COMPARATIVE EVALUATION OF GROWTH AND PROFIT OF SEA BASS Lates calcarifer (BLOCH) CULTURE IN COASTAL CAGE FARMING BASED ON HARVEST DURATION

: Cage aquaculture is the technology of the millennium aiming increased production of commercially important quality fishes in for domestic and export markets, in healthy natural water resources while being enclosed in net cages which allow free flow of water. The new cage design and efforts of CMFRI during the last decade has considerably boomed cage fish farming in the open waters of Kerala especially in Ernakulum, Thrissur and Alleppey districts.  A comparative study was conducted in two coastal cage farms one in Moothakunnam (T1) and another in Kottappuram (T2).  Studies were conducted in both sets of cages for duration of one farming i.e. around one year and evaluated the growth of sea bass in two different locations and its economics till the harvest.

Juvenile Asian Seabass with an average weight of 8 gm and length 6.5 cm were randomly stocked in GI cages (4 × 4 m) in triplicates in both the places. The fishes were fed with low value fishes at 6-8 % of body weight twice daily. The water quality parameters monitored were observed within suitable ranges. First sets of fishes harvested after 9 to 10 months of stoking whereas the second sets of fishes harvested only after one year of culture.  Results of Growth, Survival, and Production along with Water quality parameters monitored and recorded for further analysis. The growth parameters in terms of body weight, length, weight gain, survival rate etc. were measured and presented.   The results were analyzed and found significant difference in growth.   The net profit value was found higher in T1 than T2.  Significant differences were also observed in the profit percentage as well as in the MSY.  FCR value is comparatively low in T2.  The water quality parameters studied are nitrate (0.631+1.57), nitrite (0.0951+0.0765), ammonia (0.0174+0.0618) and orthophosphate (0.067+0.06342).

Therefore it can be concluded that the growth performances of Sea bass is directly proportional to feeding and time however, the net profit is found decreasing as the culture duration exceeds a period.