EVALUATION OF GROWTH PERFORMANCE OF NILE TILAPIA Oreochromis niloticus, , RED TILAPIA O. niloticus × O. mossambicus, SRIKANDI STRAIN TILAPIA O. niloticus x O. aureus, AND BLUE TILAPIA Oreochromis aureus IN BRACKISHWATER POND  

Tilapia is an euryhaline fish species which can be cultivated in either freshwater or brackishwater pond. Due to the fact that there is a lot of abandon shrimp ponds in Indonesia, increasing national tilapia production require a superior strain of tilapia which is able to grow well in high salinity ponds. This experiment aimed to evaluate the growth performance of three strain of Nile tilapia, i.e. Nirwana strain tilapia O. niloticus, red tilapia O. niloticus and Srikandi strain hybrid tilapia O. niloticus x O. aureus, and blue tilapia O. aureus.

Fish fingerlings were produced by natural spawning of each population in the freshwater earthen pond. The mature broodstock were mated in the spawning ponds at male to female ratio of 10:30. After 14 days of broodstock mating, larvae were harvested and reared in hapa measuring 2x2x1 m with a stocking density of 250 fish/m². The fry were reared for 90 days to reach the fingerling size before they transfered the high salinity ponds for growing-out.

Rearing of fingerling was carried out in the coastal pond sized of  7000 m² in the 3x5 m² net at water salinity of 25-40 g/L  for 120 days. The fingerling were stocked at density of 10 fish/m². Feeding with floating commercial fish feed (30% crude protein) was applied at a rate of 5-10% of biomass twice a day. The observed parameters included of growth rate, survival rate and feed conversion ratio. The results showed that Srikandi strain tilapia revealed the highest growth with final individual weight of 184.83 g, whereas blue tilapia, red tilapia and Nirwana strain tilapia reached the final individual weight of 162.64 g, 146.67 g and 134.34 g, respectively. Survival rate and Feed Convertion Ratio was 76 % and 1.27 (blue tilapia), 81% and 1.29 (red tilapia), 78% and 0.99 (srikandi), 71.5% and 1.44 (Nirwana).  Based on the growth rate, feed conversion ratio, and survival rate, Srikandi strain tilapia had the best performance among others and was recommended as the most suitable candidate for fish culture in the high salinity ponds in Indonesia.