THE INDUCED SPAWNING OF THE GILTHEAD BREAM SPARUS AURATA AND THE REARING OF ITS LARVAE.

THE INDUCED SPAWNING OF THE GILTHEAD BREAM
SPARUS AURATA AND THE REARING OF ITS LARVAE.
M. I. ZAKI AND S. H. ABDEL-RAHMAN.
Institute of Oceanography and Fisheries. Kayet Bey. Alexandria.
ABSTRACf
The gi Ithead bream. Sparus aurata (L.). is one of the
important cultured fish in Egypt. Recently. the catch of
fingerlings from natural water has been dechined and a
shortage of supply resulted. A prograll1lle to produce
fingerlings by artificial propagation was started in 1981
at Alexandria Institute of Oceanography and Fisheries.
Significant success was aChieved and gilthead bream could
be induced to spawn by injection of human chorionic
gonadotropin (HCG). Females caught before the breeding season
(October). requi red about 11000 1. U. HCG. but those caught
duri ng the breedi ng season (December) requ i red about 7500
I.U. HCG to release ripe eggs. Gonadotlopine requirement
for spermati on (i n October about 6000) and about 2000 I. U.
during breeding season (late December and beginning of
January). Dose for spermation was less than that for
ovulation but in the same manner.
Cu ltures of the ha tched Ia rvae were attempted in both
running water and stagnant water systems. SurVival in running
water system with gentle water flow was found to be lower
4th than tha tin the other system. On the day. the larvae
started to feed on roti fers. Hence the rotifer. Brachionus
plicatilus was cultured simultaneously on Chlorilla sp.
and baker’s yeast for feeding the larvae. On the 10th day.
larvae were fed on Artearia nauplii. and from the 15th day
onward they started to accept artificial powdered feeds.