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Metadata: Monitoring of Carbonate Reef Extent and Fish Population at Holden's Reef (2003 - 2010)
Abstract:
Holden's Reef is a small (approximately 40 m diameter), roughly circular reef situated in the northern sector of Cardigan Bay. It is unusual in being formed as a result of a chemical reaction between seawater and the escape of natural gas from the seabed, a phenomenon generally found in much deeper waters. Holden's Reef is one of an assemblage of methanogen-precipitated calcium carbonate reefs and was the first of the group to be discovered. This dataset contains the results of a programme of monitoring established to study fish populations and reef extent. It also includes data from an in-house survey carried out at Holden's Reef in 2003, initiated following the reef's discovery, and Marine Nature Conservation Review (MNCR) phase 2 surveys carried out in 2005 of \Little\" and \"Big\" Reef. Holden's Reef is monitored for fish abundance and diversity extent and rugosity (the link between rugosity and fish abundance has been seen in several studies). This will contribute to condition assessment of the reef feature in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). Holden's Reef is situated more than 10 km off shore north west of Barmouth and is approximately 40 m in diameter. "
Data holder:
Natural Resources Wales (NRW)
Click on the red button for resource contact details:
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| Other details | ||
| Internal code | Internally assigned metadata identifier | 8684 |
| Title | The title is used to provide a brief and precise description of the dataset such as 'Date', 'Originating organisation/programme', 'Location' and 'Type of survey'. All acronyms and abbreviations should be reproduced in full. | Monitoring of Carbonate Reef Extent and Fish Population at Holden's Reef (2003 - 2010) |
| Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | 2003 CCW Holden's Reef initial survey MRCCW30000000030, 2005 CCW/Pelagial/Sea-Scope Holden's Reef, Pen Llyn a'r Sarnau sublittoral survey MRCCW3010000000D, Carbonate reef extent and rugosity, Holden's Reef, Fish abundance and diversity at Holden's Reef |
| File Identifier | The File Identifier is a code, preferably a GUID, that is globally unique and remains with the same metadata record even if the record is edited or transferred between portals or tools. | NRW_DS110926 |
| Resource Identifier | This is the code assigned by the data owner. | 4f4c4942-4343-5764-6473-313130393236 |
| Resource type | The resource type will likely be a dataset but could also be a series (collection of datasets with a common specification) or a service. | dataset |
| Start date | This describes the date the resource starts. This may only be the year if month and day are not known | 2004-05-18 |
| End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2010-12-31 |
| Frequency of updates | This describes the frequency with which the resource is modified or updated i.e. a monitoring programme that samples once per year has a frequency that is described as 'annually'. | annually |
| Abstract | The abstract provides a clear and brief statement of the content of the resource. | Holden's Reef is a small (approximately 40 m diameter), roughly circular reef situated in the northern sector of Cardigan Bay. It is unusual in being formed as a result of a chemical reaction between seawater and the escape of natural gas from the seabed, a phenomenon generally found in much deeper waters. Holden's Reef is one of an assemblage of methanogen-precipitated calcium carbonate reefs and was the first of the group to be discovered. This dataset contains the results of a programme of monitoring established to study fish populations and reef extent. It also includes data from an in-house survey carried out at Holden's Reef in 2003, initiated following the reef's discovery, and Marine Nature Conservation Review (MNCR) phase 2 surveys carried out in 2005 of \Little\" and \"Big\" Reef. Holden's Reef is monitored for fish abundance and diversity extent and rugosity (the link between rugosity and fish abundance has been seen in several studies). This will contribute to condition assessment of the reef feature in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC). Holden's Reef is situated more than 10 km off shore north west of Barmouth and is approximately 40 m in diameter. " |
| Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | A site marker (a single road pin) has been established at the centre of the reef in its shallowest part. An additional marker is located due north from the centre at the edge of the reef. The extent of the reef is measured by divers who swim along a bearing from the central marker to the edge of the reef and the distance recorded. The distance from the centre to the edge of the reef is measured at 12 bearings 30 degrees apart. The rugosity of the reef is measured by splitting the reef into an inner and outer zone radiating from the central marker. The distance between the centre and zone boundary is measured using a taut tape measure. This distance is then repeated allowing the tape measure to rest along the contours if the reef. The rugosity is determined to be the ratio between the two measurements. Fish abundance and diversity is measured by a pair of divers undertaking 3 consecutive timed counts of 5 minute duration. These counts take place in up to 4 zones that represent different topography and depths on the reef. To aid recording slates are pre-marked with species likely to be observed. |
| Additional information | This describes relevant references to the data e.g. reports, articles, websites plus other useful information not captured elsewhere. | Detailed methodologies in use at Holden's Reef can be found in Marine Monitoring Report 25b (standard operating procedures 11 12 and 13) |
| Related keywords | ||
| Keyword | General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitats and biotopes |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Species distribution | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | carbonate reef | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | methane | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Holden's Reef | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Special Area of Conservation Monitoring | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | fish ecology | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | marine monitoring (see also marine surveys) | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Pen Llyn a'r Sarnau cSAC | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish abundance in water bodies | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitat characterisation | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Habitat extent | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish taxonomy-related counts | |
| Geographical coverage | ||
| North | The northern-most limit of the data resource in decimal degrees | 52.741304 |
| East | The eastern-most limit of the data resource in decimal degrees | -4.129506 |
| South | The southern-most limit of the data resource in decimal degrees | 52.735966 |
| West | The western-most limit of the data resource in decimal degrees | -4.140899 |
| Regional sea | Irish Sea | |
| Cardigan Bay | ||
| Tremadog Bay | ||
| GWYNEDD - GWYNEDD | ||
| Responsible organisations | ||
| Role | The point of contact is person or organisation with responsibility for the creation and maintenance of the metadata for the resource. | pointOfContact |
| Organisation name | Natural Resources Wales (NRW) | |
| Delivery point | Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresources.wales/?lang=en | |
| Role | The owner is the person or organisation that owns the resource. | owner |
| Organisation name | Natural Resources Wales (NRW) | |
| Delivery point | Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresources.wales/?lang=en | |
| Role | The custodian is the person or organisation that accepts responsibility for the resource and ensures appropriate care and maintenance. If a dataset has been lodged with a Data Archive Centre for maintenance then this organisation is be entered here. | custodian |
| Organisation name | Natural Resources Wales (NRW) | |
| Delivery point | Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresources.wales/?lang=en | |
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | Various contractors | |
| Delivery point | See Natural Resources Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresourceswales.gov.uk/splash?orig=/ | |
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | CCW Marine Monitoring Team | |
| Delivery point | Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresourceswales.gov.uk/splash?orig=/ | |
| Role | The distributor is the person or organisation that distributes the resource. | distributor |
| Organisation name | Natural Resources Wales (NRW) | |
| Delivery point | Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales | |
| enquiries@naturalresourceswales.gov.uk | ||
| URL | http://naturalresources.wales/?lang=en | |
| Dataset constraints | ||
| 20.1 Limitations on Public Access - Access constraints | This states `otherRestrictions` from ISO vocabulary RestrictionCode and is an INSPIRE/GEMINI requirement. | otherRestrictions |
| 20.2 Limitations on Public Access - Other constraints | This states any limitations on access to the data. Multiple occurences are allowed here. One entry shall be from the INSPIRE Metadata registry and the other free text should be part of the resource `Have specific limitations`. | There are no access restrictions to this data. NRW may release, publish or disseminate it freely. |
| no limitations | ||
| 21.1 Conditions for Access and Use - Use constraints | This states `otherRestrictions` from ISO vocabulary RestrictionCode and is an INSPIRE/GEMINI requirement. | otherRestrictions |
| 21.2 Conditions for Access and Use - Other constraints | This states any constraints on use of the data. Multiple conditions can be recorded for different parts of the data resource. If no conditions apply, then `No condtions apply` is recorded. This uses free text. | © CNC/NRW 2010. 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. |
| Available data formats | ||
| Data format | Format in which digital data can be provided for transfer | Database |
| Version info | ||
| Date of publication | The publication date of the resource or if previously unpublished the date that the resource was made publicly available via the MEDIN network. | 2010-12-31 |
| Harvest date | The date which this record has been (re)harvested from the provider. | 2026-04-19 |
| Metadata date | The date when the content of this metadata record was last updated. | 2026-03-03 |
| Metadata standard name | The name of the metadata standard used to create this metadata | MEDIN |
| Metadata standard version | The version of the MEDIN Discovery Metadata Standard used to create the metadata record | 3.1.2 |
| Metadata parent | NRW_DS114501 | |