Oxygen uptake and heart rate in young Green turtles (Chelonia mydas)



Oxygen uptake. heart rate and breathing frequencies were monitored in yearling Green turtles. Routine fed animals used about 100μ O2 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.