Induced breeding of Labeo rohita through single application of ovaprim-C at Faisalabad Hatchery, Pakistan

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, on Labeo 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 number 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.Keywords: Induced spawning, ovaprim-C, fecundity, Labeo rohita.African Journal of Biotechnology Vol. 12(19), pp. 2722-272

Length-weight and length-length relationships of freshwater wild catfish Mystus bleekeri from Nala Daik, Sialkot, Pakistan

Length-weight (LWR) and length-length relationships (LLR) were determined for a freshwater catfish Mystus bleekeri (Day, 1877) collected from Nala Daik, Sialkot, Pakistan. A total of 105 specimens (56 males; 49 females) were collected from February to March, 2010. Each specimen was weighed (g) and measured (cm). The total length of specimens studied ranged from 5.5 to 7.8 cm. Linear regression analysis was used, first to compute the degree of relationship between length and weight and then among total (TL), standard (SL) and fork lengths (FL). LWR exhibited a highly significant correlation (P < 0.001). The overall value of the exponent of LWR (b = 2.62) suggested negative allometric growth. Results for LLRs indicated that these are highly correlated (P < 0.001). Furthermore, the first reference for separate male, female and combined sex of length-weight and length-length relationships for Mystus bleekeri was provided.Key words: Mystus bleekeri, length-weight relationship, length-length relationship, predictive equations