EMBRYOGENESIS ON BREEDING OF WILD CLARIAS GARIEPINUS FROM RIVER BENUE

Abstract

This study technically exposed how embryogenesis on breeding of wild clarias. gariepinus in river Benue   was established for future reference. Male and female broodstock was used in making clearity on the reality of hatching.Injection was administered using ovaprim at 0.5ml/kg of body weight and the male was weight 1.2kg and the female were 700g. Embryo development divided into seven stages of zygote, cleavage, blastula, gastrula, segmentation, pharyngula and hatching period. In the final stage of the embryonic development, the growing embryo occupied the entire previtelline space exhibiting a frequent twitching movement by lashing the tail against the egg capsule. Suddenly after a few seconds the larvae free itself through violent whipping movement of the tail which eventually ruptured the egg capsule. The newly hatched larvae were slender, straight, and transparent. Hatching occurred 20 to 24 hours after spawning. Also the new hatchlings were characterized by the presence of an almost round yolk sac and ranged between 2.5 to 3.1. At this development stage the new hatchlings had no vent or mouth, no swim bladder as the breathe by absorbing oxygen through the fine blood capillaries that surround the yolk sac while still attached to the gut. It was therefore, concluded that two days after hatching the larvae swam freely and by the third day, the larvae had almost completed its morphogenesis by absorbing its yolk sac for further feeding.