Reproductive characteristics of Artemia

  Like other creatures in branchipoda class, Artemia can produce dormant embryos known as cysts in the extreme condition. In the dry condition, cysts are inactive and have no growth. At the moment, the embryos are interrupted temporarily. This period is called dormancy state or diapause state. The embryos are active again when environment becomes more favorable. At that time, cysts sink in the drink water and start modification. By virtue of that, in the period of hatch in oceanic water environment, if hatching process occurs in the oceanic water, it is necessary to have a slight aeration around 20 hours in order to cysts evolving into nauplius.  It can be concluded that Artemia female can reproduce via both oviparity and ovoviviparity. 

•    Ovoviviparous reproduction is that eggs are fertilized to grow up into nauplius in the uterus. Then, the mothers will release nauplius into water. 
•    Oviparous reproduction means that fertilized eggs will only develop up to the gastrula stage. At this moment they get surrounded by a thick shell, enter a state of metabolic standstill or dormancy (diapause) and are then released by the female.
Many researches show that dissolved oxygen content, salinity, vibratile amplitude of oxygen content and iron content in food are the key factors affecting the reproduction method of Artemia. In detail, if the environment has high content oxygen, low salinity, short amplitude of oxygen content and food with low concentration of iron, Artemia will tend to produce the younger generation via ovoviviparous reproduction. By contrast, Artemia will carry on the oviparous reproduction (reproducing cysts). However, some other studies illustrate that temperature is another factor affect the reproduction method of Artemia. Each female can make 1.500-2.500 cysts or nauplius 
Source: vietlinh.vn