Assessment and future prediction of climate change impacts on the macroalgal bed ecosystem and cultivation in the Seto Inland Sea

• Published in: Suisan Kenkyu Kyoiku Kiko Kenkyu Hokoku no. 49; pp. 27 - 34
• Main Authors: Yoshida, Goro, Shimabukuro, Hiromori, Kiyomoto, Setuo, Kadota, Tatsuru, Yoshimura, Taku, Murase, Noboru, Noda, Mikio, Takenaka, Shoichi, Kono, Yoshimi, Tamura, Toshiharu, Tanada, Norio, Yu, Xiaojie, Yoshie, Naoki, Guo, Xinyu
• Format: Journal Article
• Language: English
• Published: Yokohama Suisan Sougou Kenkyuu Senta Fisheries Research Agency 01.02.2019
• Subjects: Algal mats; Climate change; Ecosystems; Forecasting; Marine; Microalgae culture; Water temperature; INW, Japan Inland Sea
• ISSN: 2432-2830

Macroalgal bed ecosystems are an important platform for coastal biological production and fisheries. After the late 1990s, rapid decline or disappearance of macroalgal beds, generally called Iso-yake, has been spreading along the coast of western Japan where there is an influence of warm ocean currents. This phenomenon has been occurring with an increasing trend in water temperature in recent decades and is considered to be an impact of the climate change. The Seto Inland Sea is the largest semi-enclosed sea area in Japan, and macroalgal beds in the area are still intact with no prominent sign of Iso-yake. However, water temperature in the Seto Inland Sea has also been increasing for a few decades, and according to climate change scenarios, negative impacts to macroalgal beds and their ecological functions are possible in the future in the area. Against this background of concern, we conducted research on the assessment and future prediction of climate change impacts on the macroalgal bed ecosystem in the Seto Inland Sea and associated sea areas. The research consisted of 1) field monitoring of macroalgal beds and associated spatio-temporal variation in water temperature, including along the coast of Kyushu (Nagasaki) where loss or changes of macroalgal beds has created a large social problem; 2) experiments on physiology and behavior of key species in macroalgal bed ecosystems (macroalgae and herbivorous fish) with respect to temperature and other conditions to understand the mechanisms of the ecosystem shift; 3) construction of an original physical model to reproduce past temperatures in the environment and predict future ones in the applicable ocean areas; and 4) interpreting the impact of future water temperature conditions predicted by the model on macroalgal beds. In addition, impacts on macroalgal cultivation, which is an important industry in the Seto Inland Sea, were also assessed. In this paper, some of the main results and conclusions are introduced.