Wild dusky grouper were reared from 1998 to 2000 under different regimes of temperature and separated into social units with different female/male ratio. Sex and reproductive condition of fish were monitored throughout ovarian biopsies and by RIAs of sex steroids over three reproductive cycles. The social conditioning applied to breeders induced spontaneous sex change. Four specimens underwent sex inversion within 12-48 months, producing motile and fertile sperm. Sex change was observed in polygynic groups in which non males had been included. The control of seawater temperature regime, together with social control, reduced reproductive dysfunction in sexually mature females and enhanced the first sexual maturity in puberal females.
Effects of environmental and social factors on sexual maturity and sex inversion in captive dusky grouper Epinephelus marginatus.
MASSARI, ALESSANDRA;BOTTERO, SERGIO;MANDICH, ALBERTA
2003-01-01
Abstract
Wild dusky grouper were reared from 1998 to 2000 under different regimes of temperature and separated into social units with different female/male ratio. Sex and reproductive condition of fish were monitored throughout ovarian biopsies and by RIAs of sex steroids over three reproductive cycles. The social conditioning applied to breeders induced spontaneous sex change. Four specimens underwent sex inversion within 12-48 months, producing motile and fertile sperm. Sex change was observed in polygynic groups in which non males had been included. The control of seawater temperature regime, together with social control, reduced reproductive dysfunction in sexually mature females and enhanced the first sexual maturity in puberal females.
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