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Fig. 10. Schematic illustration of laterally directed dorsal fin force (large blue
arrow) generated during steady swimming at 0.5 and 1.0 L
s1 by rainbow trout, the roll and yaw torques (curved blue
arrows) induced by this dorsal fin moment, and the hypothesized counteracting
torques (red arrows) produced by the pectoral and anal fins to achieve a
moment balance during steady locomotion. Asymmetrical movement of the caudal
fin and oscillation of the pelvic fins could also assist in generating
compensatory roll and yaw moments. Although the paired fins are not recruited
continuously by trout during steady swimming
(Drucker and Lauder, 2003),
intermittent excursions of these propulsors may serve to correct moment
imbalances. Steady swimming by trout involves the active use of multiple fins
to maintain body stability in the face of environmental perturbations. CM,
center of mass of the body.