Distribution of the Invasive Non Native Species (INNS) American slipper limpet Crepidula fornicata in Conwy Estuary (2012)
The Menai Strait and Conwy estuary area is a designated Special Area of Conservation (SAC) in Wales. The Habitats Directive establishes that the management of SACs should aim to achieve the favourable conservation status of habitat and species features listed within its Annex I habitats and Annex II species. Crepidula fornicata, the American slipper limpet is an invasive non native species in Wales. The slipper limpet occurs on a variety of substrates, it is often found attached to the shells of mussels, Mytilus edulis as well as oysters, stones and other shells around the low water mark. This species is found in south Wales, especially the Milford Haven area, with few records north of the Haven. The Menai Strait mussel fishery in north Wales is the largest in the UK. The mussel ‘seed’ is imported from outside the area. The problem with importing the seed from elsewhere is that there is the risk of accidentally introducing the invasive slipper limpet. This was the case in 2006 when C. fornicata escaped into the Menai Strait. The purpose of this data capture was to assess spread of Crepidula fornicate in North Wales by assessing the Conwy estuary.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS115583
- Metadata Language
- English
- Lineage
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Intertidal Sampling The mussel beds were sampled between 8th August and 9th August 2013 during the early morning low tides. 34 random site locations were chosen and at each site 3 x 0.25m squared quadrats were sampled giving a total of 102 quadrat samples. The substratum, mussel percentage, barnacle percentage and presence of C. fornicata were recorded on a proforma recording sheet. Site locations were recorded using the GPS and then imported into the GIS software package, MapInfo. A number of photos were taken on site. Pictures included general location views together with pictures of quadrats and other subjects thought to be relevant at the time of survey. Subtidal Sampling A 0.1m squared day grab was deployed from Mersey Guardian, an Environment Agency survey vessel, at each site. The day grabs were originally organised for Water Framework Directive monitoring. In some cases however, the grab jaws were not able to shut fully due to the substrate being coarse (cobbles, gravel and sand with many large mussels) and jamming the grab. In these unusable grab samples, hand searching through the material was conducted quickly, specifically looking for C. fornicata. 33 of these grab samples were checked for the invasive species.
- Dataset Reference Date (Publication)
- 2013-08-09
Extent
Extent
- Geographic Extent
- Wales (WLS)
))
Vertical Extent
- Medin Extent Keyword
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unknown
Distribution
- Format Type and Description
-
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Documents
()
- Specification
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The data archive consists of: [A] Report and proformae for recording at both the intertidal and Subtidal sites in word [B] Spreadsheets [C] Photographs in jpeg format of quadrats and of the site in general [D] Marine Recorder file
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Documents
()
Quality
Data quality
- Quality Scope
- Dataset
- Lineage
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Intertidal Sampling The mussel beds were sampled between 8th August and 9th August 2013 during the early morning low tides. 34 random site locations were chosen and at each site 3 x 0.25m squared quadrats were sampled giving a total of 102 quadrat samples. The substratum, mussel percentage, barnacle percentage and presence of C. fornicata were recorded on a proforma recording sheet. Site locations were recorded using the GPS and then imported into the GIS software package, MapInfo. A number of photos were taken on site. Pictures included general location views together with pictures of quadrats and other subjects thought to be relevant at the time of survey. Subtidal Sampling A 0.1m squared day grab was deployed from Mersey Guardian, an Environment Agency survey vessel, at each site. The day grabs were originally organised for Water Framework Directive monitoring. In some cases however, the grab jaws were not able to shut fully due to the substrate being coarse (cobbles, gravel and sand with many large mussels) and jamming the grab. In these unusable grab samples, hand searching through the material was conducted quickly, specifically looking for C. fornicata. 33 of these grab samples were checked for the invasive species.
Keywords
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2008-06-01
Keywords
- NRW Thesaurus
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- non-native species
- limpets
- slipper limpet
- crepidula fornicata
- Conwy estuary
- Menai Strait and Conwy Bay SAC
- Type
- Theme
Citation
- Date (Publication)
- 2023-12-31
Keywords
- SeaDataNet Parameter Discovery Vocabulary
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- Sediment grain size parameters
- Sedimentary structure
- Type
- Theme
Citation
- Date (Revision)
- 2021-01-06
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
- NRW Related Title
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NRW Conwy Estuary Crepidula Fornicata Survey August 2013
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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There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Use Constraints
- Use constraints type
- Other restrictions
- Other constraints
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© CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose.
Metadata
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313135353833 XML
- Metadata Language
- English
- Resource type
- Dataset
- Metadata Date
- 2024-05-31T09:38:34.62Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
-
1.0