Changes in Energy Stores during Postnatal Development of the Harp Seal, Phoca groenlandica

Abstract

Postnatal harp seals, collected during the 1979 and 1980 whelping seasons in the Gulf of St. Lawrence, were examined with respect to proximate composition and energy content of psoas muscle, blubber, viscera, and carcass (eviscerated lean body mass). During nursing, blubber stores of pups increased qualitatively as well as quantitatively, with caloric density increasing from 3.7 kcal/g to 8.9 kcal/g by age 9 days. Over the same time period, caloric density of carcass doubled to 2.5 kcal/g, with neutral lipid stores accounting for 12.5% of carcass wet weight. Neutral lipid levels in viscera approached 9% at weaning. These lipid stores in the carcass and viscera represent important energy sources during the subsequent post weaning fast.