VPP 322: Aquatic Animal Diseases, Health Care and Management (1+1)

SELECTION OF BREEDERS

• The selection of healthy breeders is a pre-requisite for successful breeding. The male and female breeders are first identified based on the distinguishing features (Table.1).
•  They are stocked separately in a fertilized pond at the rate of 1000 - 2000 kg/ha, a few months prior to the commencement of actual breeding.
• They are well fed on ground oilcake and rice-bran in the ratio of 1:1 at the rate of 1-2%  of the total body weight.
• The effectiveness of pituitary injection depends mainly on the coincidence of the time of treatment with the suitable period of the sexual cycle of fish.
• Mature and ripe males and females have to be selected to get best results. The maturity stages of the male and female fishes are given in Table-2

Female carp	Bulged belly of the female carp

Table 1. External distinguishing features of sexes in carps

Female	Male
Pectoral fin relatively small and weak with the outermost ray not very thick	Pectoral fin relatively long and prominent with well-developed thick outermost ray.
Inner surface of the pectoral fins, facing the body, is smooth to feel by touch	Inner surface of the pectoral facing the body, is rough
Abdomen shows a conspicuous bulge which extends past the pelvis up to genital aperture. Abdomen soft to touch. Bulge in the abdomen may also be due to fat deposition around the gut and is not a foolproof indication of maturation of gonads.	Abdomen does not show a conspicuous bulge and not very soft to touch. Abdomen shows median ridge in front of vent.
Genital aperture is protruding and swollen, turgid, shows pinkish margins. A pinkish genital pore may also be found among fish which may begun to regress	Vent not protruding; pit-like appearance
Ova visible inside genital aperture	Milky white milt exudes through
Body stout in appearance relative to male of same age adult	Body thinner and linear relative to adult females of same age

Genital organ of matured female carp	Genital organ of matured male carp

Table 2. Seven stages of gonadal maturation of carps

Stage of maturation	Condition of gonad
	Female	Male
Immature	Transparent, long, narrow strip-like ovary	Transparent, thread-like testis
Immature	Thickened strip, Translucent ovary	Translucent, thread-like testis
Early maturing	Ovary is opaque, granular somewhat grayish, occupying about 1/3 of body cavity	Ovary is opaque, pinkish white, thin and strip-like
Late maturing	Dull grayish colour; ova discernible like granules, occupying about ½ of the body cavity	Thick strip, milky, oozing whitish fluid on applying pressure on belly
Mature	Dull grey to greenish occupying almost the entire body cavity, ova distinctly round in shape	Thickened band like, oozing whitish fluid on applying pressure on belly
Spawning	Having loose eggs in ovarian wall, eggs oozing through genital aperture on applying pressure on belly	Milt oozes freely on applying pressure on belly
Spent	Ovary blood-shot, pinkish brown mass but greatly shrunk	Traces of milt can be seen, shrunken and blood-shot testis

View video- Stripping a male carp for breeding ....