Photo credit: David Kawahigashi (Thailand – David Kawahigashi – Vannamei101)
Review: Abdel Rahman El Gamal (Founder of the website)
The inserted photo is for a batch of post-larvae 12 (PL12) of whiteleg shrimp (Litopenaeus vannamei) that are ready for stocking in grow-out facilities. From hatching, it takes about 21 days to reach the PL12.
The stages younger than PL12 do not have sufficient osmoregulatory ability to allow them to acclimate to low salinity water. Therefore, postlarvae held to PL12 in nursery facilities generally show more advanced gill development, which is important to acclimation to farm conditions and hence higher rates of survival which might average >60 percent assuming good environmental conditions.
Because most farming operations for L. vannamei are not furnished with nurseries, they receive the PL12 from shrimp hatcheries and introduce them directly in the grow-out ponds.