Burst Swimming Speed of Japanese Minami Medaka (Oryzias latipes)

Abstract

The authors conducted experiments to investigate the burst swimming speed of the Japanese fish minami medaka (Oryzias latipes) for designing canals and fishways in paddy fields in consideration of the ecosystem. The following results were obtained in the range of body lengths from 2.0 to 2.9 cm; 1) the burst swimming speed of the minami medaka was found to be 33 cm・s^-1 (velocity of pipe flow, 17 cm・s^-1) to 58 cm・s^-1 (velocity of pipe flow, 32 cm・s^-1); their burst swimming speed was 14-24 times their mean body length per second. 2) The minami medaka repeated this instantaneous swimming speed, advancing by approximately 5 cm at a time; the mean of the instantaneous swimming speed was about the same at 1.03 times of the burst swimming speed upon entering the burst swimming section. 3) Under the pipe velocity from 20 to 30 cm・s^-1, more than 65% of the individuals swam distances of 30 cm.