CHINESE CIRCULAR HATCHERY Prepared By:- Juned Pathan

Introduction It is also known as eco-hatchery or circular hatchery. Circular breeding & hatching tank in which water flows in a Circular or centrifugal motion originated in china. Such type of hatcheries are used for hatching carp eggs and popularly known as the Chinese type of carp hatcheries.

Conti… Within a small space, this system stimulates some aspects of riverine environment and has proved itself to be a very successful method for breeding carps for commercial production of carp seed. In modern times, more and more hatcheries are incorporating circular breeding tanks with continues water flow.

SITE SELECTION The location of site and general arrangements will have controlling impact on the economics of operation. For successful fish production business, suitable site is most important.

CHINESE HATCHERY’S COMPONENT The hatchery complex consists of : Over head tank . Spawning tank. Incubation tank. Spawn receiving tank.

Over head tank The water requirement for hatchery operation is regulated through an overhead tank. The size of overhead tank is depending upon the dimension of circular tank. The floor of tank is to be 2.6 mt. above the ground level. Capacity : 30000 liters.

SPAWNING TANK The circular spawning tank of about 8 mt diameter. It is made up of brick masonry, R-C-C. It is at higher elevation than incubation tank, so that by gravity water can be transferred from spawning tank to incubation tank. The inner depth of the tank at the periphery is 1.20 mt. Sloping bottom towards center.

Conti… The height from central at 1.5 mt . Outlet pipe of 10 cm. dia. is provided at the center. Central outlet for transfer of fertilized eggs to incubation tank for hatching. The outlet is connected to 2-3 incubation tanks through “T” connectivity, provided with individual control valve.

Conti… The wall of the tank is provided inverted “L” shape nozzle with 14-16 inlet pipes at 45’ angle in order to create a circular movement. The top of the tank certain pipes are provided with shower to create condition just like rainy season. The periphery outlet is provided at 60,70 & 80 cm level.

SPAWNING POOL SPAWNING TANK

INCUBATION TANK After spawning fertilized eggs are transferred to the incubation tank. The incubation circular tank can be 2 or 3 internal diameter of 3.6 mt. Each incubation tank has two chambers. Outer chamber is made up of masonry / concrete wall.

Conti… The inner chamber is provided with fixed mesh screen. Screen or iron rods which has 0.74mt. Distance from the outer wall. The inner chamber is provided with 10 cm. dia. Vertical outlets with couplings of 4 inch height to regulate the water level in the incubation tank.

Conti… The over all dimension of the outer chamber is 4 mt having a outer masonry / concrete wall. The partition is done with rough mesh net & on the bottom of the outer chamber 8 duck beak inlets are provided. The rate of water flow is 0.2-0.3 m/sec. after 3 days the hatchlings are transferred to spawn receiving tank.

INCUBATION TANK

SPAWN RECEIVING TANK The spawn receiving tank in which hapa is fixed in order to facilitate easy collection & distribution of spawn. It is a rectangular masonry / concrete tank. The inside dia. Is 4*2.5*1.2 mt. Located at the lower elevation then the incubation tank.

Spawn receiving tank

Mode of Operation The injected spawners are released into the spawning tank in the female – male ratio of 1:1.5. The capacity of 8 m dia spawning tank can be used for accommodating 60 kg females and 90 kg males to produce about one crore eggs in single operation. The water level in the tank is maintained at 60-70 cm during spawning.

Cont… The rate of water circulation to be maintained initially at 2-4 RPM whereas at the spawning time the rate is reduce to 1-2 RPM so as to enable better chance of fertilization in mild flow. The center outlet is close & excess water is drained out through peripheral outlet. After the spawning the spent breeders are dragged out and central outlet is opened to transfer the fertilized eggs into incubation tank.

Cont… In incubation tank rate of water flow- 1RPM but at the time of hatchling. The rate is increased to 2-3 rpm for supporting better hatching process. The hatching period in normal temp is 14-16 hours.

ADVANTAGES: Handling is minimum. Continues process. spawning & hatching efficiency is higher. survival of spawn is more. Free from environmental hazards. Recurring cost is not required Mass scale breeding is possible. Easy to breed Chinese carp .

DISADVANTAGES Initial investment is higher. Not suitable for small scale operation.

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