Question

32. What is the use of induced breeding? Ou Answer A. To fulfill the requirement of fish seed for fish culture B. Breeding of Indian Major Carp D. All of the above C. To increase the production fish culture​

Answer 1

Explanation:

Availability of required quantity of fish seed of desired species is one of the most important pre-requisite for successful fish farming. The widely cultured Indian major carps in inland waters like catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigala) and calbasu (Labeo calbasu) and Chinese carps, silver carp (Hypophthalmichthys molitrix), big head (Aristichthys nobilis), grass carp (Ctenopharyngodon idella), black carp (Mylopharyngodon piceus) and mud carp (Cirrhina molitirella), normally do not breed in confined waters. They do mature there, but only breed in the flooded shallow areas along the course of the rivers during monsoon months which are their natural habitat. The Indian major carps do spawn in the specialised environments of bundhs, both wet and dry where lot of rain water is accumulated during monsoon period. Under such circumstances the fish culturists had to depend for the fish seed on collection from river systems and the collected fish seed consisted of not only of desired species, but also of uneconomic species including predators. The inability of Asiatic carps to breed in confined stagnant waters is owing to the lack of needed ecological stimuli to effect secretion of required quantity of gonadotrophic hormones and so extraneous hormones such as pituitary extract or synthetic hormones are injected to brood fish to induce them to breed. The first success in inducing the Indian major carps was achieved in 1957 (Chaudhuri and Alikunhi, 1957) and in silver carp and grass carp introduced in India in 1959, in the year 1962 (Alikunhi et al., 1963).

1.1 Pituitary Gland Collection and Preservation

In India, generally, pituitary glands are used as an inducing agent to breed Indian major carps and Chinese carps. The glands are collected from fresh gravid fishes as well as fishes well preserved for a period of a week or so. Using a sharp butcher's knife the scalp is removed exposing the brain. The entire brain is lifted carefully, disconnecting the olfactory and optic nerves.

On removal of the brain, the pituitary gland can be seen covered with a membrane, thin or thick

Answer 2

Answer:

Induced breeding refers to inducing fish to release gametes through the application of pituitary extract or hormones or chemicals.