Shin-ichiro Tanimae1, Dominic Franco C. Belleza1, Hiroto Tateishi1 and Gregory N. Nishihara2
1Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
2Organization for Marine Science and Technology, Institute for East China Sea Research, Nagasaki University, Nagasaki, Japan
Climate change is one of a many factors that has led to the transition and decline of macroalgae communities throughout Japan and the collapse of these communities are believed to negatively influence coastal fisheries productivity. Japan has a rich history of transplanting seaweeds, spore bag deployment, and artificial reefs installation to restore and expand macroalgae communities. To maximize the effectiveness of these conservation efforts, information about the relationship between environmental factors and macroalgal communities at small spatial scales is important. We hypothesized that physical environmental factors at relatively small spatial scales (i.e., 100 m) influence the composition of macroalgae communities in Arikawa Bay, Nagasaki, Japan. We conducted field surveys from April 2021 to July 2022 at seven stations that were separated by about 200 m. At each station we recorded the macroalgae species, water temperature, water motion, sedimentation, and water depth. The community matrix of each station was determined and a redundancy analysis (RDA) was performed to elucidate the relationship between the community composition and environmental factors. From the RDA, we inferred that water motion and variations in daily water temperature influences the composition of macroalgae communities. Therefore, we suggest that exposure to wave forces and thermal stress can influence the composition of these communities at relatively small spatial scales.