A study on primary diets for juveniles of red claw crayfish Cherax quadricarinatus

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.