The Difference Between Recirculation Tank System and Water Flow System For Breeding Parent Stock Seabass (Lates calcalifer Bloch)
The development of seabass cultivation , has great opportunities because it is supported by the competitive advantage of our territorial water that is vary large includes sea water,salty water and fresh water. The biological characteristic of seabass is very advantageous to be cultivated because they are able to adapt to salinitas changes ( euryhaline ). seabass is one of the top of sea fishery that has high economic value. In addition it has very big market both local and international.
The management of parent stock is one of the first step to get good quality of eggs to be used for maintaining sustainability of seabass seeds. The parent stock of seabass at BPBL Batam are cultivated by using 2 methods.
1. Recirculation method
2. Water flow method
The differences of the both methods are:
In Recirculation method, the parent stock are cultivated in water tank with capacity 15M3 . Recirculation system of water is implemented where the outgoing water from the tank isn't directly flushed out through outlet pipe, but the outgoing water is recirculated to the cultivation tank .The water is recirculated to the cultivation tank through a series of filtering process among others are,sand filter, bio filter and UV filter.
At the other hand in Water flow method , parent stock of seabass is cultivated in tank with capacity 15 M3, but the incoming water will directly come out through outlet pipe without being recirculated into the cultivation tank.
Based on the observation it is found out that ,in recirculation system parent stock seabass can breed naturally without having environment manipulation, They can breed for 7-8 days in a raw and the amount of eggs is bigger than the water flow system. At the other hand , the water flow systemparent stock seabass can breed naturally but they must be given stimuli such as environment manipulation .They can breed 5-6 times , but the breeding isn't in a raw. In addition the amount of eggs is also less than recirculation system. Based on the water inspection, it is found out that DO in recirculation system is 6,3 -6.9 mg/l. There is no amoniak in cultivation tank, Ph is around 7.5-7.7., water temperature is 29-29,5 degree Celsius, salinity 33 ppt, total common bacteria is 5.9 x10₂ -9,3 x 10₂ different from controlled tank that has DO around 4-4.7 mg/l ,NH3 arround 0.3 -0.9 mg/l ,Ph is around 6.6 -7.0 ,salinity is 33 ppt and water temperature is 28-29 degree celcius , total common bactery is 1.19 x10 ᵌ - 10.2 x10.ᵌ