Salinity tolerance of fertilized eggs and yolk-sac larvae of the rabbitfish Siganus guttatus (Bloch)

Abstract

Among naturally spawned and hormonally induced eggs of Siganus guttatus, salinity levels, at which at least 90% of the eggs hatched, ranged from 7 to 67 ppt for naturally spawned eggs and from 9 to 67 ppt for hormonally induced eggs. Salinity levels at which naturally spawned eggs yielded at least 50% normal larvae ranged from 7 to 62 ppt; salinity levels providing at least 90% normal larvae ranged from 10 to 51 ppt. Salinity levels at which 50% larvae survived for 12 h after hatching ranged from 10 to 45 ppt, and for 24 h after hatching, from 14 to 37 ppt. From the results, it is recommended that the incubation salinity of S. guttatus be within the range 10–51 ppt, and for yolk-sac larval maintenance, within the range 14–37 ppt.