LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF RED TILAPIA AND NILE TILAPIA SPECIES GROWN IN BRACKISH WATER POND

Red tilapia (Oreochromis sp) and nile tilapia (Oreochromis niloticus) has widely distributed  in Indonesia.  Red tilapia and nile tilapia mostly cultured in freshwater ponds. This research was aimed to evaluate lengh-weight relationship and condition factor of red and nile tilapia grown in brackish water pond with salinity ±20 ppt. Research was conducted in Losari, Brebes during June-Oct 2013. Tilapia juvenile with total length  2-3 cm was acclimated in Research Institute for Fish Breeding, Sukamandi.  Juvenile was daily acclimated to 5 ppt/day from 0-20 ppt. Rearing was done in 5x5 m² hapas with mesh size 0.5 cm for five months in brackish water pond. Individual sampling was conducted from 10 % population from 3 hapas, 26 male and 34 female red tilapia and 23 male and 37 female nile tilapia. Result showed that length-weight relationship in male red tilapia is W=0.00933L^3.16  and female is W=0.01096L^2.93. Length-weight relationship in nile tilapia is W=0.01047L^3.08 for male population and W=0.03311L^2.78  for female population. There are strong relationship between total length and weight in red tilapia and nile tilapia (p<0.05). allometric positive was found in male red tilapia and male nile tilapia, and other whise allometric negative was found in female red and nile tilapia. This result indicated that male tilapia growth faster than female in brackhis water pond both in red tilapia and nile tilapia.

Key words : Red tilapia, Nile tilapia, Length-weight relationship, brackish water