Density of hard-bottom fauna on dropstones at HAUSGARTEN station EG-IV, 2015 - 2021

Downward-facing seafloor images were recorded using the OFOBS towed camera system at HAUSGARTEN station EG-IV. One transect was collected in each year: 2015, 2016, 2017, 2019, and 2021. The online program BIIGLE (biigle.de) was used for annotation. Three red laser points appeared in each image and served as a size scale. For analysis, any images that were too bright, too dark, or outside the range 1.3 - 1.6 m from the seafloor were excluded. Ninety images were randomly selected for analysis from each transect. All hard-bottom-obligate fauna living on dropstones on the seafloor were annotated. The density of each taxon was calculated by dividing the number of individuals by the surface area of the image.