NRW_DS113445 eng dataset Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en pointOfContact 2026-03-03T16:06:50 MEDIN 3.1.2 wel eng utf8 British National Grid (EPSG::27700) Modelling the Predicted Spread of a Carpet Sea Squirt ( Didemnum vexillum ) around the Welsh Coast (2011) Modelling the Predicted Spread of a Carpet Sea Squirt ( Didemnum vexillum ) around the Welsh Coast (2011) Modelu lledaeniad disgwyliedig Didemnum vexillum o amgylch arfordir Cymru 2011 2011-01-28 publication 4f4c4942-4343-5764-6473-313133343435 Didemnum vexillum is an invasive sea squirt that is not native to UK shores. It was first detected in Europe in 1991 and has since spread to several countries (including France, Ireland and the UK). The species has been located in Wales, Scotland and England and there is concern D. vexillum may have negative impacts on biodiversity and shellfish interests. Predicting the spread of an invasive species is crucial when assessing possible management actions. The potential impacts of the species on both biodiversity and commercial interests need to be studied and a cost-benefit approach taken to decide on the best course of management for that species. Geographic Information System (GIS) offers a fast, efficient way to map this predicted spread. The results of this mapping can then be used to focus on areas where D. vexillum may conflict with conservation and commercial interests. Didemnum vexillum is an invasive sea squirt that is not native to UK shores. It was first detected in Europe in 1991 and has since spread to several countries (including France, Ireland and the UK). The species has been located in Wales, Scotland and England and there is concern D. vexillum may have negative impacts on biodiversity and shellfish interests. Predicting the spread of an invasive species is crucial when assessing possible management actions. The potential impacts of the species on both biodiversity and commercial interests need to be studied and a cost-benefit approach taken to decide on the best course of management for that species. Geographic Information System (GIS) offers a fast, efficient way to map this predicted spread. The results of this mapping can then be used to focus on areas where D. vexillum may conflict with conservation and commercial interests. Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en owner Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en custodian Countryside Council for Wales (CCW) Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk/splash?orig=/ originator SeaZone Howberry Park, Wallingford, Oxfordshire, OX10 8BA info@SeaZone.com http://www.seazone.com/index.php originator Natural England Foundry House, 3 Millsands, Riverside Exchange, Sheffield, S3 8NH enquiries@naturalengland.org.uk http://www.naturalengland.org.uk/ originator Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en distributor notPlanned Species distribution theme GEMET - INSPIRE themes, version 1.0 2008-06-01 publication geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme WALES non-native species Holyhead invasive species (alien species) colonial sea squirt Didemnum vexillum ascidians marinas and marine docks sea squirt theme NRW Thesaurus 2025-01-08 publication geonetwork.thesaurus.local.theme.converted_nrw-keywords Salinity of the water column Temperature of the water column theme SeaDataNet Parameter Discovery Vocabulary 2024-06-19 publication geonetwork.thesaurus.external.theme.rdf+xml otherRestrictions There are no access restrictions to this data. NRW may release, publish or disseminate it freely. no limitations otherRestrictions © CNC/NRW 2011 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. vector eng utf8 environment biota NRW Geographic Identifiers Collection 2024-01-01 publication United Kingdom (UKM) NRW Geographic Identifiers Collection 2024-01-01 publication Wales (WLS) -5.6388218 -2.48898781 51.10318921 53.55513005 SeaVoX Vertical Co-ordinate Coverages 2013-02-05 creation water column 2009-01-01 2011-01-28 -30 0 Documents [A] Summary report (electronic version - MS Word) Geographic Information System [B] Map of locations of known presence of D.Vexillum (MapInfo table). dataset 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 2010-12-08 publication This dataset has not been assessed for conformance to the referenced INSPIRE regulation. false Countryside Council for Wales (CCW) has been investigating and controlling the spread of D. vexillum in Holyhead Marina since 2009. For this project, all the GIS spatial processing was carried out in ArcMAP 9.3 and used the ArcMAP toolbox along with Hawth's Tools and ET Geowizzards toolboxes. Data was used from 2009 - 2011 and a predictability model used which may have some limitations. In order to predict the potential spread of D. vexillum a simple modelling approach can be used, which uses the species biological limits and current known populations to estimate the positions of future colonies. Whilst this approach quickly produces results, it is limited as the model is not quantitative and can not be adequately tested. Countryside Council for Wales (CCW) has been investigating and controlling the spread of D. vexillum in Holyhead Marina since 2009. For this project, all the GIS spatial processing was carried out in ArcMAP 9.3 and used the ArcMAP toolbox along with Hawth's Tools and ET Geowizzards toolboxes. Data was used from 2009 - 2011 and a predictability model used which may have some limitations. In order to predict the potential spread of D. vexillum a simple modelling approach can be used, which uses the species biological limits and current known populations to estimate the positions of future colonies. Whilst this approach quickly produces results, it is limited as the model is not quantitative and can not be adequately tested.