Particle-tracking experiments of the transport of eggs, larvae and juveniles of red tilefish Branchiostegus japonicus from the East China Sea to the coastal area of Miyazaki Prefecture, Japan
2019
Ishikawa, K. (The University of Tokyo, Kashiwa, Chiba (Japan). Atmosphere and Ocean Research Institute) | Itoh, S. | Nakamura, H. | Nishina, A. | Saito, T. | Tokeshi, T.
This study investigated transport processes of red tilefish Branchiostegus japonicus from the East China Sea to the coastal area of Miyazaki Prefecture by particle-tracking experiments. Particles were released from areas along the shelf break of the East China Sea in autumn, which are the main spawning ground and season, respectively, and the movement patterns and paths were examined using reanalysis data of an ocean data assimilation system. After 45 days from the release, which is the average duration until settlement, 0.01-0.7% of particles released in the East China Sea reached the coastal area of Miyazaki Prefecture. Among them, 90% and 10% of particles passed through the Ohsumi and the Tokara Straits, respectively. The number of particles reaching Miyazaki Prefecture was positively correlated with those passing through the Ohsumi Strait, while mass arrival events were further related to the deceleration of the Ohsumi Branch Current caused by a small meander of the Kuroshio. Proportions of particles by destination at Day 45, including those not reaching Miyazaki Prefecture, were 10.8% to the Pacific, 1.5% to the Sea of Japan, and 88% remained within the East China Sea. Therefore, it is likely that red tilefish has a major reproduction cycle within the East China Sea, while larvae and juveniles were also supplied from there to Japanese coastal areas. Finally, it is suggested that the Ohsumi Strait is the main passage of larval/juvenile transport of red tilefish, from the East China Sea to the coastal areas of Miyazaki Prefecture.
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