The effect of reduced salinity on growth, food conversion and protein efficiency ratio in juvenile spotted grunter, Pomadasys commersonnii (Lacepede)(Teleostei : Haemulidae)

Salinity has been proven to have a significant effect on the growth and sur vival of anadromous fish species; however, there is a paucity of informatio n regarding its effect on euryhaline marine species. Experiments were condu cted to examine the effect of hyposalinity on the osmoregulation and growth of juvenile spotted grunter, Pomadasys commersonnii (Lacepede). Although t he spotted grunter is considered to be a strong osmoregulator, growth perfo rmance and survival was compromised below isosmotic concentrations. The gro wth rate, condition and food conversion of fish in low salinity (5%) were l ower than in either isosmotic (12%) or hyperosmotic (25% and 35%) condition s. Mortality was also significantly higher at 5%, From these results, it is concluded that P, commersonnii can be successfully cultured in salinities ranging from 12% to full-strength sea water (35%).