Abstract: To explore the feasibility of large-scale cultivation of rotifer Brachionus plicatilis under low salinity, we investigated life history characteristics of B. plicatilis under salinity-23 and salinity-6 and fed with Chlorella vulgaris at 1.0×10⁴, 1.0×10⁵, 1.0×10⁶, 1.0×10⁷and 1.0×10⁸ cells·mL^-1 by single culture method. The results showed that the reproductive duration, average life span, spawning quantity, life expectancy at hatching (e₀), net reproductive rate (R₀), generation time (T), and intrinsic rate of population increase (r_m) of B. plicatilis in both two salinities increased at first and then decreased with increasing feed densities (P<0.05). The duration of juvenile B. plicatilis under salinity-6 under three food densities of 1.0×10⁶, 1.0×10⁷ and 1.0×10⁸ cells·mL^-1 was smaller than that under food densities of 1.0×10⁴ and 1.0×10⁵ cells·mL^-1 (P<0.05). The duration of juvenile B. plicatilis under salinity-23 under food densities of 1.0×10⁶ and 1.0×10⁷ cells·mL^-1 was smaller than that under food densities of 1.0×10⁴, 1.0×10⁵ and 1.0×10⁸ cells·mL^-1 (P<0.05). The R₀ and r_m of B. plicatilis under salinity-6 were lower than those under salinity-23 in food density of 1.0×10⁴ cells·mL^-1. The e⁰ of B. plicatilis under salinity-6 was significantly higher than that under salinity-23 in food density of 1.0×10⁵ cells·mL^-1. When food density was above 1.0×10⁶ cells·mL^-1, the oviposition quantity, R₀ and r_m of B. plicatilis under salinity6 were significantly higher than those under salinity-23. Our results indicated that B. plicatilis under salinity-23 can gradually acclimate to the environment under salinity-6, due to its freshwater origin. The reproductive rate of B. plicatilis under salinity-6 is higher than that under salinity-23 under food density of above 1.0×10⁶ cells·mL^-1. It is feasible for large-scale cultivation of rotifer B. plicatilis under low salinity.

Key words: Brachionus plicatilis, Chlorella vulgaris, food density, low salt acclimation, life history characteristics.