The effect of different level of magnesium sulfate on hatching of cyst and survival and growth of Atremia franciscana

Iran has different populations of Artemia that live in different climates and ecological conditions. Physicochemical conditions of lakes and lagoons have intensified the allopatric Artemia speciation. The aim of this study was to investigate the effect of one of the ions in these climates so that Artemia can be cultivated semi-naturally in some wetlands of Golestan province.

To do this, the effect of four treatments (10, 16, 33, and 50%) of magnesium sulfate instead of other salts on cyst and growth parameters of Artemia franciscana was studied.

There was a significant difference between the experimental groups in the Artemia growth index (P <0.05). Maximum and minimum body lengths were observed in the control and 50% magnesium sulfate groups, respectively. Also, 33 % magnesium sulfate treatment showed a significant decrease in growth rate compared to the control treatment (p <0.05) but did not show a significant difference with 50% magnesium sulfate treatment (P <0.05). At low concentrations of magnesium sulfate growth rate insignificantly decreased in Artemia compared to control treatment. The highest and the lowest survival percentage were observed in control and 50% magnesium sulfate, respectively. On the 15th day, the maximum and minimum survival rate was 83 % and 46% in control and 50% magnesium sulfate treatment, respectively. The highest hatching percentage was observed in the control treatment and the lowest was observed in the 50% magnesium sulfate treatment. Increasing magnesium sulfate concentration significantly decreased the number of nauplii but increased the number of non-hatched cysts (P <0.05). Moreover, the highest number of umbrella stages of Artemia was observed in the treatment with 50% magnesium sulfate. Maximum and minimum hatch efficiency were insignificantly observed in control and 50% magnesium sulfate treatments, respectively. The highest mortality of nauplii was significantly observed in the treatment with maximum magnesium sulfate.

The results of this study showed that magnesium sulfate in high-level amounts limits the hatching and growth of Artemia which should not be introduced to such climates.