Explain the term hypophysation.

Hint:-Pisciculture or fish farming deals with the commercial rearing and breeding of fish in artificial and induced conditions. In induced breeding, the necessary hormone is introduced into the animal to stimulate the desirable and timely release of gametes.

Complete Answer:-Reasons involving environmental parameters like rain, photoperiod, temperature, and rate of water currents have forced breeders to compulsorily choose induced breeding techniques over captivation techniques if they desire good quality, regularly breeding, and pure spawns. The ease and relatively low cost of these techniques have made it easier for breeders all over the globe to adapt them.
Induced breeding is also called hypophysation because it basically requires injecting certain endocrine agents (pituitary gland is also referred to as hypophysis) into both the male and female fishes. These agents may be natural such as pituitary extracts or they may be synthetic agents like steroids, drugs, and mammalian gonadotropin.
 The steps in hypophysation are:
· The pituitary glands are obtained from ripe fishes by carefully carving out the skull (sphenoid bone)
· Then, they are stored in moisture-free areas for the glands to be soluble in water. The storage techniques include alcohol or acetone preservation and quick freezing.
· Lastly, preparation of extract and injection of optimum dosage into the selected fish’s anterior caudal region.

Note:- Pisciculture deals with the culture and maintenance of fish only while aquaculture refers to breeding and rearing of all aquatic organisms like fishes, prawns, seaweeds, oysters, and aquatic plants. Thus, Pisciculture is a subcategory of aquaculture.