Optimizing somatic growth of the edible sea urchin (Paracentrotus lividus Lmk) (Echinodermata: Echinoidea) in closed-circuit cultivation with artificial diet

The cultivation of sea urchins in closed-circuit offers the opportunity to optimize their growth by controlling the rearing parameters. Yet the question of water pollution by food waste is most critical. Little is known about the requirements of cultivated sea urchins in terms of food composition. The impact of two artificial diets (soybeans and soybeans-fish pellets) versus fresh and dried kelp (the natural food of Paracentrotus lividus) on feeding, digestion and somatic growth has been investigated under semi-intensive cultivation. Total waste production (summing wastes produced at different levels: feeding, digestion and assimilation) has been evaluated for each diet. The two types of artificial diets appear as efficient as fresh kelp for somatic growth, but wastes are reduced by 20% due to a much higher conversion efficiency. These preliminary results suggest that a drastic improvement of feeding strategies in sea urchins cultivation would be obtained soon by using adequate artificial food formulation.