SPAWNING RESPONSE OF SAHAR Tor putitora IN TERAI REGION OF NEPAL  

Sahar (Tor putitora) is a high value indigenous riverine species of Nepal which is declining in its natural habitat and has been declared an endangered species. Limited seed production of this species in the temperate region has restricted for expansion in culture as well as rehabilitation in natural waters. An experiment was conducted at the Department of Aquaculture and Fisheries, Agriculture and Forestry University, Rampur, Chitwan during August 2014 to April 2015 to explore and assess the breeding performance of sahar in the Terai region of Nepal, which has a subtropical climate. Twenty eight male (0.5-1.5 kg) and 35 female (0.8-2.5 kg) brood fish were reared in ponds at 1000 kg/ha and provided 35%  protein feed at 3% body weight per day. Maturity was observed by sampling fish and applying pressure to the abdomen to express gonads biweekly during off-season; this frequency was increased to every third day as breeding season approached. One female sahar of 3-5 years old was ready for breeding in March when the water temperature was 23.3-25.2 °C. In the same month, another female responded to injection of inducing hormone (ovaprim) at the rate of 0.5 ml/kg when the temperature was 25.3-28.7 °C. Males about 1-2 years old were expressed milt in almost all months during experiment. Ova from mature females were obtained by simple hand stripping method and fertilized with milt collected from males manually. The fertilized eggs were incubated in Atkin hatching trays. Survival and growth of the fry were high (Table 1) and maturation details were similar to fish spawned under temperate conditions. This study demonstrated that natural and induced breeding and fry rearing is possible in the Terai region of Nepal. However, further studies on synchronization of breeding time and mass seed production are recommended.