Degree-Hours to Spawning Response, Fertilization Rate and Hatching of Hypophthalmichthys nobilis and Cyprinus carpio through Induced Breeding by using Ovaprim under a Captivity

A breeding experiment was conducted on Hypophthalmichthys nobilis and Cyprinus carpio April to August 2022 at Tawakkal Fish Hatchery at Muzaffargarh, Punjab, Pakistan. A single dose of intramuscular injection of Ovaprim with 0.7 ml/kg for female and 0.2 ml/kg for male brooders of both species were administrated. After hormonal adminteration brooders were kept in the circular tank for spawning. The 100% ovulation rate was observed in both species. Spawning response was observed after the latency period of (8.80±0.1-10.84±0.02 hours) and (8.1±0.26-9.8±0.01 hours) in Hypophthalmichthys nobilis and Cyprinus carpio respectively at water temperature range from 22-28 °C. Fertilization rate (61-73%) was observed in Hypophthalmichthys nobilis while, in Cyprinus carpio it was (60-76%) at water temperature range 22-28 °C respectively.  Degree-hours to spawning were calculated in Hypophthalmichthys nobilis (238.2±1.46-246.4±1) while in Cyprinus carpio it was (215.6±1.3- 226.8±1.28) respectively. Hatching rate of Hypophthalmichthys nobilis was calculated as (52-70 %), while in Cyprinus carpio it was (56 -71 %) and degree-hours to hatching was calculated as (748-784) and (682-702) respectively at water temperature range 22-28 °C respectively. Overall, the rates of fertilization and hatching increases with the increase of water temperature up to limit. These findings can be used to calculate spawning probabilities to enable future spawning predictions for the Hypophthalmichthys nobilis and Cyprinus carpio.