The various stages of trochus culture are now defined so that the nomenclature used here is clearly understood. These stages are as follows:
Spawning: Release of gametes (eggs and sperm) by mature trochus held in tanks for that purpose.
Hatchery phase: The period of larval development between fertilization of the egg, through the trochophore larval stage to the veliger larval stage and settlement to the bottom of the tank.
Nursery phase No. 1: The period between larval settlement and growth to about 3 mm diameter.
Nursery phase No. 2: The period between Nursery Phase No. 1 and growth to a size suitable for outplanting on the reef. A suitable size is that at which mortality after outplanting is greatly reduced. This will probably be in the range 10–30 mm diameter.
Ocean nursery phase: The period immediately after outplanting to the reef. Protective structures (cages or artificial habitat) are provided to reduce early mortality from predation, and to allow acclimation to the new environment. This phase is considered further in Section 6.3 and Appendix I.
Ranching: The period between the ocean nursery phase and harvesting at commercial size.
Outplanting and re-seeding are synonymous terms, and refer to the transfer of juvenile trochus from the No. 2 Nursery to juvenile habitat on the reef.
These phases are described in more detail in Section 5 and Appendix I.
