Research Article: Artificial breeding success, incubation period, and fecundity of rainbow trout, Oncorhynchus mykiss (Kamloops Strain), in Jaghour trout hatchery, Chitral

Rainbow trout (Oncorhynchus mykiss; Kamloops strain), were introduced to Khyber Pakhtunkhwa in ۱۹۲۸ and are now successfully farming in the Malakand and Hazara divisions due to the region's favorable cold-water conditions. Our study investigated the artificial breeding success, incubation period, and fecundity of rainbow trout at Jaghour trout hatchery in the district Chitral. A total of ۴,۳۱۱ eggs were harvested from four females with a combined body weight of ۱.۲۶۴ kg. The eggs were fertilized and incubated in spring water at temperatures ranging from ۱۲.۶ to ۱۳.۳°C. The survival and mortality rates from fertilization to hatching were approximately ۷۹% and ۲۱%, respectively. The eyed stage commenced at around ۱۵۵±۰۵ degree days (D°), with hatching occurring at approximately ۳۰۵±۰۵ D°. The incubation period spanned from ۳۰۵±۰۵ to ۳۴۹±۰۵ D°. Furthermore, the study explores female fecundity, revealing a range of ۱.۸۷ to ۳.۴۲ eggs per gram of body weight (n=۱۵). The size of green ova increased by ۱.۰۲% to ۸.۶۰% during water hardening at ۹°C for ۱.۵ h (n=۴۶). Our study provides valuable insights into the incubation period of Rainbow trout, highlighting the survival and mortality rates of fertilized eggs in spring water. This information can assist local hatchery managers in estimating seed production from known brood stock.

کلیدواژه ها:

Spawning period ، Stripping ، Gamete quality parameters ، Water hardening ، Eyed eggs