To study the effect of primary diets on the growth of red claw crayfish and provide guidance, three experiments were carried out in this study. The results of Experiment‐I showed: (a) The juveniles with part of yolk sac just disappeared could feed on Artemia larvae, but those with a whole yolk sac could not. The survival and growth rates of the juveniles fed with Artemia were higher than those not fed. (b) There were two eating modes for juveniles. When fed on small food, the juvenile would clamp the food, when fed on large food, the juvenile would hold the food in its arms, then grasped a small piece of food and nibble it. The results of Experiment‐II showed: (a) The survival and growth rates of juveniles fed with Artemia were higher than those fed with the formula feed. (b) The survival rate and body weight were higher when fed twice a day than once a day. The results of Experiment‐III showed: The survival, growth rates, activities of trypsin of group #2 and group #5 were higher than those of other groups. In conclusion, we came to a conclusion that (a) The primary diet should be offered and available in the water environment immediately when the yolk sac was disappearing. (b) Formula feed should be designed to be easily clamped and stable in water. (c) It was necessary to feed the juveniles twice a day. (d) The primary diet with 85% formula feed +14% Artemia +1% spirulina powder could be applied in future seedling production.

To solve the problems involved in the mass artificial incubation of redclaw crayfish eggs, we developed a recirculating mechanical pulling device to explore the technology of artificial incubation, including the egg stages, egg densities, attachments and incubator sizes. The eggs were separated and sterilized with 3000 ppm formaldehyde, and the water temperature was 28–29°C. The results were obtained: (1) the hatching rates or survival rates of the groups with 7 pairs of appendages and well‐formed eye pigments were significantly higher than those of the egg‐nauplius group; (2) the hatching rates of eggs incubated at densities of 300 eggs/incubator box were significantly higher than those of eggs incubated at 700 eggs/incubator box. The survival rates of eggs incubated at densities of 300 or 500 eggs/incubator box were significantly higher than those for eggs incubated at 700 eggs/incubator box; (3) the survival rates of the group whose incubator received a sponge attachment were significantly higher than those of the group without a sponge attachment; (4) the survival rates of the group with 2.5‐ or 3‐cm width of the upper end of boxes were significantly higher than those of the group with 4 cm; and (5) the eggs with 7 pairs of appendages or well‐formed eye pigments were selected, with a density of 300–500 eggs/incubator box, and the box was 2.5‐cm wide at the upper end. After hatching, sponge attachments were inserted. The hatching rate and survival rate were 85.34% and 61.31%, and a total of 240,031 specific pathogen‐free seedlings were cultivated.

Artificial incubation is an effective way to increase the supply of red claw crayfish seed. In order to explore the effects of nitrite, ammonia nitrogen and pH on the eggs and nitrite on juvenile during in artificial incubation, four experiments were carried out. The results of Experiment I showed: (1) the hatching rate was less affected by nitrite, while the survival rate was greatly affected by nitrite. There were significant differences among the groups. (2) The analysis of the cubic regression equation showed a downward trend with increasing nitrite concentration. The results of Experiment II showed that the hatching rate was less affected by ammonia nitrogen, while the survival rate was affected by ammonia nitrogen, the suitable value range was 0–0.6 mg/L. The results of Experiment III showed that the incubation rate was less affected by pH, while the survival rate was affected by pH. The survival rate of the pH 7.7 or pH 8.4 group was significantly higher than that of the other three groups. The results of Experiment IV showed: (1) the LC50 of nitrite for 96 h was 11.43 mg/L, and the safe SC concentration was 1.14 mg/L. (2) The survival and growth rate, antioxidant capacity and immune‐related indexes of juveniles in the 0.023 mg/L nitrite concentration group were the lowest. In summary, to obtain a stable and high production of red claw crayfish by artificial incubation, it was necessary to keep the concentration of nitrite, ammonia nitrogen and pH value in the appropriate range.