The effect of body fat on basal metabolic rate in adult harp seals (Phoca groenlandica)

Three adult harp seals (Phoca groenlandica) were fed different daily amount s of capelin (Mallotus villosus), and their body composition determined by use of the tritiated water method at different levels of fattening. Basal m etabolic rate (BMR) was measured after 5 days of fasting by indirect calori metry, and was on average 1.1 W.kg(-1) when 45% of body mass (BM) was fat a nd 2.3 W.kg(-1) when body fat was reduced to 13% of BM. This suggests that body fat contributes little to BMR in these animals. It follows, that predi ctions of BMR on this basis of BM is questionable in seals, in which body f at may change seasonally between 20 and 60% of BM. (C) 1999 Elsevier Scienc e Inc. All rights reserved.