A New Method for Investigating Relationships Between Distribution of Sessile Organisms and Multiple Terrain Variables by Photogrammetry of Subtidal Bedrocks

Previous studies of habitat suitability sessile organisms on subtidal rocky substrata have been focused only one or two terrain attributes. In this study, we propose a new method to construct centimeter resolution seafloor topographic model by using underwater photogrammetry obtain multiple variables and investigate relationships between the distribution variables. Point cloud models five square sections (11.3–25.5 m 2 ) bedrock surface Otsuchi Bay were reconstructed with 0.05 resolution. Using 0.01 point models, calculated each face mesh models: height above seafloor, topological position index, slope, aspect, ruggedness. The presence/absence data four species (ascidian Halocynthia roretzi , barnacle Balanus trigonus polychaete Paradexiospira nakamurai articulated coralline algae Pachyarthron cretaceum located models. H. B. more abundant vertical high faces P. at surroundings. where current velocity increases, three animals may an advantage for their suspension feeding. contrast, unlike other animal species, occurred various heights gentle slope suitable photosynthesis.