Embryonic and larval development of sea urchin (Temnopleurus reevesii)

In order to develop the artificial breeding technology of Temnopleurus reevesii, and to provide scientific references for its artificial breeding and application, we carried out a series of laboratory procedures including spawning induction, fertilization, incubation and larval rearing. We observed its developmental process from fertilized egg to juvenile, and measured the size of the fertilized eggs, embryos and larvae. The results indicate that T. reevesii could be successfully induced to spawn by injection of 0.5 mol·L⁻¹ KCl solution, and the fertilization rates ranged from 87.4% to 95.7%, with an average of (91.6±2.4)%. Under the conditions including water temperatures of 24–25 ℃ and a larval rearing density of approximately 1 ind·mL⁻¹, the cleavage commenced after 45 min and the morula stage was reached by 3 h and 45 min, the blastula stage was reached by 6 h, the gastrula stage was reached by 12 h, the 2-armed larva stage was reached by 22 h, the 4-armed larva stage was reached by 1 d and 12 h, the 6-armed larva stage was reached by 5 d and 16 h, and the 8-armed larva stage was reached by 9 d. The larvae metamorphosis into juvenile happened around 32 d. Compared with other sea urchin species, T. reevesii developed faster prior to the four-armed larva stage, followed by a slower pace post that stage.