Scottish Natural Heritage
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The aim of the survey was to map the seabed environment around North Rona. The survey will form the baseline for future management of the area to determine the scope and nature of any “appropriate assessment”. The survey area encompasses the seabed all around North Rona. In order to record and characterise the habitats around North Rona, Seastar Survey Ltd. undertook an acoustic and a ground-truthing survey (video/still photography survey) in 2009. The aim of the acoustic element of the survey was to identify different backscatter returns and describe as well as delineate the extent of the various seabed habitat types occurring around North Rona. A digital sidescan sonar mosaic, in conjunction with single beam echo sounder derived bathymetry, provided the initial broadview to map the substrata present throughout the survey area as well as allowing the identification of any features of interest. The aim of the ground-truthing element of the survey was to provide a description of the richness and diversity of the habitats on both rocky reef and the softer sediments. The biotope distribution and species composition was developed through interpretation of drop-down video footage and digital still photography, taken after evaluation of the sidescan mosaic. The results of all elements of the survey were used to create a Geographical Information System (GIS) which enabled a high level of processing, interpretation and display of the sidescan sonar mosaic, bathymetry, substrata types, biotopes and the digital photography.
This brief report presents the analysis completed to date. Little biological data exists for the majority of the deeper water of the Loch and for this reason the initial classification has been confined to habitat type.
Methodologies for broad scale mapping of sublittoral habitats and biota based on acoustic remote sensing was developed as the Broadscale Mapping Project (BMP), a three year project funded by a consortium consisting of the Crown Estate, the Countryside Council for Wales, English Nature, Scottish Natural Heritage and Newcastle University through the SeaMap Research Group. The project was also supported by the European Commission?s Life programme. The Firth of Lorn study area was selected by Scottish Natural Heritage (SNH) because it encompassed a wide range of physical environmental conditions and had considerable existing conservation value. Part of the BMP study area was recently put forward as a possible Special Area of Conservation in recognition of the significant marine biological interest of both intertidal and subtidal rocky reefs. A nested survey strategy was developed for the Firth of Lorn which involved careful pre-planning and iterative field survey. By adopting this nested and iterative approach, the overall summary maps comprise a jigsaw of small maps where the underlying data vary in their level of detail. The main features and biota were mapped using acoustic remote sensing techniques combined with biological sampling. Linking the biological data with the acoustic data was completed using classification techniques developed for processing satellite images.
The survey of the marine environment in the Sound of Arisaig proposed SAC was undertaken by the BioMar Project, at the University of Newcastle, under contract to SNH. The Sound of Arisaig has an unusually high diversity of sublittoral sediment habitats within a relatively small area, and has rich maerl beds. This study was to map the pSAC and undertake further detailed studies of the maerl beds. Acoustic techniques were used validated by biological sampling using towed video and scuba divers. The data was stored and analysed using GIS.
This map covers the area in the north of The Sound of Barra, at the south-eastern end of South Uist. The Sound of Barrahas been selected as a possible Special Area of Conservation (pSAC) on the basis of the nationally important colony of common seals, Phoca vitulina, and also for the wide variety of habitats associated with shallow ?sandbanks which are slightly covered by seawater all the time?. A number of the sandbank habitats are of considerable conservation value, most notably the extensive beds of the eelgrass Zostera marina and tide-swept maerl beds composed of the coralline red alga Phymatolithon calcareum. A comprehensive biotope mapping survey of the sublittoral habitats within the Sound was undertaken in August 2001, by a collaborative research group from the University of St Andrews, Heriot-Watt University, Edinburgh University and Scottish Natural Heritage (SNH). This information supplemented the existing knowledge on the distribution of marine communities within the Sound of Barra pSAC and all this information was synthesised into a series of biotope classification maps.
Loch Sunart is a complex fjordic sea loch on the west coast of Scotland. The loch supports some of the best Scottish and UK examples of bedrock reef habitats and associated communities. The site has been selected as a candidate Special Area of Conservation (cSAC) on the basis of the quality of the reefs present. A biotope mapping survey of the sublittoral habitats within the loch was undertaken in July and August 2001, by a collaborative research group from the University of St Andrews, Heriot-Watt University and Scottish Natural Heritage (SNH). Rapid broad scale remote acoustic mapping techniques were utilised and ground truth data were collected to enable the interpretation of the acoustically-classed seabed maps. These data supplemented the considerable body of existing knowledge on Loch Sunart marine communities and this information was depicted in a series of biotope distribution maps.
A survey of the seabed habitats of Loch Duich.
A broadscale benthic survey of Loch Creran was carried out in 1998-1999. The primary objective of the study was to map the sublittoral habitats and delimit biotopes. AGDS was used, ground-truthed by grab sampling, ROV, diver video and stills photography.
Survey of the intertidal and subtidal zones of the Treshnish Isles cSAC to provide a broad scale biotope distribution map for the area. This dataset is a map of predicted subtidal lifeforms for the area surrounding the Treshnish Isles.
Broadscale intertidal survey of Loch Laxford cSAC, biotope mapping.