Sexual maturity and hermaphroditism of the red porgy Pagrus pagrus (Teleostei : Sparidae)

Gonadal changes related to sexual maturity were examined by histology in re ared populations of the red porgy Pagrus pagrus L., aged 0.5 to 6.5 years. More than 50% of red porgies were mature at the age of 4 years although som e individuals were already mature at the age of 3, as indicated by changes in the gonadosomatic index, plasma levels of vitellogenin, 17 beta-estradio l and testosterone in females and males. Sex frequency distribution analysi s in relation to the age and histological analysis of the gonads indicated the presence of males originated from the sex change of adult functional fe males. P. pagrus is a protogynous species. Some females had not changed sex up to the age of 6.5 years.