The Basic Methods of Pearl Farming: A Layman's Manual - CTSA

Basic Methods of Pearl Farmingtough tissue called the “pearl sac.” The inner lining of the pearl sac contains the epithelial cells, whichcontinue secreting nacre onto the nucleus. As the layers of nacre accumulate, a pearl is formed (Figure17).Figure 17. Nacre is formed by the epithelial cells of the mantle tissue. The upper diagram shows a natural irritant or aplastic mabe form being covered progressively with layers of nacre deposited by these cells. In the case of a culturedpearl, this process is imitated. The transplanted piece of mantle tissue contains the nacre-producing epithelial cells.The small piece of tissue grows around the nucleus with the epithelial cells forming the inner layer of the pearl sac (fromWada 1973).The seeding technician will then take the pearl oysters selected for grafting and open them slightlywider. These are placed in a special clamp. After examination, some of these will be rejected as tooold, too small or simply unsuitable for seeding. In most cases, the size and shape of the gonad willdetermine whether the pearl oyster is grafted or not. This is based on the judgment of the graftingtechnician and is learned after years of practice.The technician makes a small cut in the gonad of the pearl oyster. The mantle graft is inserted into thegonad first, followed by the nucleus. The size of the nucleus used depends on the size of the pearloyster and the condition of the gonad. Generally nuclei range in size from 0.3 in (7 mm) to 1.56 in (14mm), with the smaller sizes being most commonly used the first time an animal is grafted. A smallpiece of the donor mantle tissue is inserted last. The pearl oyster is then allowed to close, placed on achaplet or in a tray and returned to the water.Page 54