METABOLIC RATES OF MINKE WHALES (BALAENOPTERA-ACUTOROSTRATA) IN COLD WATER

Body temperature, blubber thickness and lung capacity (V(c)) were recorded in newly killed minke whales, while respiratory frequency (f) was determined in free-swimming animals. Mean deep (thoracic) body temperature was 34.7 +/- 0.8 (SD)-degrees-C (n = 14). Weighted mean core/blubber interface temperature in animals caught in 2.5-5.5-degrees-C water was 28.8 +/- 1.7-degrees-C (n = 8). The minimum average rate of sensible heat loss (HL(s)) was 3.81 +/- 0.53 (SD) W kg(w)-0.75 (n = 8) in animals with body masses (w) in the range of 1840 to 5740 kg, HL(s) being inversely proportional to w (HL(s) = -2.98 10(-4) w + 4.89 W kg(w)-0.75 (n = 8, r2 = 0.73, P < 0.01)). The average rate of respiratory heat loss (HL(r)) was 0.26 +/- 0.04 (SD) W kg(w)-0.75, regardless of w, in the same 8 animals. Total rates of heat loss (HL = HL(r) + HL(s)) in 2.5-5.5-degrees-C water ranged between 3.40 and 4.87 W kg(w)-0.75 with an average of 4.06 +/- 0.52 (SD) W kg(w)-0.75 (n = 8). Estimates of oxygen consumption based on records of f and V(c), and data on oxygen extraction from other cetaceans, yielded a range of metabolic rates which compared nicely with the calculated HL values.