REPRODUCTIVE-CYCLE AND SEX INVERSION OF THE SEA-BASS, LATES-CALCARIFER, REARED IN SEA CAGES IN FRENCH-POLYNESIA - HISTOLOGICAL AND MORPHOMETRIC DESCRIPTION

The reproductive cycle and sex inversion of the protandrous, tropical seabass, Lates calcarifer, reared in sea-cages in French Polynesia, we re studied. In Tahiti, this species exhibits a single annual reproduct ive period from October to February beginning with the warm and wet se ason. Sex inversion begins at the end of this reproductive period in p ost-spawning males. The main histological features of this process wer e: degeneration of testicular tissue, appearance of peripheral female germinal cells, and centripetal proliferation of ovarian tissue. Compl etion of sex inversion required profound morphological changes in the gonads because of the strong dimorphism that exists between testis and ovary. All transitional gonads appeared morphologically smaller than testes and typically had a red-pink colour. About 45% of the three-yea r-old male stock underwent sex inversion, and males averaged smaller i n size than did females and transitional fish.