Induced Spawning of Striped Mullet by Hormone Injection

抄録

Preliminary results obtained from a series of experiments conducted during the striped mullet (Mugil cephalus LINNAEUS) fishing season of 1963 indicated that the ripe striped mullets during their spawning migration to the southwestern coast of Taiwan could be induced to spawn by injection of hormonal materials.
The threshold dosage for precipitating ovulation of the female mullets was approximately at the level of 2.0 pituitaries taken from fish of the same species and of comparable size combined with 40 rabbit units of Synahorin (a gonadotropic product composed of a mixture of chorionic gonadotropin and hypophysial extract). The great majority of the males, however, did not require administration of hormones, to furnish sperms for the ovulated eggs.
The embryonic development of this species observed from the external features is described and shown in photomicrographs of living specimens in this paper. The hatching of these eggs took place in 59 to 64 hours at water temperatures ranging from 20.0° to 24.0°C.
Most of the newly hatched larvae died two days after hatching, and none of them survived beyond the prelarval stage when reared either in aquaria or holding boxes in shallow sea.