author(s)
NN Pandey, Bipin Kumar Vishwakarma, Sheetal Sharma and Santosh Kumar

abstract
Due to extra genetic material, triploid fish remain more heterozygous and suppose to be useful for increasing growth. A field study of 6 months was conducted to evaluate the growth performance of the diploid and triploid Oncorhynchus mykiss, which is one of the candidate fish for coldwater aquaculture in Himalayan region. Triploids were produced by pressure shock after post fertilization of eggs. The control group of diploids was observed for final body length and weight from the range of 32.9±0.83mm to 33.0±0.84 mm (0.89±0.083g to 0.91±0.081g), while treated triploids were observed as 42.8±0.79 to 43.25±0.77 mm (1.05±0.033 to 1.07±0.033 g). Observed data showed a significant difference (p<0.05) with 17.58% higher growth in triploids over diploids. Survival rate was in the range of 94-96% without any significant difference in both the groups. Study showed feasibility for achieving better growth of this fish in captive rearing with triploids.