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Metadata: 2022 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Fal and Helford SAC Drop Down Video Maerl Habitat and Classification Survey
Abstract:
Cornwall Inshore Fisheries and Conservation Authority (Cornwall IFCA) carried out a survey between May and July in 2022 of the maerl feature of the Fal and Helford Special Area of Conservation (SAC). The aim of the survey was to get a better understanding of the varying types of maerl habitats present including: dense maerl (live and dead or dead), maerl sediment (live and dead or dead), sparse maerl (live and dead), scattered maerl (live and dead), maerl veneer (live and dead, static or live and dead, mobile) and areas of potential maerl which lack detail, and to provide and updated extent and distribution map within the Fal and Helford SAC. There were two parts to this survey and the current report details the second part. The first part consisted of an initial side-scan sonar survey in the Fal and Helford SAC, which was carried out by Cornwall IFCA in 2020 and 2021 (Sturgeon et al., 2021). The initial survey gathered acoustic data within the SAC, focusing on Falmouth Bay and covered an area from Pendennis Point to the Helford River out to the Fal and Helford SAC boundary from Zone Point towards Manacle Point. This second part uses the acoustic data gathered in part one to identify transitions between different acoustic signatures, with the aim of verifying habitat types represented by the given acoustic signals, using drop down video and stills. The survey is reported on by Jenkin et al., 2023.
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 | 2845 |
| 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. | 2022 Cornwall Inshore Fisheries and Conservation Authority (IFCA) Fal and Helford SAC Drop Down Video Maerl Habitat and Classification Survey |
| 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. | be2c5e1b32cac5724fb7bcc12fe50f06 |
| Resource Identifier | This is the code assigned by the data owner. | 2022_CIFCA_FAH_Maerl_DDV |
| 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 | 2022-05-12 |
| End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2022-07-13 |
| 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 between May and July in 2022 of the maerl feature of the Fal and Helford Special Area of Conservation (SAC). The aim of the survey was to get a better understanding of the varying types of maerl habitats present including: dense maerl (live and dead or dead), maerl sediment (live and dead or dead), sparse maerl (live and dead), scattered maerl (live and dead), maerl veneer (live and dead, static or live and dead, mobile) and areas of potential maerl which lack detail, and to provide and updated extent and distribution map within the Fal and Helford SAC. There were two parts to this survey and the current report details the second part. The first part consisted of an initial side-scan sonar survey in the Fal and Helford SAC, which was carried out by Cornwall IFCA in 2020 and 2021 (Sturgeon et al., 2021). The initial survey gathered acoustic data within the SAC, focusing on Falmouth Bay and covered an area from Pendennis Point to the Helford River out to the Fal and Helford SAC boundary from Zone Point towards Manacle Point. This second part uses the acoustic data gathered in part one to identify transitions between different acoustic signatures, with the aim of verifying habitat types represented by the given acoustic signals, using drop down video and stills. The survey is reported on by Jenkin et al., 2023. |
| Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | Video and digital still imagery was acquired using a STR SeaSpyder drop camera system (Appendix 2). The survey was carried out in line with Mapping European Seabed Habitats (MESH) recommended operating guidelines for underwater video and photographic imaging techniques (MESH, 2008). The tows were planned at 200 m with a still image every 10 m at a speed of 0.5 knots aiming for 10 to 15 minutes per tow. Planned survey sites were loaded into Hypack Max Version 2019 for navigation purposes with 10 10 m radius rings around each site with the aim of having one still image at each ring. If the tide or wind moved the vessel off course a 10 m radius ring was added to each target so the officer would know when the vessel had moved 10 m. Prior to the deployment of the SeaSpyder for each tow, the video text overlay was checked and adjusted to display the survey name and tow number (e.g. â??Cornwall IFCA01/06/2022. Fal BayDDV02T1â?) and the GPS, heading and depth info was checked to ensure that it was updating correctly. The .jpeg file name prefix was checked and adjusted to display the survey name, tow number, date, time (UTC) and automatic image number (e.g. â??CIFCAFalBay02T1202206011423200094.JPGâ?). The SeaSpyder camera was deployed through the A-Frame at the stern of Tiger Lily and lashed securely to the starboard side of the vessel between tows. The video was set to record once the camera was just above the seabed. Com Port A was set to log to record all positional information from the USBL GPS antenna (Lat/ Long WGS84) for the entire tow. A target was created in Hypack to indicate the start of line (SOL); this was repeated at the end of line (EOL). The SeaSpyder was â??flownâ?? with the frame legs just above the seabed for the tow. The camera frame was landed on the seabed every 10 m for a still image to be captured. Image separation varied slightly to ensure that the stills taken were of good quality (e.g. taken when the camera was focused on the seabed and the lens unobstructed) this sometimes led to a delay. Immediately upon having captured a still image a target was created in Hypack. Field notes were recorded for each target in Hypack such as image number, speed over ground and real-time observations of substrate and taxa (comma delimited) when possible. Hypack targets were used in data processing to obtain the exact time of each still image and the Easytrak Alpha USBL GPS log was used to obtain the exact location of each still image. All position information was recorded in the Lat/Long WGS84 projection and taken from a single GPS (USBL GPS antenna). GPS targets were recorded using the USBL GPS antenna set up on the wheelhouse roof of Tiger Lily. Hypack was set up to log a vessel position recorded every second and the Com Port A file was recording the USBL position from the camera for the duration of each tow. Hypack targets were extracted as a .txt file format and opened in Microsoft Excel (comma delimited). The Hypack â??loggingâ?? function was left running both survey days which outputs as a .RAW file. This data was opened with Microsoft Excel and cut to only include relevant strings of data such as date, time, position and depth. The data has not been extracted per tow but is available if required. Com Port A data was logged for the duration of each tow and saved in a .txt file format to the Topside PC. Still images from the SeaSpyder camera were initially stored on the internal computer (sub-surface), then on completion of each tow the still images were transferred to the SeaSpyder topside control unit using FileZilla and filed by site number. Video files were captured to the SeaSpyder topside unit data drive (D:/). The stills and video files were transferred from the topside unit to a WD Passport for transport and storage at the end of each survey day. The log sheets were worked on from the network and saved regularly throughout the day. Image analysis was carried out post-survey with each still image being assessed in terms of quality with categories good, acceptable or poor as follows; o Good: Clear, camera on seabed and sediment type and fauna distinguishable o Acceptable: Can make out the sediment type and what fauna are present but not the best quality o Poor: Canâ??t make out the sediment type or what fauna is present Any poor-quality images were not carried forward for further analysis. The position data for each tow were transferred to MapInfo Professional Version 17.0.2 and points were created to show the position of each still image (good and acceptable quality images only) and SOL/ EOL positions. |
| 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 characterisation | |
| Geographical coverage | ||
| North | The northern-most limit of the data resource in decimal degrees | 50.1707 |
| East | The eastern-most limit of the data resource in decimal degrees | -5.0132 |
| South | The southern-most limit of the data resource in decimal degrees | 50.088 |
| West | The western-most limit of the data resource in decimal degrees | -5.1223 |
| Regional sea | 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. | 2023-05-04 |
| 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. | 2024-08-13 |
| 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 |