Non Native Species data - Distribution of Carpet Sea Squirt (Didemnum vexillum) in Holyhead Marina

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 Holyhead 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.

Identifier: NRW_DS109566

Alternative Title

Dosbarthiad Didemnum vexillum ym Marina Caergybi

Metadata Language: English

Lineage: 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.

Dataset Reference Date (Publication): 2011-02-28

Temporal Extent

Begin date: 2008-12-09

End date: 2008-12-10

Topic category

Biota

Owner

Natural Resources Wales (NRW)

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

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

Originator

Countryside Council for Wales (CCW)

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

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

Originator

University of Wales, Bangor. School of Ocean Sciences

Bangor, Gwynedd, LL57 2DG

http://www.bangor.ac.uk

Originator

Marine Ecological Solutions Ltd

Marine Ecological Solutions Ltd, 41 High Street, Menai Bridge, Ynys Mon, LL59 5EF, Wales

http://www.marine-ecosol.co.uk

Extent

Geographic Extent: SIR YNYS MON - ISLE OF ANGLESEY

Vertical Extent

Medin Extent Keyword: benthic boundary layer

Vertical Extent

Minimum value (metres): 0

Maximum value (metres): 5.8

Vertical CRS

Format Type and Description

Documents Documents ()

Specification

[A] Abundance and distribution held as MapInfo Line layers. [B] Location of video, photographs and specimen samples held as MapInfo point layers. [C] Images held as digital video and digital photographs.

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: 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.

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

Didemnum vexillum
non-native species
sea squirt

Type: Theme

Citation

Date (Publication): 2023-12-31

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

Keywords

SeaDataNet Parameter Discovery Vocabulary

Zoobenthos generic abundance

Type: Theme

Citation

Date (Revision): 2021-01-06

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

Code: British National Grid (EPSG::27700)

Content Information

NRW Profile

Custom Elements

NRW Related Title: Survey of a non-native ascidian (sea squirt) didemnum vexillum in Holyhead harbour January 2009

Constraints

Limitations on Public Access and Use

Restriction type: Other restrictions

Access Constraints Directive

Limitations: no limitations

Access Constraints Text

Other constraints: 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

Use Constraints

Use constraints type: Other restrictions

Other constraints: © CNC/NRW and © Crown copyright [2011]. All rights reserved. Natural Resources Wales, AC0000849444 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.

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313039353636 XML

Metadata Language: English

Resource type: Dataset

Metadata Date: 2024-05-31T09:41:35.914Z

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.

Non Native Species data - Distribution of Carpet Sea Squirt (Didemnum vexillum) in Holyhead Marina

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