Fig. 6. Representative record of heat flux, heart rate and respiration for the dorsal fin in air (FB 109). The diamonds represent respiratory events. Vertical lines are added to the beginning of the data record at each respiratory event to aid in the visual alignment of synchronous records. The heart rate data have been smoothed with a spline (=100, r²=0.49) (JMP IN) to simplify visualization. C_on, a position at the center of the fin directly over a superficial vein; D_on, a position at the distal tip of the fin directly over a superficial vein; C_off, a position at the center of the fin away from superficial veins.