Ecological consequences of variation in standard metabolism and dominance among salmon parr

Standard metabolic rate (SMR, closely related to basal and resting metabolism) varies by up to threefold among juvenile Atlantic salmon, Salmo salar L., of similar size at common temperature. Here, consequences of this variation are predicted by combining empirically derived relationships between SMR, specific dynamic action, energy budgets, water velocity, food level in the environment and food availability to fish. The range of velocities across which growth is predicted to occur is inversely related to a fish's SMR. Growth is positively related to SMR at high but negatively related to it at low-food levels. The relationship between food level and the range of velocities over which lower SMR fish can grow but higher SMR fish cannot is asymmetrically bi-phasic and peaked. It is predicted that maternal manipulation of offspring SMR would generate fitness benefits through bet-hedging against unpredictability in food level and increases in the overall range of velocities that the family of offspring can occupy and thrive i