10-40% Potential Mortality Rate

Following the delicate grafting process, the pearl oyster is put back into the lagoon for the graft to grow for a period of 18-24 months.

The implanted graft grows to form a pearl-sac around the nucleus, enveloping it with a thin layer of a secreted nacreous material.

This growth period is critical to the oyster as well as the pearl farmer. The mortality rate following the grafting operation is anywhere from 10-40%. Or the oyster may simply spit out the foreign nucleus, rejecting it.

Finally, the grafted oyster may experience severe disturbances to its metabolism, influencing the quality of the eventual pearl that is produced.But if the grafted oyster expels the nucleus, the pearl oyster can be overgrafted. This means a new nucleus is inserted.

Or the pearl-sac may be left to secrete what the Japanese have named a keshi pearl, which has the same colors as pearls from Tahiti and is made up entirely of pearly layers.

Photo Source: "Pearls from the myths to modern pearl culture", P. Salomon and M. Roudnitska