Activity, milk intake and energy consumption in free-living ringed seal (Phoca hispida) pups

Measurements of growth, activity and energy consumption and estimates of milk intake were made in free-living, nursing ringed seal (Phoca hispida) pups. This was accomplished through the simultaneous use of time-depth recorders and the doubly labelled water technique. The pups spent an average of 52 +/- 7% of their time hauled out on the ice, 37 +/- 5% of the time in the water at the surface, and 11 +/- 5% of the time diving. Average daily mass gain of the pups (n=3) throughout the duration of the study period was 0.35 +/- 0.08 kg. The composition of the mass gain was 76% fat, 6% protein, and 18% water. The total water flux was measured to be 52 +/- 10 ml.kg-1.day-1. Average CO2 production was 0.85 +/- 0.16 ml.g-1.h-1, corresponding to a field metabolic rate of 0.55 +/- 0.10 MJ.kg-1.day-1, or 3.8 +/- 0.6 times the predicted basal metabolic rate based on body size (Kleiber 1975). Average daily milk intake was estimated to be 1379 +/- 390 ml. The field metabolic rate for the different components of seal pup activity budgets were calculated to be FMRhaul out = 1.34 BMR, FMRsurface = 6.44 BMR, and FMRdiving = 5.88 BMR.