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3.6. Induced breeding of Indian major carps
Unit 3 - Breeding of major carps
3.6. Induced breeding of Indian major carps
- Breeding of fish with pituitary gland (hypophysis) extract is termed as Hypophysation
- The credit for developing the technique of hypophysation in the world goes to the Brazilians, while the pioneers of hypophysation of Indian major carps are H.L.Chaudhary and K.H.Alikunhi.
- Induced breeding refers to inducing fish to release gametes through the application of pituitary extract or hormones or chemicals.
Identification of sex of brooders
- Identification of sex is a prerequisite to induced spawning of the fish.
- Fish is sexually dimorphic and sexual dimorphism is exhibited primarily by gonads and their ducts and this involves killing of fish.
- Alternatively, the sex is identified based on certain morphological/external characteristics which include size, length, weight, colouration, fin characteristics, modification in the head in the form of nuptial dress, genital opening, width of mouth, etc.
- Carps are sexually dimorphic i.e. mature male and female are morphologically different.
- Some of the external morphological characters which are developed during breeding season could be used to identify sex in major carps which mature during their 2nd or 3rd year.
Characteristics | Male | Female |
1. Scale, Operculum and pectoral fins | Rough to touch, particularly the dorsal surface of pectoral | Pectoral smooth to slippery |
2. Abdomen | Round and firm | Swollen and soft |
3. Genital opening swollen | Elongated slit, white in colour, not swollen | Round and pink |
4. When pressure applied on abdomen opening | milky white fluid oozes through genital opening | a few ova may ooze through genital |
5. Shape of body and size | Body linear, swollen |
stouter, slightly larger |
Male (top) and female (bottom) catla brooders
Last modified: Thursday, 9 June 2011, 10:47 AM