The effect of ecogheomorphologic variations on water physiochemical parameters (Zyarat river- Golestan province)

Subject Areas : New Technologies in Aquaculture Development

Received: 2020-01-11 Accepted : 2020-01-11 Published : 2018-02-20

Keywords: Keywords: Golestan province, Water physiochemical parameters, Zyarat river,

Abstract :

Abstract[1] The aim of this research is study the effects of freezing at -20 ◦C after hydration and dehydration on the hatching, survival percentage and growth of Artemia urmiana cysts. Experiments were carried out in three treatments. In first treatment, hatching was done after one hydration and dehydration cycle with standard method. In second treatment, hatching was done after one hydration and dehydration cycle and then one week freezing at -20 ◦C temperature. In third treatment, hatching was done after one hydration and dehydration cycle and then one month freezing at -20 ◦C temperature. Standard hatching was done without any other treatment in Control group. Hatching percentage was determined with three replicates for each treatment by standard method. Survival and growth was measured and compared on days 8, 11, 15, 20 and 25 of growth. Results indicated the cyst hatching percentage increased regularly by increasing freezing time (one month freezing), even though hatching percentage was higher in control group. The most survival percentage was observed in 11th day of third treatment. Highest growth was in 15 to 25th day of third treatment (P<0.05). To sum up, against some other species, hydration/dehydration and freezing is not necessary in Artemia urmiana and performing it decreases hatching percentage. * Corresponding author; [e-mail]