Figure 4.

Heart rate (beats per minute) of C. maenas. (A): control crabs, held at 12 °C, and (B): experimental crabs, held at 2 °C. These data are displayed for each 24-h period over 6 days. Whiskers represent 95% confidence limits, boxes show upper and lower quartiles, horizontal bar presents median values, black circles denote outlying values and grey triangles denote mean. * denotes where heart rate is significantly different from that at control temperature. Lowercase letters (above each bar) denote significant differences within treatment groups, like letters are not significantly different from one another.