2. • The silver carp and grass carp are native to China and hence are known as exotic
carps
• First introduced into India in the year 1959
• Both were successfully induced bred in 1963, through hypophysation
• The method of hypophysation of these species is similar to that of IMC
• However, there are a few minor differences – the dosage of pituitary is double
compared to IMC and, unlike IMC, they do not spawn naturally after injection, in
captivity.
Figure: Silver carp Figure: Grass carp
3. • The sex of brooder is identified based on the morphological characteristics such as
fins, abdomen, genital opening, etc.
• The same critera that are used for IMC can also be used for silver carp and grass
carp
• Although they can spawn naturally when fed on artificial diet, instead of aquatic
plants, realization of spawn will be lower
• To facilitate better fertilization, the eggs need to be stripped by applying pressure
on the abdomen and eggs fertilized by mixing with similarly stripped milt
• Of the two methods of fertilization, the wet method is more successful
Figure: Male (top) and female (bottom) grass carp brooders
4. Fertilization of eggs :
• After hormone injection, the male and female brooders are released separately in
breeding hapas
• The female brooder is checked for ovulation at 3-4 hours interval
• After ovulation, the female is stripped and the eggs are collected on to a clean
basin/tray, avoiding any contamination with faeces, mucus, blood, etc.
• Eggs are then mixed with milt stripped from more than one male (preferably 2-3
males) to ensure better fertilization as these fishes produce comparatively less milt
• The water-hardened developing eggs are transferred to incubators for hatching
• The method of hatching of eggs and hatching period are same as that of IMC
