Finfish Breeding and Hatchery Management (2+1)

Selection of  broodfish  and breeding technique
● Identify and select mature broodfish based on their morphological characters.
● Male has round abdomen and whitish genital opening; oozes milt when slight pressure is applied on abdomen.
● Female is stouter, has soft and swollen abdomen; a few ova may ooze out when pressure is applied on abdomen.
● Release mature male and female in a cement tank (25 m³) with running water at a ratio of  2 : 1.
● Release aquatic plants like Hydrilla or Vallisnaria or Eichhornia  as a substratum in the breeding tank for the attachment of eggs; synthetic fibres can also be used in place of plants  
● Disinfect the plants with a solution of KMnO₄ and introduce 2 kg plants for every one kg female
● Take the weight of female brooder  before and after spawning in order to estimate the quantity of eggs released, allowing 5-10% towards  loss of   weight due to excreta.
● If required, inject the brooders (at 0.2 ml/kg b.w.) with synthetic spawning agents to ensure better results
● Provide water showers in the tank to facilitate better spawning
● The total quantity of eggs released can be calculated using the formula:
Total quantity of eggs released = Loss in weight (g) x 700        
Where, 700 is the number of eggs per g ovary weight.
● After spawning, remove the brooders from the tank, disinfect and transfer to a freshly prepared pond.