(a) Time resolved maximum deformation rate plot showing the maximum deformation rate during the recovery and power stroke of actively feeding B. crenatus in quiescent water. The barnacle is viewed from the side (xz plane). Local instantaneous maximum rates of deformation are up to 10 s-1 and most of the regions with high deformation are located downstream of the barnacle filter. (b) Vector plot overlaid on the images of the barnacle to show the position and movement of the cirri as they relate to the maximum deformation rate fields. The subplots a and b are synchronized and played back at 0.25 x actual speed for easier interpretation.