Restoration of Estuaries and Bays in Japan—What’s Been Done So Far, and Future Perspectives

Abstract

Abstract Environmental conservation and management policy in Japan after World War II first placed emphasis on water pollution control as a countermeasure against hazardous water pollution, including toxic substances. Following this, the major target of pollution control was to prevent red tides and eutrophication by using restrictive measures such as total pollution load control in terms of chemical oxygen demand, total nitrogen, and total phosphorus. However, this kind of passive conservation policy is gradually being shifted to active conservation, which includes restoration of biodiversity, of biological productivity, and of habitat, as well as achieving a well-balanced nutrient cycle between land and sea. In the present study, three cases of restoration that have been done so far, in (1) Shima City, Mie Prefecture, (2) Bizen City, Okayama Prefecture, and (3) the entire area of Kagawa Prefecture, are examined. In 2014, the Ministry of the Environment, Japan, began a new research project, “Development of Coastal Management Methods to Achieve a Sustainable Coastal Sea,” which will continue to the end of fiscal 2018. This project aims to provide a suitable integrated coastal management to achieve the goal of sustainable coastal communities. Three research sites have been selected: (1) the Seto Inland Sea, as a semienclosed coastal sea, (2) Shizukawa Bay along the Sanriku Coast, as an open coastal sea, and (3) the Japan Sea’s coastal areas, where international management is necessary. The target of this project is to achieve a “clean, productive and prosperous coastal sea,” which we call Satoumi. Introducing the outline of this new project, future perspectives on restoration of estuaries and bays in Japan are discussed.