PLASTICITY OF GONAD DEVELOPMENT IN HERMAPHRODITIC SPARIDS - OVOTESTISONTOGENY IN A PROTANDRIC SPECIES, LITHOGNATHUS-MORMYRUS

Heterosexual gonad development in a sparid species, Lithognathus mormy rus, was studied by histological and cytological examination, during t he first three years of life. Gonad bisexuality is achieved after two months of development, according to the cytological dynamics known in sparids. In one-year-old fishes, a variability in the gonad morphology of the juvenile ovotestis is shown: three different types of ovotesti s have been identified within the same cohort: ovotestes with testicul ar prevalence (25%), testicular and ovarian equivalence (20%), and ova rian prevalence (55%). This morphological variability of the juvenile ovotestes was consistent with the histocytological analysis of the sex ual structure of the adult stock at the first sexual maturity, which c onstituted 55.5% of functional males (stemming from the first two type s of ovotestis) and 44.5% of primary females (from the third type). Th e plasticity of sexual expression in sparids is emphasized, revealing the potentialities of the ovotestis.