RATES OF WATER TURNOVER AND ENERGY-EXPENDITURE OF FREE-LIVING MALE COMMON SEALS (PHOCA-VITULINA)

The water and energy metabolism of free-living male common seals (Phoca vitulina) during the mating season was investigated using labelled water methods. All three seals, which were captured on two occasions, were in negative energy balance during the study. The daily energy expenditure of one animal, estimated using doubly-labelled water was 52.5 MJ. This is equivalent to six times the basal metabolic rate predicted from Kleiber's (1975) allometric equation. Rates of water turnover were slightly lower than predicted from the allometric equation of Richmond, Langham & Trujillo (1962). The observed rates of water turnover and energy expenditure are considerably higher than those of seals which fast during the mating season, and are consistent with the observed differences in behaviour between males of the common seal and other pinniped males during mating.