Finfish Breeding and Hatchery Management (2+1)

Unit 14 - Breeding of groupers

14.2. Breeding of E. tauvina

• For induced breeding, specimens obtained from fishermen are maintained in RCC tanks on a deiet of frozen/fresh trash fish at 5% b.w. daily.
• Since E. tauvina is a protogynous hermaphrodite, females when they reach 650-700 g, change to male.Therefore, natural males are difficult to get.
• For induced breeding, female groupersare artificially transformed to sexual males by male hormone 17α –methyltestosterone (17 α –MT).
• Oral administration of 17 α –MT at 1 mg/kg b.w. given 3 times a week for 2 months is effective.
• Natural females and sex-reversed males have to be maintained separately.
• Spermiation occurs within 4 months and lasts for at least 4 months after implantation.
• Females with egg diameter of 0.4 mm are selected and injected with 2 doses of HCG at 250 IU/kg and a third injection of HCG at 100 IU/kg + salmon pituitary extract at 10 mg/kg at one day interval.
• Full maturation occurs 52-54 hours after injection.
• Fertilization is carried out artificially using dry method.
• Eggs hatch after 24 hours at 27-30^oC.