Growth performance of rainbow trout (Oncorhynchus mykiss) with respect to nutritional factors in north Iran (Haraz River)

Monthly samples of six fish farms from January ۲۰۱۰ to December ۲۰۱۰ in the northern Iran, Haraz River, were used to determine relationship between chemical parameters of main water, inlet and outlet and their effects on fish growth and production. Results revealed that concentration of nutrients in outlet was more than that of inlet of farms and statistical analysis showed that there were significant differences between stations (p۰.۰۵) in different months Correlation between daily growth, SGR, FCR, production and chemical parameters of water were analyzed by Pearson Correlation. The results revealed negative correlation (α= ۰.۰۱) between nitrite and daily growth (P=۰.۰۰۴, Pearson Correlation=-۰.۲۴), ammonium and SGR (P=۰.۰۰۰۱, Pearson Correlation=-۰.۲۷۲), although there were no correlation for FCR, and nutritional parameters (p>۰.۰۵).