In order to avoid using immature spawners, the potential female should be selected on the basis of egg size. The stages of maturity for male and female seabass are given in Table 1. Spawning takes place between stage V, the fully ripe condition, and stage VI, the spent. The stage of maturity of the female fish can be examined by means of inserting a polyethylene cannula 1.5 mm in diameter into the oviduct. The oocysts are extracted from the ovaries for examination. Only spawners with stage IV-V oocysts of average diameter of 0.8 mm are selected for induced ovulation.
