Bull. Jpn. Soc. Fish. Oceanogr. 76(1), Page 9-17, 2012   Numerical study on the transport process of jellyfish Aurelia aurita sensu lato in Mikawa Bay, Japan Kazuhiro Aoki1 †, Manabu Shimizu1, Hiroshi Kuroda1, Masaya Toyokawa2 and Satoshi Yamada3 1 National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan 2 Seikai National Fisheries Research Institute, 1551-8 Taira, Nagasaki, Nagasaki 851-2213, Japan 3 Aichi Fisheries Research Institute, 97 Wakamiya, Miya, Gamagori, Aichi 443-0021, Japan † e-mail: kazuaoki@affrc.go.jp The transport process of jellyfish (Aurelia aurita sensu lato) in Mikawa Bay in 2008 was studied using a hydrodynamic model and particle tracking method. In the result of the particle tracking experiment, particles concentrate along Atsumi Peninsula and the bay head of the eastern part where dense populations of jellyfish are found by ob- servations in summer. Jellyfish ephyrae located around the bay mouth in winter-spring were transported to the eastern part of the bay in summer. Bottom intrusions affected the jellyfish transporting to the eastern part of the bay. These bottom intrusions occurred during neap tide or eastern wind. Diurnal vertical migration of jellyfish also plays important roles in strandings in the bay. Key words: Aurelia aurita sensu lato, Mikawa Bay, diurnal vertical migration, bottom intrusion, Regional Ocean Modeling Systems