MATERIALS AND METHODS
Trials were conducted at Kamogawa Sea World, Chiba Prefecture, Japan, in May 2010 and June 2011. The aquarium in which experiments were conducted was a semicircular column (depth × length × width = 7.5 × 5 × 10 m; 535 m3). Ten flying fish Cheilopogon heterurus doederleini (mean ± SD fork length: 32.5 ± 1.1 cm; mean body mass: 227.4 ± 18.9 g) and 3 flying fish (fork length: 27.2 ± 2.0 cm; mean body mass 201.3 ± 32.4 g) were captured by commercial fishers with net in Kamogawa, Chiba Prefecture, Japan, in 2010 and 2011, respectively. The fishes were equipped with cylindrical acceleration data loggers (ORI400D3GT: 12mm diameter, 45 mm length, 9 g in air; Little Leonardo Co.) capable of recording 3-dimensional axis acceleration (sway, surge and heave, corresponding