Oxygen uptake and heart rate in young Green turtles <i>(Chelonia mydas)</i>

Abstract

Oxygen uptake. heart rate and breathing frequencies were monitored in yearling Green turtles. Routine fed animals used about 100μ O 2 g live turtle ‐1 h ‐1 at 25d̀C; this value was not significantly affected by size or short term food deprivation. Starved turtle showed a doubling of oxygen uptake after a satiation meal and heightened uptake persisted for five days. Between 15d̀ and 30d̀C oxygen consumption increased with rising temperature; below 15d̀C there was falling temperature. Vigorous activity increased oxygen uptake to two or three times thr routine fed levels. Turtles swimming gently at 25d̀C exhibited a heart rate of around 46–48 beats min ‐1 ; this rose to 64–68 beats min ‐1 during vigorous and continuous activity. Contrary to expectations profound bradycardia was not seen during diving; even during 10 min dives a rate of 25–28 beats min ‐1 was sustained. Significantly lower heart rates were only seen in turtles which were apparently asleep.