Rearing Sea Urchins to Promote 'Ready-to-Spawn' Conditions for Ecotoxicological Surveys

The sea urchin Paracentrotus lividus is a good model in ecotoxicology, but adults living along the Italian coasts have a limited reproductive period. In this species, natural or human-driven pressures may lead to limited gamete availability for ecotoxicological surveys. This study investigates the quality of early developmental stages of wild and cultured sea urchins to be used in ecotoxicology, avoiding field collection of mature specimens. Adult sea urchins were cultured in the laboratory for 2 years. Every 45 days, fertilization and larval quality were checked and compared to those from adults sampled in the wild. Fertilization was never affected, differently from development, which was impaired in the larvae obtained from sea urchins reared for more than one year. Fertilization and embryotoxicity were performed using copper nitrate in wild and cultured sea urchins. Fertilization did not differ up to ten months, while similar embryotoxicity was only found up to 5 months. This study promotes rearing sea urchins in 'ready-to-spawn' conditions for ecotoxicology surveys by recommending 10- and 5-month rearing times to assess fertilization and embryo toxicity, respectively. Here, we provided a baseline in marine ecotoxicology to obtain gametes on demand, irrespective of reproductive period and other pressures that may impact gamete availability.