The aim of this work was to characterise the fauna of the circalittoral community of the coastal detritic bottom in the Slovenian sea using two different approaches, i.e. the analysis of samples obtained by dredge and the examination of seabed videos obtained by video dredge and video sledge. The video review approach has been developed in the framework of this thesis, and the video sledge method has also been upgraded and tested during the thesis. Using different methods, the main features of the structure of the epibenthic assemblage, which consists of sponges, molluscs, tunicates, crustaceans and echinoderms, were identified. The most abundant and dominant species in the area is the brittle star O. quinquemaculata. We also detected facies with the alga P. squamaria, which is the dominant species in the facies area and also influences the community structure itself. We compared the parameters obtained by both methods. We found that both approaches provide good insight into the structure of the epibenthic community on the coastal detrital bottom, but each has its own limitations. The advantage of dredge sampling is that a larger number of taxa (including small and cryptic ones) are detected, the identifiability of organisms is more precise and a key parameter of community evaluation, i.e. wet mass, is obtained. The advantage of video is that it can capture data from a much larger area in a shorter time, certain relevant organisms that cannot be detected and counted in dredge samples (e.g. many sponges) can be detected and counted, and insights into the physical structure of the seabed and the distribution of organisms and their behaviour can be gained. The upgrade of the videos with video sleds has shown that we can identify the structure and condition of the epibenthic community, as well as changes in space and time, with sufficient quality. It is also crucial that this method is non-destructive. We concluded that the advantages described above make it reasonable to use the video sledge method as the primary method for assessing the status of the epibenthic assemblage. However, for a more comprehensive view, it is prudent to use complementary sampling methods such as dredging, underwater surveys or sampling with autonomous diving equipment.
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