STUDIES ON THE REPRODUCTIVE BIOLOGY AND INDUCED SPAWNING OF MURREL, Channa marulius

Abstract

The present project was planned to study the reproductive biology and induced spawning of Channa marulius in captivity. Planned study completed in three trials. In the 1st trial fingerlings were kept in (90’x70’x4’) replicate ponds. There were two treatments and a control pond. Treatment 1 had 40% protein and Treatment 2 had 50% protein while control had the lowest level of 30% protein. The results showed that the maximum dietary protein levels in the feed and occasional sorting of Channa marulius fry had a positive impact on growth, survival with reduction in cannibalism in the earthen ponds. The maturation cycle and reproductive biology studied by sacrificing replicate sample of fishes in each month. Like earlier trial feeds with different protein levels were offered to fish. Diet with the highest protein again showed superiority in growth and development of gonads in both male and female Channa marulius. Adult Channa marulius average size (948.02±4.74g) collected from brood stock earthen ponds. The fish fed regularly 40% protein diet at 5% of their body weight for the period of 365 days. Close to the breeding season males attained 1100-1340 g weight while females attained 1150 to 1350g. Mature males and females identified based on their external morphology. In the breeding of Channa marulius, different doses of Ovaprim (Syndel International Inc., Canada) hormones i.e. 0.2, 0.4, 0.6 and 0.4 ml/kg body weight injected to Channa marulius, and in the second dose 0.2 and 0.7 ml/kg were inject to male and female respectively. Channa marulius failed to spawn with the sole injection of Ovaprim. However, when ovaprim combined with fresh pituitary gland and /or other hormone analogues, fish spawned successfully. In another experiment, the effect of different dietary protein levels on the spawning success of Channa marulius evaluated. Broodstok fish fed on diet containing 40%CP, 35%CP and 30%CP levels collected from respective earthen pond, acclintized in hatchery tanks and injected with ovaprim. This breeding experiment revealed that 40% protein containing diet not only improved brood stock health, enhanced growth, advanced maturation (gonad development) but also increased fish fecundity. Different synthetic hormones administered with different combination and doses. Broodstock fish selected for induced spawning from 40%CP containing feed treatment. HCG, HMG and Ovaprim were injected in the following combinations; HCG+Ovaprim (0.3+0.5ml/kg body weight), HCG+HMG (0.3+0.5ml/kg body weight), and Ovaprim +HMG (0.3+0.5ml/kg body weight). The findings of this experiment this experiment depicted that a combination of human chorionic gonadotropin + human menopausal gonadotropin (HMG) and Ovaprim+ HCG are effective and reliable synthetic hormones for the induction of ovulation in Channa marulius and can be helpful in spawning and stock replenishment programs.