Diurnal changes in activity and metabolic rate in<i>octopus vulgaris</i>

Abstract

The activity of Octopus vulgaris was monitored continuously in the laboratory. Starving animals are active mainly at night, with an activity peak at about 23.00 hrs. Feeding in the evening preserves this pattern, while feeding at 10.00 hrs or ad lib disrupts but does not reverse it. Oxygen consumption rises and falls with activity. For a 350g animal, the Standard Metabolic rate is about 53 ml O2 Kg−1 h−1 Routine M.R. 72 ml O2 Kg−1 h−1; feeding and movement both produce large increases in oxygen consumption. Oxygen uptake varies as Weight 0.7 and shows a Q10 of 1.77. These findings are discussed in relation to previous reports of the oxygen consumption of cephalopods, to the diurnal pattern of activity shown by O. vulgaris in the sea, and in relation to the results of training experiments.