Use of Hormones in Induced Spawning of Carps

The role of hormones in regulating the ovulation and spawning in fishes is still controversial and inconclusive. Although remarkable progress has been made during the last decade in studying the effect of various hormones on the reproductive physiology of a number of fishes, little information is available on the regulation of hormones in the spawning of the difficult-to-spawn carps, namely the major Indian and Chinese carps. These important cultivated species, although they attain maturity in ponds, fail to reproduce in that environment in the absence of external stimuli which are essential for the release of gonadotropins resulting in ovulation and spawning.Attempts made to breed these carps by injections of mammalian hormone preparations did not meet with much success. Administration of fish pituitary hormones, on the other hand, induced ovulation and successful spawning in these fishes. While extensive use of crude pituitary treatment for production of carp seed is in vogue in pisciculture all over th...