Application of Hyperspectral Imaging to Underwater Habitat Mapping, Southern Adriatic Sea

Hyperspectral imagers enable the collection of high-resolution spectral images exploitable for the supervised classification of habitats and objects of interest (OOI). Although this is a well-established technology for the study of subaerial environments, Ecotone AS has developed an underwater hyperspectral imager (UHI) system to explore the properties of the seafloor. The aim of the project is to evaluate the potential of this instrument for mapping and monitoring benthic habitats in shallow and deep-water environments. For the first time, we tested this system at two sites in the Southern Adriatic Sea (Mediterranean Sea): the cold-water coral (CWC) habitat in the Bari Canyon and the Coralligenous habitat off Brindisi. We created a spectral library for each site, considering the different substrates and the main OOI reaching, where possible, the lower taxonomic rank. We applied the spectral angle mapper (SAM) supervised classification to map the areal extent of the Coralligenous and to recognize the major CWC habitat-formers. Despite some technical problems, the first results demonstrate the suitability of the UHI camera for habitat mapping and seabed monitoring, through the achievement of quantifiable and repeatable classifications

A protool for the monitoring of Mediterranea rhodolith beds

Mapping of Mediterranean rhodolith beds (RBs) should be focussed on areas of the seafloor with >10% cover of live calcareous red algae for a minimum surface of 500m2, on 1:10000 scale. More detailed scales (at least 1:1000) should be used for monitoring selected RBs, in order to detect significant changes through time. Beside the location and areal extent, the description of a RB that could be provided by non-specialists should include the occurrence of macroscopic sedimentary structures of the seafloor, thickness of live cover, mean percentage cover of live thalli, and dominant morphologies of rhodoliths (unattached branches, pralines or boxwork rhodoliths). For the purpose of ecological status assessment and the evaluation of human-induced impacts, the protocol requires the support of specialists to add details on the assemblage compositio