Effects of salinity on egg development and hatching in grey mullet Mugil cephalus L

Grey mullet, Mugil cephalus, collected from ponds were induced to spawn with carp pituitary homogenate and human chorionic gonadotropin (HCG) at 30%o salinity and 26° C. The spontaneously spawned and fertilized eggs were transferred to sea water of different salinities in the range of 5–70%o, either at the 2‐blastomere or the gastrula stage. Those eggs transferred at the gastrula stage were more tolerant to the salinity change than were those transferred at the 2‐blastomere stage. The eggs did develop to the embryonic stage within the salinity range from 5 to 60%o. Hatching occurred in all salinities between 10 and 55%o. However, no larvae survived at 10 or at 55%o. The optimal salinity range for eggs incubating at 22.0–25.5° C was from 30 to 40%o salinity, with the peak at 35%o.