Can sea urchins benefit from an artificial diet? Physiological and histological assessment for echinoculture feasibility evaluation

In the Mediterranean sea, since the time of ancient Greece, the sea urchin Paracentrotus lividus has been considered a delicacy, and as a consequence, the market demand has increased since the early 1970s, significantly causing a depletion of wild stock. For this reason, the interest in breeding sea urchins has widened over the last two decades and several formulated diets were developed. In order to identify a low-cost diet, which is able to promote both the maintenance and the gonadal growth of organisms in recirculating aquaculture system (RAS), we evaluated the food intake of three different diets: the first composed of macroalgae naturally present in the sea urchins collection site, a second diet based on maize and spinach and finally a diet based on pellet normally used in aquaculture. The results presented in this study demonstrated the good feasibility of a low-cost and easy-to-standardize diet, such as that based on maize and spinach, in rearing vulnerable species such as P.lividus in RAS.