Time to hatch and larval size in relation to temperature and egg size in Atlantic cod (Gadus morhua)

We report on the effect of temperature and egg diameter on the development rates of Atlantic cod (Gadus morhua) eggs and yolk-sac larvae from experiments in which individuals were followed from fertilization until death. Temperature was the only variable to consistently and significantly affect development rates. Egg size had no consistent effect on transition times during the egg phase, but there was a significant increase in the time to yolk absorption as well as the time until death with increasing egg diameter. Larval length at hatch was significantly greater in larger eggs, but only a small proportion of the variance in length at hatch was explained by egg size (6%). Increasing temperature resulted in a significant increase in the size at hatch and may reflect the overall metabolic load placed on the embryo as temperatures decrease below 1-2 degrees C.