Microphotographs (10 × magnifications) of histological slides for five gonadal maturity stages in male yellowfin snapper, Lutjanus xanthopinnis, from eastern South China Sea(Malaysia). (I) Immature phase containing spermatogonia (stage I). (II) Developing/regenerating phase (stage II); (III) Spawning capable phase. (IV) Actively spawning phase containing very high numbers of spermatozoa (stage IV). (V) Regressing phase (stage V). Abbreviations: Sg1 = primary spermatogonia; Sc1 = primary spermatocyte; Sc2 =secondary spermatocyte; St = spermatid; Sz = spermatozoa, Lu = lumen; Scy = spermatocyst.