In this study the effect of different salinities on growth, biomass and pigments of Chlorophyll a and Carotenoid were tested to determine an appropriate salinity to produce maximum growth, biomass and carotenoids of microalgae (N.oculat).Therefore, the 2-liter flask contains microalga under different levels of salinities (20, 25, 32, 35, 50 ppt), and under laboratory conditions( temperature 25-22 ° C, PH. 8, and light period of 12 h light and 12 h darkness) were cultured for 14 days. The results of present study indicate that The maximum growth of microalgae (72.63×106 cell ml–1) and the maximum specific growth rate of microalgae (0.33 d⁻1) included in treatments with salinity of 25 and 30 ppt, that had a significant difference with the other treatments (p<0.05). The maximum dry weight (0.022 g/lit) and amount of chlorophyll a (3.92 mg lit) was recorded in treatments with salinity of 30 ppt and shows significant difference with the other treatment (p<0.05). The Minimum amount of carotenoids (0.41 mg lit) was related to treatment with salinity of 50 ppt. shows a significant difference with other treatments (p<0.05). According to the results we can say that microalgae resistant to high salinity and a wide range of salinity has the ability to grow and produce carotenoids
