During the RV MARIA S. MERIAN cruise MSM77 (2018-09-15 to 2018-10-13) to the long-term ecological research station HAUSGARTEN observatory in the Fram Strait the Ocean Floor Observation System (OFOS) was used to collect still images from various locations surveyed during the expedition. The OFOS consisted of a towed underwater camera system equipped with a high-resolution photo-camera (iSiTEC, CANON EOS 5D Mark III). The camera was mounted on a steel frame (140 L x 92 W x 135 H cm), together with two strobe lights, three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOS during deployments. An automatic seafloor image was taken every 20 seconds to obtain 'TIMER' stills distributed at regular distances along each of the survey profiles. Additional 'HOTKEY' photos were triggered individually when interesting objects appeared in the live feed. Here, image data of OFOS deployment MSM77_35-4 is presented.