INTEGRATED MARICULTURE IN TOMINI BAY, GORONTALO PROVINCE
Integrated marinculture among culturing grouper fish, shells and seaweed. This research aimed to adopt and simulate the development of multi marine culture efficiently for water health environment. Our location was at Tabulo South Village, District Mananggu Bualeno, Gorontalo Province. The development of marine culture area is about 4 ha used 5 oval cages with d = 10 meter and 6 cage sized 5 x 15 meter. The other components integrated to the cages as the low trophic level commodities were used 6 units of long line culturing shells and 14 units for seaweed.
The main commodity was hybrid grouper averagely weight 100-150 g farmed into 5 x 15 x 5 meter cage net and the oval cage net with d = 10 meters and 5 meter depth then they proposed to restrain density about 1000 fishes/cage. The grouper fish was feeding by sardine 4-8 % from its weight per day. The long farming of this culture was six months.
The lower trophic level was selected shell and seaweed. The both cultured into long line system. The shell and seaweed was set into long line in drowned 4 meter from surface. Long line systems were placed in west and east from cage net accordingly with water current flow. Culturing seaweed in this research was E. edule and K. alvarezii for each one also expanded onto nylon rope as long as 35 x 15 m. The seeds were gathered from local seaweed farmer and cut to be 50 g then tied onto nylon rope interval 15 cm/seaweed.
The hybrid grouper cultured by square and oval cage. During 5 months was increasing the biomass weight respectively in square cage 514 to 1521 kg and oval cage 517 to 1568 kg. Feed convention ratio (FCR) for square cage and oval cage were about 3.8 and 4.3. Therefore the density increased 74% (square cage net) and 76% (oval cage net), productivity of grouper was estimated 4 kg/m3. For shell culturing in 5 months decreased the biomass weight from 500 kg to 150 kg with rate growth 0.02% and density about 24%. Otherwise seaweed culture showed the positive result that E. edule and K. alvarezii increased respectively 370 and 424 % of the biomass comparing with the control result. Total adsorption of nitrogen in E. edule achieved 82 kg/N/ ha lower than K. Alvarezii 67 kg N/ ha/year. Meanwhile total phosphorous adsorption was about 25 kg P/ha/year for E. edule lower than Alvarezii 14 kg/ha/year.
Total nutrient loading in this research was respectively about 653 kg N and 169 Kg P including residual feed and excretion would be adsorb by seaweed effectively 451 kg N and 136 Kg P. Integrated mariculture gave benefit including productivity of fish product and water health environment.