Movie 3.

(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 behind (yz plane). Regions of local instantaneous maximum rates of deformation up to 10 s^-1 are significantly smaller compared to downstream of the filter shown in subplot a in supplementary video 4. The instantaneous maximum rate of deformation is low on either side of the barnacle during the recovery stroke as water is being replenished on front of the cirral fan. (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, and the color scaling is the same as in subplot a un supplementary video 4.