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Metadata: 2021 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Cawsand within the Plymouth Sound and Estauries Special Area of Conservation Acoustic Survey of the seagrass bed
Abstract:
Cornwall Inshore Fisheries and Conservation Authority (Cornwall IFCA) carried out a survey to map the extent of the seagrass at Cawsand, within the Plymouth Sound and Estuaries Special Area of Conservation (SAC). The survey was carried out to provide Cornwall IFCA with an updated extent map of the seagrass. The seagrass at Cawsand is the only bed in the Plymouth Sound and Estuaries SAC which is within the Cornwall IFCA district, the remaining seagrass beds (Drakeâ??s Island, Cellar's Cove, Red Cove North, Red Cove South, Tomb Rock, Jennycliff South, Jennycliff North and Firestone Bay) are within the Devon and Severn IFCA district. The aim of the survey was to map the extent and coverage of the seagrass bed at Cawsand within the Plymouth Sound and Estuaries SAC using a Biosonics MX Scientific Echosounder. In total 64 MX tows were completed of which 62 were included in the analysis. Sea conditions were favourable throughout the survey.
Data holder:
Cornwall Inshore Fisheries and Conservation Authority
Click on the red button for resource contact details:
- Click on the red button for resource contact details
Use constraints:
No restrictions to public access
| Other details | ||
| Internal code | Internally assigned metadata identifier | 613 |
| 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. | 2021 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Cawsand within the Plymouth Sound and Estauries Special Area of Conservation Acoustic Survey of the seagrass bed |
| 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. | 259d15ca422e9a6a6669106a683918e6 |
| Resource Identifier | This is the code assigned by the data owner. | 2021_CIFCA_MX_CAW_Seagrass |
| 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 | 2021-08-23 |
| End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2021-08-23 |
| 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'. | continual |
| Abstract | The abstract provides a clear and brief statement of the content of the resource. | Cornwall Inshore Fisheries and Conservation Authority (Cornwall IFCA) carried out a survey to map the extent of the seagrass at Cawsand, within the Plymouth Sound and Estuaries Special Area of Conservation (SAC). The survey was carried out to provide Cornwall IFCA with an updated extent map of the seagrass. The seagrass at Cawsand is the only bed in the Plymouth Sound and Estuaries SAC which is within the Cornwall IFCA district, the remaining seagrass beds (Drakeâ??s Island, Cellar's Cove, Red Cove North, Red Cove South, Tomb Rock, Jennycliff South, Jennycliff North and Firestone Bay) are within the Devon and Severn IFCA district. The aim of the survey was to map the extent and coverage of the seagrass bed at Cawsand within the Plymouth Sound and Estuaries SAC using a Biosonics MX Scientific Echosounder. In total 64 MX tows were completed of which 62 were included in the analysis. Sea conditions were favourable throughout the survey. |
| Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | Historic survey data of seagrass at Cawsand within the Plymouth Sound and Estuaries SAC were downloaded using the latest marine data release provided by Natural England and EMODnet and a 40 m buffer was created around each bed. These positions were uploaded onto HYPACK MAX Version 2019 software. For each polygon, survey lines were created depending on the aspect of each individual bed so that the survey lines ran perpendicular where possible to the coastline following the Environment Agency methodology of subtidal seagrass monitoring for the Water Framework Directive (WFD) (Environment Agency, 2019). Each survey line ran further than the known extent of each bed to capture any changes to the bed extent since they were last surveyed. The survey lines were set up with 20 meter line spacing. Acoustic data was acquired using a MX Aquatic Habitat Echosounder (Appendix 2). The echosounder simultaneously acquires submerged aquatic vegetation (including seagrass), substrate and bathymetry data using Visual Acquisition by BioSonics (Version 6.4) software. The transducer was deployed over the port side of the vessel via a pole mounted on the side which can be deployed for survey operations. Acoustic data was collected in one survey area to map the extent of the bed. Remote access software was used on all laptops to enable the home based scientific officers to independently operate the MX Echosounder controls and HYPACK. Microsoft Teams was also used throughout each survey day to enable the home-based officers to maintain continuous communication with the survey crew aboard the vessel. On arrival at Cawsand, a Valeport Swift Sound Velocity Profiler was deployed to measure the Conductivity, Temperature, and Depth (CTD). Once recovered to deck the data was downloaded using Valeport Data log X2 software and the temperature and salinity values from the bottom depth were input into the Visual Acquisition software. A folder for the survey area was created prior to the deployment of the MX and data was recorded with date and time stamps for each file e.g. 20210823_113700. A target was created in HYPACK to indicate the start of line (SOL); this was repeated at the end of line (EOL). The speed over ground was aimed to be at a constant of 4.5 knots so that the pings from the MX were at a consistent distance. MX SOL and EOL positions, targets for verification and video tow SOL and EOL positions were recorded in the Lat/Long WGS84 projection taken from a single GPS, Hemisphere V500 GNSS system on Tiger Lily VI. HYPACK targets were extracted as a .txt file format and opened in Microsoft Excel (comma delimited). The video files and raw MX files (.dt4 and .rtpx) were transferred from the PC to a WD Passport for transport and storage at the end of each survey day. The log sheets were worked on from the shared network drive and saved at the end of each day. A total of 64 lines were completed and a total of 62 lines were included in the data analysis. All lines for each bed were loaded into Visual Aquatic by BioSonics software in a batch, then analysed individually. Quality assurance (QA) was carried out for tows individually and the bottom line and plant line were manually adjusted where there were errors. The plant line was adjusted when anything other than seagrass was present such as algae, noise in the water column when the vessel was turning and fish in the water column. Once each line was corrected, the post processing information was recorded in the survey log. The analysed data were exported from Visual Aquatic as a .csv file which records the data as an average of every ten pings. The data was copied to Microsoft Excel pasted to columns with corrected headers including latitude, longitude, date, time and notes. This was saved as a .xls file and imported into MapInfo Professional Advanced (Version 17.0.4) to create points. A theme was added to the points data for the plant height (m) and the plant coverage (%). A polygon was drawn around each survey area clipped to the point at the start and end of each tow. A raster was created using the natural neighbour function for plant height (m) and plant coverage (%). The settings for the raster were distance: 20 m, smoothing: 0, clipped to polygon for each survey area, cell size: user suggested and interpolated along edges. Advanced colour was used to define the colour scales. Plots were created for points of plant height (m), percentage cover (%) of seagrass, contour plot of plant height (m) and the contour plot of percentage cover of seagrass (%). |
| Related keywords | ||
| Keyword | General subject area(s) associated with the resource, uses multiple controlled vocabularies | Marine Environmental Data and Information Network |
| General subject area(s) associated with the resource, uses multiple controlled vocabularies | NDGO0005 | |
| Keyword title | data.gov.uk | |
| 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 | Habitat extent | |
| Geographical coverage | ||
| North | The northern-most limit of the data resource in decimal degrees | 50.3373 |
| East | The eastern-most limit of the data resource in decimal degrees | -4.19 |
| South | The southern-most limit of the data resource in decimal degrees | 50.3255 |
| West | The western-most limit of the data resource in decimal degrees | -4.2003 |
| Regional sea | Western Channel and Celtic Sea | |
| 29E5 | ||
| water column | ||
| 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 | Cornwall Inshore Fisheries and Conservation Authority | |
| Position name | Data Officer Cornwall IFCA Research Team | |
| enquiries@cornwall-ifca.gov.uk | ||
| Role | The distributor is the person or organisation that distributes the resource. | distributor |
| Organisation name | Cornwall Inshore Fisheries and Conservation Authority | |
| Individual name | Research Team Cornwall IFCA | |
| enquiries@cornwall-ifca.gov.uk | ||
| Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
| Organisation name | Cornwall Inshore Fisheries and Conservation Authority | |
| Individual name | Research Team Cornwall IFCA | |
| enquiries@cornwall-ifca.gov.uk | ||
| 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 | Cornwall Inshore Fisheries and Conservation Authority | |
| Individual name | Research Team Cornwall IFCA | |
| enquiries@cornwall-ifca.gov.uk | ||
| Dataset constraints | ||
| 20 Limitations on Public Access - Access constraints | otherRestrictions | |
| 20 Limitations on Public Access - Other constraints | This states any limitations on access to the data and uses free text. | No restrictions to public access |
| 21 Conditions for Access and Use - Use limitation | 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. | Data is freely available for research or commercial use providing that the originators are acknowledged in any publications produced and permission must be sought if the data will be reproduced in full or part or if used in any analyses. |
| 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. | 2021-10-05 |
| 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. | 2024-07-23 |
| 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 | 2.3.8 |