Trophic Requirements of the Sea Urchin Paracentrotus lividus Varies at Different Life Stages: Comprehension of Species Ecology and Implications for Effective Feeding Formulations

Abstract

Investigations on trophic requirements of different life cycle stages of Paracentrotus lividus are crucial for the comprehension of species ecology and for its artificial rearing. The future success of echinoculture depends heavily on the development of suitable and cost-effective diets that are specifically designed to maximize somatic growth during the early life stages and gonadal production in the later stages. In this context, a considerable number of studies have recommended animal sources as supplements in sea urchin diets. However, with the exception of Fernandez and Boudouresque (2000), no studies have investigated the dietary requirements over the different life stages of the sea urchin. In the present study, the growth and nutrition of three life stages of P. lividus (juveniles: 15-25 mm; subadults: 25-35 mm; adults: 45-55 mm) were analyzed over a 4-month rearing experiment. Three experimental diets, with 0%, 20% and 40% of animal sourced enrichments, were tested in parallel in sea urchin three size classes. The food conversion ratio, somatic and gonadal growth were assessed in each condition in order to evaluate the optimal level of animal-sourced supplements for each life stage. A general growth model covering the full post-metamorphic P. lividus life cycle was defined for each condition. During the juvenile stage P. lividus requires higher animal supply (40%), while a feeding requirement shift takes place toward lower animal supply (20%) in sub-adult and adult stages. Our results evidenced that the progressive increase in size after the metamorphosis led to a consequent variation of trophic requirements and food energy allocation in the sea urchin P. lividus. Macronutrient requirements varied widely during the different life stages, in response to changes in the energy allocation from somatic growth to reproductive investment. This study sheds light on P. lividus trophic ecology, broadening our basic knowledge of the dietary requirements of juveniles, sub-adults and adults as a function of their behavior also in the natural environment.

Population status, distribution and trophic implications of Pinna nobilis along the South-eastern Italian coast

“…The pattern from this study led us to hypothesize that a trophic link with the seagrass detritus food-chain may explain both the macroscale-mesoscale association with seagrass species and the microscale crossboundary distribution. In fact, seagrass detritus is highly refractory, since it is largely exported to the nearby areas where it can represent the major food source for other invertebrates [32][33][34] . This hypothesis is consistent with the stomach contents observations reported by Davenport et al 3 indicating detritus as the bulk component, accounting for 95% of the total ingested material.…”

Raking: an innovative and sustainable echinoculture method to produce “caviar” without sacrificing sea urchins

“…In fact, this method allows the production of a healthy luxury seafood from a low-trophic species, whose low ecological impact aquaculture is desirable to prompt culture diversi cation, especially in industrialized countries where the majority of production is based on high-trophic level species. Another important advantage of sea urchin culture is the reduction of water pollution from nitrogenous compounds, since the amount of animal protein supply required by this form of aquaculture is very low 7 . On this point, future research into new sustainable, well-performing and cost-effective diets remains crucial 28,47 .…”

Echinoderm Larvae as Bioindicators for the Assessment of Marine Pollution: Sea Urchin and Sea Cucumber Responsiveness and Future Perspectives

“…indicators due to their extensive distribution, meroplanktonic development, rapid response and the high sensitivity of their planktonic larvae to a large range of contaminates (Sugni et al, 2007). Among echinoderms, sea urchins are a keystone species in hard bottom habitats, controlling the vegetal community dynamics (Grosso et al, 2021(Grosso et al, , 2022, and worldwide are considered an ideal tool for marine eco-toxicological tests since their embryos are sensitive to the adverse effects of a huge range of contaminates, including trace metals, organic compounds, microplastics, bioplastics, nanoparticles, pharmaceuticals, sunscreen products, in addition to complex environmental matrices such as marine waters and sediments (see Pagano et al, 2017aPagano et al, , 2017bGambardella et al, 2021 for a review). Various methodologies were used in the research, exposing sea urchin embryos to increasingly high concentrations of single contaminants in dose-response experiments, as well as a number of environmental stressors, to evaluate both developmental anomalies and biomarker response at molecular level (Chiarelli et al, 2021;Gambardella et al, 2021).…”