Utilization of infertile coastal lands in the north Iran and Caspian Sea brackish water for reproduction and rearing of Beluga was the main objective of this study. To do so, 600 Huso huso fingerlings with an average weight of 4829 grams were reared in fiberglass tanks (1.9*1.9*0.53m), amounting to 25 fish per square meter. We used a random statistical design in two trials under similar conditions (feeding rate, stocking density etc.) over a rearing period of 80 days. Brackish water was transferred from the Caspian Sea and used in four tanks (Group I) and freshwater from the Sefidrood River was used in the remaining two tanks. Four replicates were used for experimental tanks and two were used for control tanks. Water flow in both groups was maintained at 0.2 to 0.5 liters per second. Results were analyzed statistically using one-way ANOVA and Duncan test. Mean water temperatures for brackish and freshwater treatments were 22.4±3.7 and 23.1±3/9 degrees centigrade respectively. Results o.....