Survival and growth of early juveniles of barramundi, Lates calcarifer (Bloch, 1790) in inland saline groundwater ATUL KUMAR JAIN1*, GIRISH KUMAR1 and SUBHASH CHANDRA MUKHERJEE2 1 Aquaculture Research Laboratory (CIFE, Mumbai), Udaipur - 313 001, Rajasthan, India 2 Central Institute of Fisheries Education, Versona, Mumbai - 400 061, India Abstract Survival and growth rate of juveniles (35 days of age) of barramundi Lates calcarifer were studied in inland saline groundwater (ISGW) at 15 and 25‰ salinities for 30 days and were compared with artificial seawater (ASW) at similar salinities. ISGW of 58‰ was drawn from an open well in Western Rajasthan, India. It was diluted to 15 and 25‰ by adding fresh water. Survival and specific growth rate (SGR) of juveniles were 100% and 4.552±0.126 respectively in ISGW at 15‰. It was similar (p>0.05) to survival (100%) and SGR (4.567±0.165) in ASW at 15‰. Survival and SGR became reduced to 80% and 3.938±0.105 in ISGW at 25‰ and that was significantly (p<0.05) lower to that in ISGW at 15‰. The survival and SGR in ASW at 25‰ was 100% and 4.448±0.416 respectively that was much similar to that in ASW at 15‰. The concentration of potassium was 34.2 and 60.8 mg l-1 in ISGW of 15 and 25‰ and 173.8 and 289 mg l-1 respectively in ASW of similar salinities. In ISGW at both 15 and 25‰, K:Cl ratio was 0.003, but it was 0.02 in ASW. Potassium deficiency in ISGW did not affect the survival and growth of early juveniles of L. calcarifer at 15‰, but it was harmful at 25ò. The present study suggests that ISGW at low salinity (15‰) that was deficient in potassium (34.2 mg l-1) could be used for growing early juveniles of L. calcarifer, but it may need potassium supplementation at higher salinities.   < back .