from what i heard from some vendors..cant mention who..the reason is due to permits/licenses to import these from other countries are being stopped..i was upset upon hearing this too..but they also told me it should only be a few months..then everything should be back to normal..hopefully
Most are aquacultured...but they still have to be imported...outside of maybe Hawaii, I don't know of any stateside Tridacna aquaculture. As for crocea's, for along time that seemed to be the only clam easily available...but they also seem to be much easier to keep than in years past.