Allometric growth and condition factor of Atlantic cod (Gadus morhua) fed to satiation: effects of temperature and body weight

The effect of thermal environment on condition factor was examined for six different size-classes of Atlantic cod Gadus morhua fed to satiation. A weight–length relationship for 8 to 1303 g fish reared at 4–20°C indicated an allometric growth (W = aLb, a = 0.0045, b = 3.257) of cod. Changes in relative condition factor (Krel) with temperature were described with a second order polynomial. The most pronounced effect of temperature on body condition was found in the smallest size-classes, but the curves flattened with increased size. Temperature had size-dependent effects on the relative condition factor obtained from an overall weight–length relationship for all fish in the experiment, i.e. Krel increased with weight at 4°C, but decreased with weight at 16 and 20°C. Krel remained high for most size-classes at 8 and 12°C. The slopes (b-values) of the weight–length relationships decreased linearly with temperatures from 4 to 16°C.