physical, chemical and biological factors of water. Breeding, hatching, nursing, rearing and stocking fishes in ponds has to be managed properly. Keeping in view the various stages of fishes, the following different types of ponds have been recommended to manage them. Breeding pond The first step in fish culture is the breeding of fishes, therefore, for proper breeding special types of ponds are prepared called breeding ponds.
These ponds are prepared near the rivers or other natural water resources. Types of breeding Depending on the mode of breeding, they are divided into . Natural breeding (Bundh breeding) These are special types of ponds where natural riverine conditions or any natural water resources are managed for breeding of culturable fishes. There bundhs are constructed in large low-lying areas that can accommodate large quantity of rain water.
The shallow area of such bundhs is used as spawning ground. . Induced breeding The fish seed is commonly collected from breeding grounds but does not guarantee that all fish seeds belong to the same species. Hence advanced techniques have been developed to improve the quality of fish seed by artificial method of fertilization and induced breeding.
Artificial fertilization involves removal of ova and sperm from female and male by artificial mechanical process and the eggs are fertilized. For artificial fertilization the belly of mature female fish is held upward. Stripping is done with the thumb of the right hand from the anterior to posterior direction for the ejection of eggs due to force. In this way eggs are collected separately.
Further, the male fish is caught with its belly downwards. The milt of fish is striped and collected separately, and then the eggs are fertilized. Induced breeding is also done by hypophysation (removal of pituitary gland). The gonadotropin hormone (FSH and LH) secreted by the pituitary gland influences the maturation of gonads and spawning in fishes.
Pituitary gland is removed from a healthy mature fish. Pituitary extract is prepared by homogenising in . % saline or glycerine and centrifuged for minutes at 8000rpm. The supernatant is injected intramuscularly at the base of the caudal