Toxic effects of Ostreopsis ovata on larvae and juveniles of Paracentrotus lividus

► Paracentrotus lividus larvae and juveniles tested for toxicity effects of Ostreopsis ovata. ► Juveniles turned out to be more sensitive than their larvae. ► Timeliness of O. ovata blooms and urchin juvenile occurrence. ► Threaten for Mediterranean P. lividus populations, already under depletion.