Dj. Martinrobichaud et al., DIRECT FEMINIZATION OF LUMPFISH (CYCLOPTERUS-LUMPUS L) USING 17-BETA-ESTRADIOL-ENRICHED ARTEMIA AS FOOD, Aquaculture, 123(1-2), 1994, pp. 137-151
Artemia nauplii cultured in lipid-enriched media containing 0, 5, 10 o
r 20 mg 17beta-oestradiol/l for 24 h.contained 0, 140, 90 and 231 ng 1
7beta-oestradiol/mg dry wt., respectively. Feminization of lumpfish la
rvae was essentially 100% when the larvae were fed Artemia containing
231-407 ng 17beta-oestradiol/mg dry wt. at first feeding for 20 days.
Immersing eggs or newly hatched larvae at 22, 29 and 36 days post-fert
ilization in 200 mug 17beta-oestradiol/l for 2 h resulted in 68% and 4
6% females in duplicate treatments. The ovaries of some fish which con
sumed Artemia containing 17beta-oestradiol were smaller, filiform and
less developed than those from similar size control females although n
o spermatogenic tissue was detected in these filiform ovaries. This ma
y indicate that females with filiform ovaries were feminized, genotypi
c males. It appears that direct sex-reversal techniques, based upon st
eroid-supplemented Artemia nauplii, has promise of producing monosex p
opulations in fish larvae requiring a diet of live prey during the per
iod of sex determination.