Finfish Breeding and Hatchery Management

Breeding technique
● Induced breeding of carps starts with the onset of south-west monsoon, i.e. June.
● Collect the ripe male and female brooders from the brood-stock pond with a drag net having a mesh size of 12 mm
● Condition  them in hapa with running water for a few hours prior to injection.
● Make sets of  brooders, each set consisting of  one female and two males
● Take weight of each brooder with a hand net stitched in the shape of a bag
● Inject female brooder with a higher dose (0.3-0.5 ml/kg body weight) spawning agent such as ovatide or ovaprim or pituitary extract and male brooder with a lower dose (0.1- 0.2 ml/kg body weight)
● The active ingredients in ovatide are mLHRH-a and domperidone, while in ovaprim the active ingredients are sGnRH-a and domperidone
● Give injection in the tail region, behind the dorsal fin and above the lateral line, for best results
● Use a glass or disposable syringe of 2.0 ml capacity, having 0.1 ml graduation to administer spawning agent.
● Use needle number 22 for fish weighing 1-3 kg, No. 19 for larger fish (>3 kg) and No. 24 for smaller fish (<1 kg).
● Release the injected brooders in breeding hapa or breeding cage or circular breeding tank
● A breeding hapa is a box-shaped cloth enclosure made of long cloth, generally of  size  2 x 1 x 1 m with provision to close its top after releasing brooders.
● Fix the hapa in a tank or pond with flowing water.
● Do not disturb the brooders while they are involved in courtship.
● Spawning takes place during night
● The following morning, remove the spent  brooders, disinfect with a solution of  KMnO₄ and transfer them to a prepared pond.
● Collect the developing eggs from the breeding tank, note down their quantity and transfer to a suitable hatching device for hatching.