 2005-01-01
- End date
- 2005-12-31
- Topic category
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- Biota
Extent
Extent
- Geographic Extent
- Irish Sea
- Geographic Extent
- St. Brides Bay
- Geographic Extent
- SIR BENFRO - PEMBROKESHIRE
- Geographic Extent
- Wales (WLS)
))
Vertical Extent
- Medin Extent Keyword
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benthic boundary layer
Distribution
- Format Type and Description
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Database
(
)
- Specification
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[A] Data is held as video footage [B] Excel spreadsheets [C] Marine Recorder (MRCCW16500000002) [D] Spatial TAB files [E] JPEG images [F] The final report is held in both a Word document and as a .pdf
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Database
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)
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
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This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
- Degree
- false
- Lineage
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The first phase of the fieldwork was to map the extent of the maerl bed in Milford Haven and to determine the distribution and abundance of live maerl using drop down video. The second phase of the fieldwork was detailed study at six sites by divers who recorded the frequency of occurrence of macrobiota in a series of quadrats. At four of the sites, core samples were collected for infaunal and sediment particle size analysis. The present study follows on from work completed in May 2004 (RPS, 2004). RPS carried out an exploratory survey of the maerl bed in Milford Haven waterway in the vicinity of Herbrandston jetty on behalf of South Hook Liquid Natural Gas Terminal Company Ltd (South Hook LNG). This was the most comprehensive work on this maerl bed to date but the survey was partial and significant data gaps remained. The present study was designed to use a similar methodology to that used by RPS and to build on the existing data collected to give a better picture of the extent and quality of the maerl within the Milford Haven waterway.
Keywords
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2008-06-01
Keywords
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NRW Thesaurus
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- Biodiversity Action Plan (BAP)
- underwater conservation
- Maerl beds
- Video survey
- paper data
- underwater photography
- Type
- Theme
Citation
- Date (Publication)
- 2026-08-27
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2024-06-19
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
- NRW Related Title
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A study of the Milford Haven maerl bed in 2005 using drop down video and diving
Constraints
Constraints
Limitations on Public Access and Use
- Restriction type
- Other restrictions
Access Constraints Directive
- Limitations
- no limitations
Access Constraints Text
- Other constraints
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The following data is 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.
Use Constraints
- Use constraints type
- Other restrictions
- Other constraints
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© CNC/NRW and © 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
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313031373830 XML
- Metadata Language
- English
- Parent Identifier
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Natural Resources Wales (NRW) Marine Benthic Species and Habitat Collation Held in Marine Recorder
NRW_DS114501
- Resource type
- Dataset
- Metadata Date
- 2026-09-28T09:18:11.125Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
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1.0