@ARTICLE{Khanjani, author = {Khanjani, Mohammad Hossein and Ghaedi, Gholamreza and }, title = {Evaluation of Fertilization Indices and Stress Response of Rainbow Trout Oncorhynchus mykiss (Walbaum, 1792) in Different Temperatures}, volume = {10}, number = {40}, abstract ={Abstract Temperature is one of the important factors influencing the growth and reproduction of aquatic animals. In this research, the effect of temperature on fertilization indices and stress response of rainbow trout was investigated. Two treatments of temperature, 14.5 and 17.2°C in three replications were considered. Rainbow trout eggs (average weight of 81.30 ± 1.91 mg) with a density of 5000 eggs were stocked per each trough and were exposed to different temperatures until hatching stage. According to the results, it was found that the duration of eyed and hatching stages was shortened with increasing the temperature, and also the percentage of hatching and active swimming decreased. The values of 32.66% and 30% were obtained for hatching and active larvae, respectively, at 17.2 °C, which showed significant difference with another treatment. Responses to the stress of temperature in the early stages of the egg were not noticeable, but the effect of stress on embryos grown at various temperatures caused differences in the response of cortisol to stress at the hatchery stage, which led to an increase in the cortisol level at hatching compared to eyed-stage. When the fish are exposed to stress in the embryonic period, the delayed response of cortisol to stress does not occur immediately after hatching. Finally, the results indicate that the hypothalamus-pituitary- Inter‎renal (HPI) axis is activated at the hatching stage and responds to environmental stresses (as temperature). }, URL = {http://joc.inio.ac.ir/article-1-1529-en.html}, eprint = {http://joc.inio.ac.ir/article-1-1529-en.pdf}, journal = {Journal of Oceanography}, doi = {10.52547/joc.10.40.45}, year = {2020} }