BODY-MASS LOSS, UTILIZATION OF BLUBBER AND FAT, AND ENERGETIC REQUIREMENTS OF MALE SOUTHERN ELEPHANT SEALS, MIROUNGA-LEONINA, DURING THE MOLTING FAST

The energetic requirements of male southern elephant seals, Mirounga leonina, were estimated from mass loss, and changes in blubber mass determined by ultrasound in 11 seals over the moulting fast. Mean rate of mass loss was 9.60+/-2.25 kg day-1 or 6.46+/-0.77 g kg-1 day-1, with about 63% of this lost as fat. Blubber was depleted by about 48% over the moulting period. The relative distribution of blubber remained unchanged after the moult, and seals lost blubber at similar rates over all areas of the body. Energy expenditure was estimated to be 7.54+/-82 MJ kg-1 over the mean 35.6-day moulting period.