It is interesting to note that sex-changed males produced
using AI treatment were functional males. According
to the histological observations, the testes of the
sex-changed males were filled with large amounts of
sperm, similar to the normal testes of mature males
during the spawning season. The active, sex-changed
males were mated with natural normal females in the
culture tank and yielded fertilized eggs. The fertilization
rate was 53%, which was higher than the natural fertilization
rate of E. merra in the wild (40%; Bhandari et al.,
2005). In the potato grouper, males produced through
androgen treatment show a very low fertilization rate
(20%; Yeh et al., 2003a). We also checked the embryonic
development of fertilized eggs and cultivated
hatchlings to determine the condition of the larvae.
The absence of anatomical deformities among the embryos
and larvae suggests that the fertilized eggs were
good enough to produce quality seed in captivity.