Abstract: In this study, the effects of salinity and temperature on the growth of A. nauplii were investigated. The survival rate, body length and immune changes of A. nauplii were studied by hydrostatic experiment. In the salinity mutation experiment, except for the salinity mutation to 45, the survival rate and average growth rate of the other salinity mutation groups were significantly different from those of the control group. The lowest survival rate of the salinity 5 mutation group was 0, and the lowest average growth rate of the salinity 100 mutation group was 46.12 μm/d. The activities of alkaline phosphatase（AKP）, acid phosphatase（ACP）and superoxide dismutase（SOD）in A. nauplii increased first and then decreased with the increase of salinity mutation. The activities of AKP and SOD in the salinity 5 mutation group decreased the most compared with the control group, which were 4.78 J/gprot and 0.70 U/mgprot, respectively. The activity of ACP in the salinity 100 mutation group decreased the most, which was 7.40 J/gprot. It was concluded that the mutation to low salinity had a great impact on its enzyme activity. In the temperature mutation experiment, the average growth rate at 30 ℃ was 102.28 μm/d, and the survival rate was 77.78%. There was no significant difference between the group and the control group, and there were significant differences between the other temperature mutations and the control group. A. nauplii was more adaptable to low temperature mutations than to high temperature mutations, but the growth was slower; The activity of AKP, ACP and SOD in A. nauplii increased first and then decreased with the increase of temperature mutation range. The AKP, ACP and SOD in 40℃ group decreased the most compared with the control group, which were 9.22 J/gprot, 8.76 J/gprot and 1.50 U/mgprot, respectively. It was concluded that the mutation to high temperature had a great influence on the enzyme activity. The results showed that salinity and temperature mutations had significant effects on the survival rate, body length growth and immunity of Artemia nauplii in Bohai Bay. The purpose of this study was to find out the range of salinity mutation and temperature mutation that can be well adapted to the survival, growth and immune enzyme activity of Artemia nauplii, so as to provide important basis and favorable support for the artificial cultivation of Artemia nauplii in the future.

Key words: Artemia nauplii, salinity mutation, survival rate, body length, immune enzyme activity