Variations in energy contents of liver and musculature of immature pollock (Pollachius virens) were analyzed by bomb calorimetry and then correlated to the liver index (liver weight as a percentage of body weight). For fish weighing between 400 and 1500 g, relationships between energy contents of liver and musculature and the liver index were described by mathematical functions. The mean energy content of other fish tissues, excluding liver, musculature, and gonads was constant. The total energy content of an immature pollock can thus be determined. The same relationships should be adaptable to other species that store their primary fat reserves in the liver. Key words: Pollachius virens, liver index, energy content