ABSTRACT
Variation in egg size within a population of young sea urchins was investigated by studies on larval development and biochemical composition of eggs and larvae. Eggs from Paracentrotus lividus reared in the laboratory from fertilization up to 2.5 years were used in the experiments. Eggs were screened into <60pm and >60pm. Those <60pm were richer in protein and lipid than those >60pm. Larvae from these small eggs had higher organic content than larvae from large eggs, although developmental rates and the size at metamorphosis did not differ. The advantages of small and large eggs in relation with environmental conditions were discussed. Egg quality did not differ between young adult sea urchins reared in the laboratory with a monospecific diet (adult diameter=21-25mm) and adults collected from the field with a plurispecific diet (adult diameter=45-55mm).
