Fig. 7. Plots of body angle versus (A) tail angle, (B) jet angle and (C) ring axis angle in Triakis semifasciata. The solid lines indicate a significant linear regression, while the dotted lines represent the predicted relationships (see text for discussion). The lack of significance of the tail versus body angle regression (P=0.731, r²=0.003) indicates that the sharks are not altering their tail angle as body angle changes, but instead are maintaining a constant angular relationship regardless of locomotor behavior. Jet angle decreases with increasing body angle (y=-17-1.087x; P<0.001, r²=0.312) at the same rate as the predicted parallel relationship, indicating that the vortex jet is generated at a constant angle to the body regardless of body position. Ring axis angle increases with body angle at the same rate as the predicted perpendicular relationship (y=107+1.280x; P<0.001, r²=0.401). Circles, triangles and squares represent holding, rising and sinking, respectively.