The effect of extrinsic and intrinsic factors on oxygen consumption by the southern rock lobster, Jasus edwardsii.

The oxygen consumption rate of the southern rock lobster, Jasus edwardsii, was evaluated in response to body weight, temperature, activity, handling, diurnal rhythm, feeding and oxygen saturation level. There was a positive relationship between standard oxygen consumption (M(O(2))) and both body weight and water temperature. The relationship between total oxygen consumption and wet whole body weight was described by the equation: LogM(O(2))=0.595log W-0.396 (r(2)=0.83). The relationship between weight-specific oxygen consumption and temperature was described by the equation: LogM(O(2))=0.047T-2.25 (r(2)=0.94). Activity had a significant influence on the oxygen consumption rate, causing a three-fold increase above the standard rate at the temperature of acclimation (13 degrees C). However, at temperatures approaching the upper and lower extremes, lobsters had a decreased ability to increase their oxygen consumption rates during activity. Lobsters took 4.5-5 h to return to standard oxygen consumption rates after a period of emersion and handling. A strong diurnal rhythm to oxygen consumption was recorded. J. edwardsii displayed a classic postprandial increase in oxygen consumption. A peak (1.72 times standard M(O(2))) occurred 10-13 h after feeding with an increase above standard M(O(2)) being maintained for 42 h. In its rested state J. edwardsii was an oxygen regulator down to a critical oxygen tension of 58 Torr, whilst activity resulted in the critical oxygen tension increasing to 93 Torr.