Alternate title

GB001333

Date (Publication)

2018-04-26

Date (Creation)

2014-02-13

Citation identifier

EMODnetSeabedHabitats / GB001333

Point of contact

Organisation name	Individual name	Electronic mail address	Role
DEFRA		open@defra.gsi.gov.uk	Owner
Natural England		enquiries@naturalengland.org.uk	Custodian

GEMET - INSPIRE themes, version 1.0

• Habitats and biotopes

http://inspire.ec.europa.eu/codelist/ReferenceHabitatTypeSchemeValue

• Eunis

Use limitation

┬® DAERA. Data may be re-used under the terms of the Open Government Licence.

Use limitation

geossAttribution

Access constraints

Other restrictions

Other constraints

no limitation

Spatial representation type

Vector

Denominator

4000

Language

English

Topic category

• Biota
• Oceans

Begin date

2013-01-23

End date

2013-04-03

Reference system identifier

EPSG / WGS 84 (EPSG:4326) / 7.9

Topology level

Geometry only

Distribution format

Name	Version
ESRI Shapefile	1.0

OnLine resource

Protocol	Linkage	Name
WWW:LINK-1.0-http--link	http://randd.defra.gov.uk/Document.aspx?Document=12850_PadstowBayandSurroundsMCZ_SummarySiteReport_V3.pdf	Padstow Bay and Surrounds MCZ Post-survey Site Report
WWW:LINK-1.0-http--link	https://www.emodnet-seabedhabitats.eu/access-data/launch-map-viewer/?zoom=18&center=-0.00005,0.00045&layerIds=501&baseLayerId=1&activeFilters=NobwRANghgngpgJwJIBMwC4CsAGAjAGjADMBLCAF0VQwBYB2Q0ixAGQHs2BrAVwAdUAzhmABdRmUoIAKnAAe5DGADiAIWx4AzFrABfEUA	EMODnet Seabed Habitats Map Viewer
OGC:WMS	https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_view_maplibrary/wms?	gb001333
OGC:WFS	https://ows.emodnet-seabedhabitats.eu/geoserver/emodnet_open_maplibrary/wfs?	gb001333
WWW:LINK-1.0-http--link	https://files.emodnet-seabedhabitats.eu/data/EMODnetSBHsurvey_GB001333.zip	EMODnet Seabed Habitats download

Hierarchy level

Dataset

Statement

The Padstow Bay and Surrounds MCZ overlaps with an area of existing Multibeam Echosounder (MBES) bathymetry and backscatter data acquired by the Maritime and Coastguard Agency (MCA) under the Civil Hydrography Programme (CHP). Consequently, no dedicated acoustic survey was carried out at the site. The MBES bathymetry covers most of the site. Backscatter is available from two survey blocks (Figure 2).

Ground-truth sampling for the site was planned using an existing bottom texture dataset created by the MCA based on their survey data. The bottom texture categories are not directly translatable to BSH, but the dataset enabled the placement of sampling stations equally on different bottom types The full array of stations, with the MCA interpretation of bottom texture, is illustrated below, in Figure 3.

Sampling equipment comprised a 0.1 m2 mini Hamon grab. On recovery, the grab was emptied into a large plastic bin and a representative sub-sample of sediment (approx. 0.5 litres) taken for Particle Size Analysis (PSA). The remaining sample was photographed and sieved over a 1 mm mesh sieve to collect the benthic fauna. Fauna were preserved in buffered 4% formaldehyde for later processing ashore. See the survey report for details of the sediment sampling methodology (Godsell 2013). Video footage and still images of the seabed were collected with an underwater camera system and sediment type determined by the use of grab samples. The camera images helped to characterise surficial sediments and associated epifaunal communities. The camera was mounted on a drop down frame with two high intensity LED strip lights and collected both video and still images. A reference scale was used in the video and still images. Set-up and operation followed the MESH ÔÇÿRecommended Operating Guidelines (ROG) for underwater video and photographic imaging techniquesÔÇÖ (Coggan et al., 2007). Video was recorded simultaneously to a Sony GV-HD700 DV tape and a computer hard drive. A video overlay was used to provide station metadata, time and GPS position (central reference point of the vessel) in the recorded video footage.

Camera tows lasted a minimum of 10 minutes, with the sledge towed at ca. 0.5 knots (ca. 0.25 m s ÔÇô1 ) across a 100 m diameter ÔÇÿbullringÔÇÖ centred on the sampling station. Still images were captured at regular 10ÔÇô15 m intervals and also opportunistically if specific features of interest were encountered. Video and still images were analysed Padstow Bay and Surrounds MCZ Post-survey Site Report 9 following an established protocol used by Cefas and the JNCC (Coggan and Howell 2005; JNCC, in prep.; see Annex 5). In all, 64 ground-truth stations were visited (Figure 3). Hamon grabs were successful at 27 stations and successful drop camera deployments were completed at all 64 stations. Station metadata are presented in Appendix 1. For further detail on ground-truth sample collection see the Padstow Bay and Surrounds rMCZ Survey Reports (Godsell, 2013; Ware, 2013).

All new maps and their derivatives have been based on a WGS84 datum. A new habitat map for the site was produced by analysing and interpreting the available acoustic data (as detailed above) and the ground-truth data collected during the dedicated survey of this site. To make use of the best available data, the habitat map was produced as a combination of three separate analyses of the existing acoustic data and the newly acquired ground-truthing data. A habitat map covering the whole area with MBES bathymetry coverage (Figure 2) was produced using only the bathymetry and its derivatives (Map 1). The CHP backscatter data was acquired during two surveys using different MBES systems on board different vessels and has therefore been treated as two separate datasets. Consequently, separate maps were produced for backscatter block 1 (Map 2) and block two (Map 3) including bathymetry, bathymetry derivatives and backscatter layers in the analysis. The three maps were combined to form the final habitat map by giving preference to the most accurate map where they overlapped.

To produce the updated habitat map, the segmentation objects in Maps 1, 2 and 3 were classified into ÔÇÿA3.2 Moderate energy infralittoral rockÔÇÖ, ÔÇÿA4.2 Moderate energy circalittoral rockÔÇÖ, ÔÇÿA5.1 Subtidal coarse sedimentÔÇÖ and ÔÇÿA5.2 Subtidal sandÔÇÖ according to the cut-off values identified in the three CI analysis for the appropriate variables. In Maps 2 and 3, patches of noise were clearly identifiable by their narrow rectangular shape, even spacing and much lower backscatter values from the surrounding objects. All objects identified as noise, were merged into their surrounding objects. The resulting final classified objects were exported into GIS, dissolved into continuous polygons and the map was simplified by reclassifying polygons smaller than 200 m2 into the surrounding habitat type. The three maps were merged into one map, with Maps 2 and 3 taking preference over Map 1 in areas of overlap.

Metadata

File identifier

d61365c0-ba62-4f81-a7d6-38c06d94115b XML

Metadata language

English

Character set

MD_CharacterSetCode_utf8

Hierarchy level

Dataset

Date stamp

2020-01-15T12:07:48

Metadata standard name

ISO19115

Metadata standard version

2003/Cor.1:2006

Metadata author

Organisation name	Individual name	Electronic mail address	Role
JNCC		HabitatMapping@jncc.gov.uk	Point of contact