Optimizing rainbow trout (Oncorhynchus mykiss) Breeding: An assessment of age and performance relationship in nepalese hatcheries

Abstract

The study was conducted to determine the effect of female age on the breeding performance of Rainbow trout at Rainbow Trout Fishery Research Station, Dhunche, from Poush 2079 to Chaitra 2079. The study was carried out in a Completely Randomized Design (CRD) with 5 replications, and each replication consists of 3 treatments of different age groups, viz., 1+ female, 2+ female, and 3+ female. Breeding performance parameters, viz., absolute fecundity, relative fecundity, egg diameter, fertilization rate, hatching rate, egg incubation period, full yolk sac absorption days, alevin to swimmer stage survivability weight, length of first feeding fry, and their production cost, were economically analyzed. Among the treatments, 3+ females exhibited significantly higher absolute fecundity (2165±90.800), egg diameter (4.20±0.174 mm), egg hatching rate (69.48±2.401%), alevin to swimmer stage survivability (97.60±0.602), weight of the first feeding fry (132.600±4.790 mg), and length of the feeding fry (2.488±0.054 cm). Similarly, 1+ females recorded the significantly highest relative fecundity (3207±52.600), egg incubation period (45.60±1.445), and full yolk sac absorption days (74.80±1.433). In terms of economic analysis, 3+ females reported the highest net profit, while the best BC ratio was observed among 2+ females.