A non-invasive monitoring method to assess the composition of megabenthic communities in semi-submerged marine caves

hard-bottom habitats have been historically studied with invasive monitoring techniques. However, the great advances in digital photography of the last two decades have provided useful non-destructive tools for the study of their biological communities. We here describe the application of a non-invasive monitoring method targeting the preliminary assessment of the benthic communities of two semi-submerged marine caves at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy). It involved the realization of video transects by SCUBA diving, from which still images were extracted and analyzed with the image-processing software photoQuad 1.4 to estimate the benthic composition of the two semi-submerged marine caves. This method showed several advantages, proving to be suitable for monitoring semi-submerged marine caves.