Effect of body mass, temperature and food deprivation on oxygen consumption rate of common cuttlefish Sepia officinalis

Predictions of short and long term changes in Sepia officinalis metabolism are useful, since this species is both economically important for aquaculture and also is an ideal experimental laboratory organism. In this study standard and routine oxygen consumption rates of newly hatched and juvenile laboratory raised cuttlefish S. officinalis ranging between 0.04 and 18.48 g dry body mass (Dm), were measured over a range of temperatures (10, 15, 20 and 25A degrees C). The mass exponent (b) ranged between 0.706 and 0.992 for standard oxygen consumption and between 0.694 and 0.990 for routine oxygen consumption. Oxygen consumption scaled allometrically (b = 0.7) with body mass for cuttlefish < 2 g Dm and isometrically (b = 1) thereafter. No significant differences were apparent amongst the slopes of oxygen consumption and body mass at different temperatures for standard and routine oxygen consumption. However, the intercepts differed significantly amongst the regression lines, indicating a significant effect of temperature on the magnitude of oxygen consumption. The combined effect of temperature (T) and dry body mass (Dm) are best described by the following equations: cuttlefish < 2 g, MO2 = 0.116Dm(0.711)1.086 (T) and > 2 g, MO2 = 0.076Dm(0.983)1.091 (T) for standard oxygen consumption; cuttlefish < 2 g, MO2 = 0.538Dm(0.729)1.057 (T) and > 2 g, MO2 = 0.225Dm(0.962)1.081 (T) for routine oxygen consumption. Using these equations it was estimated that a cuttlefish of 1 g Dm held at 20A degrees C, eating 5% Dm day(-1) and undergoing standard and routine metabolism consumes 21.3 and 35.4%, respectively of its total daily energy intake. Juvenile cuttlefish (3.32-5.08 g Dm) held at 15A degrees C and deprived of food for 27 days maintained a stable standard oxygen consumption rate for the first 6 days following starvation. By the 18th day without food, oxygen consumption rate had declined by 53% and further declined to 65% below the standard oxygen consumption rate on the 27th day. Upon resumption of feeding, the respiration rate returned immediately to the initial level prior to food deprivation. The present study defines the basic energy requirements and general physiological state of young cuttlefish at temperatures of 10-25A degrees C with and without food.