Seto Inland Sea is the largest inland sea of Japan including more than two thousand islands. The complicated coastlines make multiple kind of habitats within a local seascape, which is a suitable environment for coastal marine organisms. Suo-nada and Aki-nada are parts of western part of Seto Inland Sea, especially including many natural and larger tidal flats and seagrass meadows with better condition, respectively. Main researches in the site include ecological researches on the biodiversity and ecosystem functionings of tidal flat and seagrass/algal beds have been conducted to monitor coastal environment and to secure the sustainable utilization of fisheries products.