COMPARATIVE STUDY ON THE INDUCED BREEDING PERFORMANCE OF ROHU (Labeo rohita) OBTAINED FROM HATCHERY AND NATURAL SOURCES

In order to observe the breeding performance of Labeo rohita with PG (Pituitary gland), the study was conducted during the breeding season from April to July 2012 with the Rohu brooders obtained from Sonali, Rupali, Mafatema fish hatchery and natural source (Boluhor baor) at Jessore. Male fish was given only one injection with PG at the rate of 2 mg/kg body weight. The female was injected with 2 mg/kg for the priming dose and 6 mg/kg for the resolving dose after 6 h of the priming dose. The male and female fishes were stripped simultaneously and the ova and milt were mixed by stirring for 15 to 30 second for fertilization. Hatching occurred within 20 to 22 h after fertilization. The highest fertilization rate (80.76 %) and hatching rate (70.98 %) were found in Rupali fish hatchery. Regression analysis was applied to assess the relationship among body weight, gonad weight, length and fecundity. Linear and positive regression line was obtained between total length-fecundity, gonad weight- fecundity and body weight- fecundity. It was observed that body weight, gonad weight and length have positive relation on fecundity. Highest gonadosomatic index of Rohu was found also in Rupali fish hatchery (20.32 %). Hatchery brood stock showed better breeding performances than natural brood stock.