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Didemnum vexillum is an invasive colonial ascidian that has become established world-wide having been identified in Japan, North America, northern Europe, and New Zealand, following a global expansion since the 1970’s. It forms sheet like colonies on natural and artificial hard substrata as well as benthic organisms including other ascidians and algae. The serious ecological and economic damage experienced in New Zealand and other temperate regions has led to a large investment in on-going research into the biological tolerances and spread of D. vexillum as well as rapid response, monitoring and management following introductions. In summer 2008 an MSc student from Bangor University carrying out a survey of non native species in marinas in North Wales found a sea squirt in Ho lyhead Harbour that looked like the invasive non native species D. vexillum. A specimen was sent to a UK expert, who confirmed in November 2008 that it was very likely to be D. vexillum. Specimens were confirmed by Gretchen Lambert (pers. com. University of Washington, USA) as being D. vexillum. The purpose of this data capture was to assess the distribution and spread of the non-native species and possible threat to native species and biodiversity of the area.
Natural Resources Wales (NRW)
The following data is considered OS derived data and is therefore jointly owned by NRW and the Ordnance Survey. NRW may release, publish or disseminate this data freely; providing recipients are made aware of use restrictions
| Other details | ||
| Internal code | Internally assigned metadata identifier | 1840 |
| 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. | Non Native Species data - Distribution of Carpet Sea Squirt (Didemnum vexillum) in Holyhead Marina |
| Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | Dosbarthiad Didemnum vexillum ym Marina Caergybi |
| 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. | 4f4c4942-4343-5764-6473-313039353636 |
| Resource Identifier | This is the code assigned by the data owner. | 109566 |
| 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 | 2008-12-09 |
| End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2008-12-10 |
| Vertical extent (max) | A positive or negative decimal number, for example, the deepest depth recorded if subtidal, or, if intertidal, the highest point recorded. | 5.8 |
| Vertical extent reference | This descibes the vertical coordinate reference system as referred to in the EPSG register of geodetic parameters. (epsg-registry.org) | urn:ogc:def:crs:EPSG:: |
| Spatial resolution | This describes the spatial resolution of the dataset or the spatial limitations of the service. | inapplicable |
| 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'. | notPlanned |
| Abstract | The abstract provides a clear and brief statement of the content of the resource. | Didemnum vexillum is an invasive colonial ascidian that has become established world-wide having been identified in Japan, North America, northern Europe, and New Zealand, following a global expansion since the 1970’s. It forms sheet like colonies on natural and artificial hard substrata as well as benthic organisms including other ascidians and algae. The serious ecological and economic damage experienced in New Zealand and other temperate regions has led to a large investment in on-going research into the biological tolerances and spread of D. vexillum as well as rapid response, monitoring and management following introductions. In summer 2008 an MSc student from Bangor University carrying out a survey of non native species in marinas in North Wales found a sea squirt in Ho lyhead Harbour that looked like the invasive non native species D. vexillum. A specimen was sent to a UK expert, who confirmed in November 2008 that it was very likely to be D. vexillum. Specimens were confirmed by Gretchen Lambert (pers. com. University of Washington, USA) as being D. vexillum. The purpose of this data capture was to assess the distribution and spread of the non-native species and possible threat to native species and biodiversity of the area. |
| Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | A rapid assessment diver survey was completed by systematically surveying each of the pontoons. Data was collected by divers and communicated to the surface where it was mapped. Presence/Absence of Didemnum vexillum was recorded. Still images and video were also taken at random locations. Specimen samples were taken at various locations on each of the pontoon for further identification and confirmation by an expert. |
| Related keywords | ||
| Keyword | 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 | Zoobenthos generic abundance | |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | Marine Environmental Data and Information Network | |
| Geographical coverage | ||
| North | The northern-most limit of the data resource in decimal degrees | 53.32214656 |
| East | The eastern-most limit of the data resource in decimal degrees | -4.63994764 |
| South | The southern-most limit of the data resource in decimal degrees | 53.31891361 |
| West | The western-most limit of the data resource in decimal degrees | -4.64356281 |
| 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) | |
| Phone | 0300 065 3000 | |
| Delivery point | Maes-y-Ffynnon | |
| Postal code | LL57 2DW | |
| Role | The distributor is the person or organisation that distributes the resource. | distributor |
| Organisation name | Natural Resources Wales (NRW) | |
| Phone | 0300 065 3000 | |
| Delivery point | Maes-y-Ffynnon | |
| Postal code | LL57 2DW | |
| 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) | |
| Phone | 0300 065 3000 | |
| Delivery point | Maes-y-Ffynnon | |
| Postal code | LL57 2DW | |
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | Countryside Council for Wales (CCW) | |
| Phone | 0300 065 3000 | |
| Delivery point | Countryside Council for Wales, Maes y Ffynnon | |
| Postal code | LL57 2DW | |
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | University of Wales, Bangor. School of Ocean Sciences | |
| Phone | 01248 382842 | |
| Postal code | LL57 2DG | |
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | Marine Ecological Solutions Ltd | |
| Phone | 01248 712277 | |
| Delivery point | Marine Ecological Solutions Ltd | |
| Postal code | LL59 5EF | |
| Dataset constraints | ||
| 20 Limitations on Public Access - Access constraints | ISO restriction code chosen from ISO 19115-1 Codelist | otherRestrictions |
| 20 Limitations on Public Access – Other constraints | Any restriction on the use of the resource such as the need to agree to certain licence conditions. | The following data is considered OS derived data and is therefore jointly owned by NRW and the Ordnance Survey. NRW may release, publish or disseminate this data freely; providing recipients are made aware of use restrictions |
| 21 Conditions for Access and Use - Use limitation | Any restrictions imposed on accessing the resource such as the need to agree to certain licence conditions. | © CNC/NRW and © Crown copyright [2011]. All rights reserved. Natural Resources Wales, 100019741 Third parties seeking to re-use this data require a Licence issued by NRW. It allows re-use, reproduction and dissemination in any format or medium but only for non-commercial purposes, according to the terms and conditions of the Licence. Those seeking commercial re-use require a commercial licence available from the OS. |
| Available data formats | ||
| Data format | Format in which digital data can be provided for transfer | Documents |
| 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. | 2011-02-28 |
| Date of last revision | The most recent date that the resource was revised. | 2011-02-28 |
| Metadata date | The date when the content of this metadata record was last updated. | 2018-07-03 |
| Metadata standard name | The name of the metadata standard used to create this metadata | MEDIN Discovery Metadata Standard |
| Metadata standard version | The version of the MEDIN Discovery Metadata Standard used to create the metadata record | Version 2.3.8 |
© OpenStreetMap contributors