What Is Pearl Farming?
Cultured pearls are grown on what are known as pearl farms. Several thousand oysters are nucleated and then cared for during the 2-5 years required for a pearl to grow and develop. Like any other form of farming, pearl farming can be as dependent on luck as it is on skill. An entire bed of oysters can be completely devastated by unpredictable and uncontrollable factors, such as water pollution, severe storms, excessive heat or cold, disease and many other natural and man-made phenomena. Although pearl farmers attempt to control as many of these variables as possible, pearl farming can indeed be a risky business!
The Process Of Nucleation In Pearl Farming
The process of nucleation is a surgical procedure, whereby a foreign object is implanted into the oyster. This object causes irritation, which the oyster counteracts by secreting nacre to surround the object; this produces the pearl.
How Oysters Are Raised In Pearl Farming
The larvae are allowed to float freely in the water, under controlled conditions, until they are a few weeks old. In the wild, the larvae would then attach themselves to a rock or similar object, so the farmers provide “collectors” for this purpose. Over a period of a few months, the larvae develop into baby oysters. They are generally then moved into a separate "nursery" area of the farm. Here they are tended for around 1-2 years, until they have grown sufficiently large to be nucleated.
Saltwater Nucleation In Pearl Farming
Two basic methods of nucleation are used. Saltwater oysters are generally nucleated using a "bead", prepared from mother-of-pearl. First, the bead is surrounded by a small piece of mantle tissue taken from a donor oyster. The bead and tissue are then implanted into the oyster's gonad. The bead serves as a mold, or nucleus, around which the pearl develops. The resulting pearl will contain the bead at its center and will tend to develop in the same general shape as the original bead. The bead can be detected in the final pearl by x-rays.
Freshwater Mussel Grafting In Pearl Farming
Freshwater mussels are generally grafted using a piece of mantle tissue only, without a bead. This small piece of mantle tissue is placed into an incision in the host mussel's mantle instead of the gonad. Both sides of the valve can accept grafts, and an average freshwater mussel will produce 24 to 32 pearls per culturing cycle.
The Pearl Is Now Allowed To Grow
After nucleating, the oysters are given a few weeks to recover from the surgery. During this time, some of the oysters may reject and expel the implanted nuclei; others may become sick or even die. Most, however, will fully recover. The oysters are then placed in cages or nets and moved into the oyster bed, where they will be tended as the pearls develop. Depending on the type of oyster, this process can require anywhere from a few additional months to several more years!
Finally, The Pearls Are Harvested
After the pearls have been allowed to develop fully, they must be harvested. After the pearls are extracted from the oysters, they are washed, dried, and sorted into general categories. Sometimes, the pearls are polished by tumbling in salt and water. The pearls are then sold to jewelers, manufacturers, and pearl dealers.