Induced sex change, spawning
and larviculture of potato grouper, Epinephelus tukula
Shinn-Lih Yeh, Quen-Chai Dai, Yeong-Torng Chu,
Ching-Ming Kuo, Yun-Yuan Ting, Ching-Fong Chang-2003
Aquaculture, 228(1-4): 371-381
Abstract:
The potato grouper (Epinephelus tukula) is a
new aquaculture species with high economic potential. This is the first
report of induced sex change, reproduction and larval rearing in this
species. The smallest body size at which mature females were observed was 90
cm in total length and 16 kg in body weight. The diameter of tertiary yolk
globule stage of oocytes was 505±10 µm for 16–24 kg individuals. Larger
oocytes (552±13 µm) were obtained from individuals at 24 kg body weight.
Implantation with an androgen mixture (1000 µg/kg body weight) containing
testosterone, 17α-methyltestosterone, and testosterone propionate in
equal ratios, was applied to female groupers for the induction of sex change
in March. Sex change had occurred by 30 days after androgen implantation,
and the male ratio reached 66.7% by day 70. Natural mating and spawning
activity were found in females and sex-changed males in April. The
fertilized eggs were hatched and reared successfully with a series of live
foods. Metamorphosis occurred and larvae became juveniles with spots and
skin pigmentation by 29.3 mm body length, with complete reduction in the
pelvic and dorsal fins by 33 days after hatch.
(Department of Aquaculture, National Taiwan Ocean
University, Keelung 202, Taiwan, ROC, e-mail of Ching-Fong Chang: b0044@mail.ntou.edu.tw)