Bull. Jpn. Soc. Fish. Oceanogr. 78(4), Page 259-267, 2014   Spatial and temporal dynamics of coastal sea surface temperature and catches of Japanese scallop Mizuhopecten yessoensis in Hokkaido Ryota Shibano1†, Masahiko Fujii1, Yasuhiro Yamanaka1, Hiroya Yamano2 and Shintaro Takao1 1 Faculty of Environmental Earth Science, Hokkaido University, N10W5, Sapporo, Hokkaido 060-0810, Japan 2 Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan † E-mail: rshibano@ees.hokudai.ac.jp Climate change such as global warming affects marine ecosystems and fishery resources. The impacts to the species living in coastal regions are considered to become more serious due to a narrow range of inhabitation. Japanese scallop Mizuhopecten yessensis is an important species for Japanese fishery resources as it only lives in coastal regions, especially in Hokkaido. We estimated the dependency of the Japanese scallop on the sea surface temperature dependency (SST) in summer using the foreshore SST and Japanese scallop catch in Hokkaido observations. We also looked at the possible impact of global warming on Japanese scallop using a simplified index for suitable habitats for Japanese scallops and SST obtained by climate models in scenarios with varied CO2 emission. Japanese scallops and relevant industries are projected to be at risk from SST rising in the future around the Sea of Japan and Funka Bay in Hokkaido based on a scenario with intermediate CO2 emission (RCP 4.5 scenario). We propose a simple estimation method applicable to many situations and the importance of observed data in coastal regions. Key words: Japanese scallops, global warming, temperature, observation, future projection, Hokkaido