The study of different levels of hardness and different rations of Ca and Mg water hardness on cyst hatching and larval quality of the fairy shrimp: Phallocryptus spinosa

Anostracas have a wide distribution in the world, Considering the appropriate size and relatively desirable nutritional value, they have a very good potential as a live food for different species of aquatic animals. The biological function of all aquatic organisms is directly or indirectly affected by the physico-chemical properties of water. For living organisms in aquatic ecosystems, non-living factors such as temperature, water hardness and pH are among the most important factors in the success of growth and reproduction. The aim of this study was to investigate the effects of various levels of hardness and various ratios of calcium and magnesium on water hardness on hatching performance and the quality of Phallocryptus spinosa larvae. In this experiment, three hardness levels of 200, 500, 1000 mg / L with calcium and magnesium ratios of 100: 0, 80:20, 50:50, 20:80 and 0: 100 were compared to the control treatment with 110 mg / liter hardness. Reproductive and larval quality assessment indices included hatch rate, larval size and mortality rate of larvae. Experiments on the effects of different levels of hardness and various ratios of calcium and magnesium on the Phallocryptus spinosa at a significant level of 0.005 showed that the best rate of hatching of this species was 500 mg / L, and the best ratio of calcium and magnesium was also 50:50 ratio.