Effect of different salinity level on spawning, fertilization, hatching and survival of common carp, Cyprinus carpio (Linnaeus, 1758) in semi-artificial environment

The effects of various salinity levels among (0‰, 5‰, 10‰, 15‰, and 20‰) for successful breeding of Common carp, Cyprinus carpio were investigated. The duration of study was 75 days. Ripe broodstock (30) having a mean weight (male 1027±2.4g and female 1084.8±23g) were selected and stocked into spawning tanks (2000-liter). The Ratio among male and female was 2:1. They were fed with commercial floating pelleted feed having 35% crude protein with 2% body weight twice a day. Broodstock were injected with Ovaprim hormone 0.5 mg/kg female and male 0.2 mg/kg, respectively, after successful spawning broodstock were removed from spawning tanks. Results showed that the highest fecundity, fertility, hatchability and survival of fry were obtained on salinity of 0‰ to10‰ and significantly decreased on 15‰ and 20‰. The eggs per gram body weight were also recorded in all treatments and highest eggs were obtained, i.e. 45-60 per female on salinity of 0‰-10‰.  Water temperature (22.4±0.2°C), dissolved oxygen (6.5±0.2 mg/L), pH (7.2±0.2) and ammonia (less than 0.03±0.06 mg/L) were monitored throughout the study period. Water quality parameters remained within the recommended range. Our results suggest that common carp, Cyprinus carpio may give maximum eggs up to 10‰ salinity with 81% survival of the fry.