author(s)
G Ganesh, B Chamundeswari Devi, DRK Reddy, A Srinivasa Rao, R Ram Mohan, D Pamanna, P Ranjith Kumar and LV Naga Mahesh

abstract
Brackish water fish farming, principally of Barramundi or Asian seabass (Lates calcarifer) and milk fish (Chanos chanos), is more established, being based on hatchery – produced fry and fingerlings. The intensive culture of fish in cages, such as floating net cages is widespread around the world, and is indicated as one of the major methods for intense fish production in the tropics. The Optimum fish production is totally dependent on the physical, chemical and biological qualities of water to most of the extent. Hence, successful cage culture management requires an understanding of water quality. The present study was conducted in the closed bay near Suryalanka, Baptla and Guntur district. By using standard methods (APHA), water quality parameters were measured at 8.00 hrs. on 15days interval for a total period of 90 days. Prior to start of the experiment, the transported fish were acclimated with the sea environment by rearing them in hapa net for one week. The floating net cages used for experiments were of (Hapas of 1m ×1m×2m sizes, fine-meshed polyethylene (PE) net cages (1.25mm) were fixed in the cages. In the present study, different physico-chemical parameters of water were analysed and all the parameters in the floating net cages were within the suitable and safe range for milkfish culture. This paper gives detailed information on water quality parameters such as water temperature, pH, dissolved oxygen, total alkalinity, nitrite, nitrate, ammonia in brackish water fish culture in floating net cages.