The Belgian western Coastal Banks are among the most diverse along the Belgian coastline, not only because of their complex geomorphological structure, but also due to a high biological diversity. A restricted area has been proposed to become a Marine Protected Area and for the definition and follow-up of its ecological value, an intensive and integrated biology-geology project was set up (HABITAT Project, Degraer et al. 2002). On a biological level, three macrobenthic communities and one species association were defined and from a geological point of view most attention was paid to the optimal use of remote sensing techniques. From this, time- and cost-efficient monitoring tools were put forward and are being evaluated within the present study. The simultaneous application of side-scan sonar and very-high resolution multibeam is regarded an important tool. Although they are established imaging techniques, their capability towards seafloor classification and especially to detect macrobenthic communities needs further investigation; hence ground-truthing remains essential. Based on the already known links between the sedimentology and the macrobenthos on the one side and between the sedimentology and the side-scan sonar recordings on the other hand, a macrobenthic interpretation of side-scan sonar images could be worked out; from this a sonar classification table with a prediction towards a community preference was established. Still, this approach remains qualitative and experience is needed for its interpretation. The acoustic backscatter of very-high resolution multibeam images can also be studied and since it is expressed in numerical values (decibel), it can be statistically treated and further processed to develop a quantitative automated seafloor classification. One of the aims of the present study is to evaluate the side-scan sonar based classification table in a very restricted area (Trapegeer sandbank-Westdiep swale) in the western Coastal Banks. Moreover, very-high resolution multibeam data was also available and was processed and classified using an automated seafloor classification programma. The predictions towards the occurrence of macrobenthic communities were ground-thruthed using Van Veen grab samples that were analysed for their macrobenthic content and their sedimentology.
All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy
