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Metadata: 2007 - Sussex Sea Fisheries District Committee (SFDC), Sussex coastline, towed underwater video footage for habitat classification
Abstract:
Management through spatial planning is seen as a tool to facilitate competing resource demands in the marine environment. The process of spatial resource management requires the availability of relevant seabed descriptions. Currently habitat descriptions at a scale relevant to the inshore zone are not available to inshore managers. The Sussex Sea Fisheries District Committee has been progressing towards a policy of marine spatial resource management and planning and in recent years has been developing a series of Geographical Information Systems data sets which support this objective. The Sussex District encompasses several aggregate extraction sites and the Committee are called upon to provide information in the aggregate extraction consenting process. Single beam acoustic ground discrimination systems (AGDS) based on standard echo sounders are used for commercial and research applications to describe the seabed. In contrast to multibeam and sidescan systems AGDS are relatively simple, low in cost and can be attached to the hull of any vessel with minimal operator supervision once installed. The Sussex Sea Fisheries Committeeâ??s Fishery Patrol Vessel (FPV) â??Watchfulâ?? is equipped with an AGDS (QTCâ?¢ View 5) manufactured by the Quester Tangent Corporation of Canada. The QTCâ?¢ system is linked to a Simradâ?¢ 50 Khz single beam echo sounder and output data is processed and logged to an onboard PC using proprietary software â??Impactâ?? develop by QTCâ?¢. Subject to suitable operating conditions the system is normally operated during routine enforcement patrols. In the summer of 2007 FPV â??Watchfulâ?? provided a survey platform to sample 270 inshore field sites. The field sites were selected to coincide with locations where acoustic data had been collected. A Bowtechâ?¢ underwater camera system was modified for towed use with a custom designed video sledge. The system was deployed along a transect at each of the field sites to collect c. 100 m of video data. In excess of 13 hours of video survey was interpreted by a marine biologist. This data set, which represents c. 3 km of seabed imagery, was categorised using course resolution benthic morphology descriptors which might be detected by the QTCâ?¢ View system and could also be relevant to the identification of essential fish habitats within the Sussex Sea Fisheries District. In addition the sites were categorised according to the EUNIS marine habitat classification system to ensure the comparability of the data with other regional and international data sets. All video footage was transferred from DAT and archived to DVD. Selected video and stills information is hosted on the Committeeâ??s website to maximise rapid and wide dissemination (see http://www.sussexsfc.gov.uk/project_malsf02.htm). The multivariate statistical package Primerâ?¢ (Clarke, 2001) was used to cluster the categorised data interpreted from the video survey into broad habitat classes providing a custom designed habitat classification scheme with a course level of descriptive resolution that emphasised morphological seabed features rather than community structure. The geographical positions from the video survey sites were each attributed a class based on this classification scheme. Half of the data for each habitat class was used in a supervised classification process to develop a habitat classification. This was undertaken in the image processing software Idrisiâ?¢. The images used in the classification were created from the vector based acoustic data in the gridding software Surferâ?¢ (by averaging the acoustic data within a 20 m search radius of each grid node with a node spacing of 20 m). After classification in Idrisiâ?¢ the data was then reconverted to vector format and QTC Clamsâ?¢ was used to interpolate the class values using a categorical interpolator to create a final habitat map for interpretation purposes. The second half of the data interpreted from the video survey was then used to test the validity of the final habitat classification. An error matrix was produced and accuracy statistics were calculated for each class in the habitat map and for the map overall. The accuracy of the resulting map was low (Tau Coefficient = 0.28); the cause of this low accuracy was investigated and a re-survey carried out. A repeat survey of a proportion of the field sites from the video survey was undertaken. Time constraints and weather conditions meant 96 of the original 270 field sites were re-surveyed; this provided sufficient data to re-evaluate the system. During the analysis of this new data set the field data clustering, supervised classification and accuracy assessment was repeated several times and each time the constituents of the classification scheme were altered to assess the ability of the QTCâ?¢ AGDS system to detect different morphological seabed features. The classification schemes developed were as follows: â?¢ Substrate Only â?¢ Substrate and Sediment Features â?¢ Substrate and Lifeforms â?¢ Substrate Sediment Features and Lifeforms. In addition a final classification was undertaken using the EUNIS classification scheme. The EUNIS classification scheme produced the lowest classification accuracy (Tau = 0.16), the substrate classification produced the highest (Tau = 30%). The addition of the sediment features descriptors reduced the overall accuracy and the addition of the Lifeforms descriptors produced a similar result to the Substrate based classification (Tau = 29%). Overall the accuracy of the system was found to be poor. It is suggested that the low accuracy is a result of the wide variety of environmental conditions under which the survey was conducted. The frequent occurrence of sloped bedrock, angular boulders and dunes, waves and ripples is likely to have confused the acoustic record by in some cases reflecting sound away from the transducer. The variety 6 of depths surveyed (0-60 m) is another potential source of error. The water off the Sussex coast is often sediment dominated and in deep water this can cause significant absorption if reflected sound leading to a broad variation in the acoustic signature for the same seabed type. The system could be more effective if a standard survey design is used in constant environmental conditions; furthermore it is likely to provide more accurate results over smaller areas of seabed with low levels of depth variation. The influence of the classification system design on the thematic accuracy of the final map classifications demonstrates the importance of using a system which incorporates morphological features which are more readily detected by acoustic systems. The video system produced the most useful information from the project. The database and interpretation of the video record provided information at a higher resolution than expected; this alone provides an extensive and valuable additional source of information on the distribution of habitats off the Sussex coast. Given the value in the video database obtained in this study and the Sea Fisheries Committeeâ??s capacity to collect this type of information, in future a good bathymetric model of the seabed combined with information on seabed geology may be a reliable proxy for determining seabed habitats. An interactive seabed map, with video extracts and full copies of this report are available.
Data holder:
Sussex 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 | 3814 |
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. | 2007 - Sussex Sea Fisheries District Committee (SFDC), Sussex coastline, towed underwater video footage for habitat classification |
Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | Habitat Classification Using Video and Acoustic Techniques in Sussex using the European Nature Information System (EUNIS) habitat classification scheme, Marine Aggregate Levy Sustainability Fund (MALSF) Extension Project MAL 0020 |
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. | 752620811acf337a9c52bc3cd63b36fe |
Resource Identifier | This is the code assigned by the data owner. | SXIFCA0000003 |
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 | 2007-09-03 |
End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2007-10-09 |
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'. | notPlanned |
Abstract | The abstract provides a clear and brief statement of the content of the resource. | Management through spatial planning is seen as a tool to facilitate competing resource demands in the marine environment. The process of spatial resource management requires the availability of relevant seabed descriptions. Currently habitat descriptions at a scale relevant to the inshore zone are not available to inshore managers. The Sussex Sea Fisheries District Committee has been progressing towards a policy of marine spatial resource management and planning and in recent years has been developing a series of Geographical Information Systems data sets which support this objective. The Sussex District encompasses several aggregate extraction sites and the Committee are called upon to provide information in the aggregate extraction consenting process. Single beam acoustic ground discrimination systems (AGDS) based on standard echo sounders are used for commercial and research applications to describe the seabed. In contrast to multibeam and sidescan systems AGDS are relatively simple, low in cost and can be attached to the hull of any vessel with minimal operator supervision once installed. The Sussex Sea Fisheries Committeeâ??s Fishery Patrol Vessel (FPV) â??Watchfulâ?? is equipped with an AGDS (QTCâ?¢ View 5) manufactured by the Quester Tangent Corporation of Canada. The QTCâ?¢ system is linked to a Simradâ?¢ 50 Khz single beam echo sounder and output data is processed and logged to an onboard PC using proprietary software â??Impactâ?? develop by QTCâ?¢. Subject to suitable operating conditions the system is normally operated during routine enforcement patrols. In the summer of 2007 FPV â??Watchfulâ?? provided a survey platform to sample 270 inshore field sites. The field sites were selected to coincide with locations where acoustic data had been collected. A Bowtechâ?¢ underwater camera system was modified for towed use with a custom designed video sledge. The system was deployed along a transect at each of the field sites to collect c. 100 m of video data. In excess of 13 hours of video survey was interpreted by a marine biologist. This data set, which represents c. 3 km of seabed imagery, was categorised using course resolution benthic morphology descriptors which might be detected by the QTCâ?¢ View system and could also be relevant to the identification of essential fish habitats within the Sussex Sea Fisheries District. In addition the sites were categorised according to the EUNIS marine habitat classification system to ensure the comparability of the data with other regional and international data sets. All video footage was transferred from DAT and archived to DVD. Selected video and stills information is hosted on the Committeeâ??s website to maximise rapid and wide dissemination (see http://www.sussexsfc.gov.uk/project_malsf02.htm). The multivariate statistical package Primerâ?¢ (Clarke, 2001) was used to cluster the categorised data interpreted from the video survey into broad habitat classes providing a custom designed habitat classification scheme with a course level of descriptive resolution that emphasised morphological seabed features rather than community structure. The geographical positions from the video survey sites were each attributed a class based on this classification scheme. Half of the data for each habitat class was used in a supervised classification process to develop a habitat classification. This was undertaken in the image processing software Idrisiâ?¢. The images used in the classification were created from the vector based acoustic data in the gridding software Surferâ?¢ (by averaging the acoustic data within a 20 m search radius of each grid node with a node spacing of 20 m). After classification in Idrisiâ?¢ the data was then reconverted to vector format and QTC Clamsâ?¢ was used to interpolate the class values using a categorical interpolator to create a final habitat map for interpretation purposes. The second half of the data interpreted from the video survey was then used to test the validity of the final habitat classification. An error matrix was produced and accuracy statistics were calculated for each class in the habitat map and for the map overall. The accuracy of the resulting map was low (Tau Coefficient = 0.28); the cause of this low accuracy was investigated and a re-survey carried out. A repeat survey of a proportion of the field sites from the video survey was undertaken. Time constraints and weather conditions meant 96 of the original 270 field sites were re-surveyed; this provided sufficient data to re-evaluate the system. During the analysis of this new data set the field data clustering, supervised classification and accuracy assessment was repeated several times and each time the constituents of the classification scheme were altered to assess the ability of the QTCâ?¢ AGDS system to detect different morphological seabed features. The classification schemes developed were as follows: â?¢ Substrate Only â?¢ Substrate and Sediment Features â?¢ Substrate and Lifeforms â?¢ Substrate Sediment Features and Lifeforms. In addition a final classification was undertaken using the EUNIS classification scheme. The EUNIS classification scheme produced the lowest classification accuracy (Tau = 0.16), the substrate classification produced the highest (Tau = 30%). The addition of the sediment features descriptors reduced the overall accuracy and the addition of the Lifeforms descriptors produced a similar result to the Substrate based classification (Tau = 29%). Overall the accuracy of the system was found to be poor. It is suggested that the low accuracy is a result of the wide variety of environmental conditions under which the survey was conducted. The frequent occurrence of sloped bedrock, angular boulders and dunes, waves and ripples is likely to have confused the acoustic record by in some cases reflecting sound away from the transducer. The variety 6 of depths surveyed (0-60 m) is another potential source of error. The water off the Sussex coast is often sediment dominated and in deep water this can cause significant absorption if reflected sound leading to a broad variation in the acoustic signature for the same seabed type. The system could be more effective if a standard survey design is used in constant environmental conditions; furthermore it is likely to provide more accurate results over smaller areas of seabed with low levels of depth variation. The influence of the classification system design on the thematic accuracy of the final map classifications demonstrates the importance of using a system which incorporates morphological features which are more readily detected by acoustic systems. The video system produced the most useful information from the project. The database and interpretation of the video record provided information at a higher resolution than expected; this alone provides an extensive and valuable additional source of information on the distribution of habitats off the Sussex coast. Given the value in the video database obtained in this study and the Sea Fisheries Committeeâ??s capacity to collect this type of information, in future a good bathymetric model of the seabed combined with information on seabed geology may be a reliable proxy for determining seabed habitats. An interactive seabed map, with video extracts and full copies of this report are available. |
Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | The EUNIS habitat interpretation was conducted by a qualified and competent marine biologist. The full methodology can be found in the following report Clark, R. W. E. Dapling, T. M. Hume, D. R. Woolmer, A. P. and Vause, B. J. (2007) Habitat classification using video and acoustic techniques. Development of an Appropriate Hierarchical Classification Scheme for the Supervised Classification and Accuracy Assessment of AGDS Data. Extension Project MAL 0020 Aggregate Levy Sustainability Fund Partnership Grants Scheme. Cefas, Lowestoft. Available online at: http://www.sussex-sfc.gov.uk/documents/Sussex%20SFC%20MAL%200020%20ext%20Final%20Report%20%28reduced%20size%29.pdf |
Additional information | This describes relevant references to the data e.g. reports, articles, websites plus other useful information not captured elsewhere. | http://www.sussex-sfc.gov.uk/documents/Sussex%20SFC%20MAL%200020%20ext%20Final%20Report%20%28reduced%20size%29.pdf |
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 | Habitats and biotopes | |
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 | Marine | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Biodiversity | |
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 | 50.974 |
East | The eastern-most limit of the data resource in decimal degrees | 0.9915 |
South | The southern-most limit of the data resource in decimal degrees | 50.5466 |
West | The western-most limit of the data resource in decimal degrees | -0.9695 |
Regional sea | Eastern Channel | |
30E9 | ||
30F0 | ||
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 | Sussex Inshore Fisheries and Conservation Authority | |
Individual name | Sussex IFCA Data Manager | |
Position name | Data Manager | |
Role | The distributor is the person or organisation that distributes the resource. | distributor |
Organisation name | Sussex Inshore Fisheries and Conservation Authority | |
Individual name | Sussex IFCA Data Manager | |
Position name | Data Manager | |
Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
Organisation name | Sussex Inshore Fisheries and Conservation Authority | |
Individual name | Sussex IFCA Data Manager | |
Position name | Data Manager | |
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 | Sussex Inshore Fisheries and Conservation Authority | |
Individual name | Sussex IFCA Data Manager | |
Position name | Data Manager | |
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. |
Available data formats | ||
Data format | Format in which digital data can be provided for transfer | Database |
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. | 2007-12-31 |
Date of last revision | The most recent date that the resource was revised. | 2007-12-31 |
Date of creation | The date that the resource was created. | 2007-12-31 |
Harvest date | The date which this record has been (re)harvested from the provider. | 2024-04-14 |
Metadata date | The date when the content of this metadata record was last updated. | 2021-04-07 |
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 |