Survival of Penaeus monodon postlarvae and juveniles at different salinityand temperature levels

Penaeus monodon postlarvae (PL1, PL5, PL10, and PL15) and juveniles (0.2 an d 2 g mean weights) were acclimated gradually within 6 h to test temperatur es of 22 degrees, 28 degrees, and 33 degrees C. after 24 h, the postlarvae were abruptly transferred to salinity levels of 8, 16, 24, 32, 40, or 50 pp t, and juveniles to 0, 4, 8, 16, 20, 24, 28, 32, 40, 50, or 60 ppt, All tes t animals were previously reared in 32 ppt sea water at a temperature of 27 -29 degrees C. Survival rates were compared after four days for PL1, PL5, a nd PL 10, and 10 days for PL 15. Tests for juveniles lasted seven days. Len gth and total (TPI) or mean (MSI) population stage indices were compared fo r postlarvae. Survival rates of postlarvae and juveniles were generally lower at 33 degre es C. Length and MSI of postlarvae were higher at 33 degrees C than at 22 d egrees C. TPI at PL10 and PL15 were not significantly affected by salinity. Optimal salinity ranges for postlarvae and juveniles were identified based on the different parameters measured.