North Rona (Annex I) habitat map

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.