Abstract

A study was conducted to observe the effect of intramuscular injection of Ovaprim–C on the number of eggs/kg, fertilization rate and hatching percentage at a private fish hatchery and research center at Faisalabad, Pakistan, during May to June 2008, onLabeo rohita (Rohu). Studied fish specimens were spawned successfully following a single dose of injection of Ovaprim-C (LH-RH analogue) with 0.4 ml kg^-1 for female and 0.05 ml kg^-1 for male brooders. Ova and milt were stripped simultaneously and mixture was stirred for 15 to 30 s during which fertilization occurred. Hatching occurred within 18 to 30 h after fertilization. The experiment was conducted in circular spawning tank with 2 m diameter. If it is impossible to determine the absolute and relative fecundity, then these parameters can be determined from the body weight. Average no. of eggs/kg, fertilized eggs/kg and hatchlings/kg was 63574, 49067 and 39952 respectively. Overall fertilization and hatchling %age was 77.50% and 81.39% respectively. Wet body weight was observed to have a positive influence on absolute (r=0.983) and relative fecundity (r = 0.910) in log-log scale.

Key words: Induced spawning, Ovaprim-C, fecundity, Labeo rohita.