Figure 2.
Moving average (A) and average (B) heart rate (fH, bpm) values in free-swimming lumpfish (n = 14) recorded every 4 hours for 5 days following the surgical implantation of the Star-Oddi micro-HRT logger. After 48 hours (dotted line), two lumpfish were transferred to containers inside the tank to be fasted for an additional ~66 hours. (A) Fish were on a 14-hour light:10-hour dark photoperiod (grey bars represent periods of darkness/night-time). (B) Open symbols represent day-time, while dark symbols represent night-time values. Dissimilar lower-case letters indicate a significant difference within a photoperiod group (for night-time values the letters are bolded), while an asterisk represents a significant difference between day-time and night-time values at each measurement point. The symbols represent means ± S.E.M. with each value representing the average of 3 data points per fish. Note: N1 was not included in the analysis.