Peningkatan produktivitas air tawar melalui budidaya ikan sistim akuaponik

Decreasing water productivity, -as it is reflected by a declining value of water use- is a current phenemenon of water resource crisis. On top of the issue, water shortage in term of quantity and quality is a main cause of the crisis. This crisis can be solved by application of so called aquaponic based fish culture . The aquaponic system is principly a culture technique combining an aquaculture and hydroponic in which fish and plant(s) are reared together in a one system in order to increase the productivity of water and pond. This system enables optimzing utilisation of disposed nutrients from fish farming to to produce crop (vegetable). It is deemed to be environment friendly because of it’s Capacity to reduce the waste of farming into minimum level. In this research, the aquaponic system is made up of nine (9) units of fiber tanks in size of 500 liters water volume each. In each tank, 50 Nile tilapias (Oreochromis niloticus) were stocked with an initial weight ranging from 13,36 to 14,86 grams . The fishes were fed with dry pellet in dosis of 3% to the total biomass, which is given three times in a day. In this research the experiment unit was arranged as a recirculated system to enable water flows continously through coral stones as a filter. Ipomea aquatica, a vegetable with local name Kangkung, was used as experiment species. .The experiment applied a complete randomized design with 3 different treatments based on filter spaces : A (experiment with (25% of filter space), B( 50% filter space) and C (experiment with no filter). Each treatment was replicated 3 times. Fish growth observations on two parameters, weight and length of fish have been done every 14 days upon a 10 % sample of fish population in each unit. Fish survival rate was recorded at the end of the experiment. Data on total production of Kangkung was made by wrapping up all harvest records. Seven parameters of water quality were observed and monitored. These are temperature, pH, dissolved oxygen, ammonia, nitrite, nitrate and total alkalinity. Results of the experiments showed that after 3 months the average of individual weight of nile tilapia was 50g; There was no significant difference in fish growth and survival rates among three treatments (P>0,05) . The best vegetable harvest record was performed by treatment B(50 % space filter). It is also shown that water quality parameters supported sufficiently for fish to grow. The experiment has confirmed the proposition that the application of aquaponic system improves water productivity on fish farming and is environment friendly.