Dear Selcuk,
In the Forum Pearl Resources you will a comprehensive study from an Indian research group working with various pinctada species including pinctada radiata. The thread with the link to the study is called Everything You Ever Wanted To Know About Pearl Culturing (
http://www.pearl-guide.com/forum/showthread.php?t=376).
I hope this will be helpful to you,
Zeide G. Erskine