STUDY THE OPTIMUM CRUDE PROTEIN FOR GREY MULLET Mugil cephalus SEED IN FLOATING NET CAGES

Cage aquaculture is an important technology to increase fish production. A widespread and profitable culture of fish and prawns in cages has already been developed successfully in Asia, Europe and America. In cage aquaculture technical simplicity with which farms can be established or expanded, lower capital cost, feeding, growth and health of stocked fishes can be monitored on a daily basis without much disturbance, cultured species are well and harvesting of cultured species would be easier and cost effective. As caged fish are generally fed with high protein diets  The present study were conducted at the closed bay near Suryalanka, Bapatla, Guntur district Andhra Pradesh.

The Experiment  was  conducted  to study the optimum crude protein for grey mullet, Mugil cephalus seed in floating net cages. Mullet fry were obtained through natural seed collection. Rectangular floating net cages made of bamboo poles were provided inside with 1×1×2m hapas. Predatory net and bird net were provided. PVC drums filled with air were fixed to the net cage for floating. Mullets with mean body weight of 0.95 g were stocked at the rate of 40 fish/m³ in each hapa in the rectangular cages. Triplicates were maintained for each treatment. Fish fry were fed with 5 artificial dry diets containing 12.5% (Control - C (T1)), 15% (T2), 25% (T3), 35% (T4) and 45% (T5) crude protein. The diets were fed at the rate of 10% of the biomass for a period of 63 days (9 weeks). Water quality parameters like D.O, pH, salinity, NH₃, NO^-2, NO^-3 and temperature were estimated at weekly intervals and were within the optimum range for culture of mullet. At the end of 63 days growth experiment, fishes fed on 25% (T3) crude protein feed exhibited highest growth and survival performance at 1% and 5% level of significance. The present study showed that Mullets seed reared in floating net cages in the closed bay performed best at 25% crude protein.