Seabird Distribution in Coastal Area of Japan Revealed by Aerial Survey

The use of renewable energy has been promoted in the context of global warming. In Japan, offshore wind farms are expected to be an efficient and economical renewable energy source as the country is surrounded by the sea, and a large area of the seabed has potential for offshore wind farms. The distribution of seabirds is important for evaluating the impact of offshore wind farms. In Japan, many previous studies on offshore seabirds have been conducted using ships and biologgers. However, few wide-ranging surveys have been conducted in Japan, and information on nonbreeding species is especially poor. In this study, aerial surveys were conducted using a small aircraft to cover almost all the coastal areas of Japan. Surveys were conducted from December 2018 to December 2019. More than 262,000 individuals comprising 49 species were recorded. Many seabirds were distributed in the study area, especially in several offshore regions, such as eastern and southern Hokkaido and northern and central Honshu islands, while numbers were limited offshore along the Kii Peninsula, central Honshu, and Shikoku islands. This study is the first case in Japan in which a comprehensive survey of coastal areas was conducted using a unified methodology, and the results are useful for environmental impact assessments of offshore wind farms and the conservation of seabirds.