Fig. 4. Comparison of pectoral fin and tail function and their contribution to angular velocity at three sizes representative of the larval, juvenile and adult stages. Fin velocities in all three graphs are relative to body velocity (Fig. 1). Thus negative velocities indicate that the fin is moving slower than the body. (A) In the larval individual (FL=0.38 cm) the pectoral fins are moving more slowly than the body. The caudal fin, in contrast, is moving faster than the body and reaches its maximum linear velocity at the same time that maximum angular head velocity is reached. (B) In juvenile fish (FL=0.99 cm) the pectoral and caudal fins are all moving faster than the body around the time of maximum angular head velocity, suggesting that the generation of turning momentum is created by the interaction of both fin types. The caudal fin remains active longer than the pectoral fins that attain a speed close to body speed after 0.05 s, suggesting that the caudal fin is engaged in angular control later in the turn cycle as well. (C) In the adult (FL=1.65 cm) the fin opposite to the direction of turning is moving faster before maximum head angular velocity although the kinematic profile of adults showed very high variation.