The document outlines the process and significance of pearl culture, particularly focusing on the cultivation of pearls from freshwater mussels and saltwater pearl oysters. It details the steps involved in pearl farming, from construction of the farm and the collection of oysters to implantation and harvesting, highlighting key factors such as climatic conditions and economic importance. Historical context is also provided, noting Japan's pivotal role in advancing the pearl culturing industry.

1. PEARL CULTURE
DR. C. BEULAH JAYARANI
M.Sc., M.A, M.Ed, M.Phil (Edn), M.Phil (ZOO), NET, Ph.D (Edn)
ASST. PROFESSOR,
LOYOLA COLLEGE OF EDUCATION, CHENNAI - 34

2. INTRODUCTION
Pearl is a white, highly shining globular
found within the shell of an oyster.
Sedentary animals.
First cultured in 1973 in Tuticorin.
Found along the coast of kanyakumari
and in Gulf of kutch.
Genus(Pinctada, Lamellidens).
“Lingha pearl”.
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3. CLASSIFICATION
• Kingdom: Animalia
• Phylum : Mollusca
• Class : Bivalvia
• Order : Ostreida
• Superfamily : Ostreoidea
• Family : Ostreidae
• Genus :Crassostrea
• Species : rhizophorae
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4. ANATOMY OF PEARL OYSTER
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5. PEARL CULTURE
• A cultured pearl is a pearl initiated by a mussel or
oyster farmer under controlled conditions using two
very different groups of bivalve mollusks - the
freshwater river mussels and saltwater pearl oysters
MOLLUSKS
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6. PEARL FORMATION
• A natural pearl (often called an Oriental pearl)
forms when an irritant works its way into a
particular species of oyster, mussel, or clam.
As a defense mechanism, the mollusk
secretes a fluid to coat the irritant such as
sand grains, mollusks eggs, parasites &
other foreign bodies. The oyster or mussel
slowly secretes layers of aragonite and
conchiolin materials that also make up its
shell it goes on until a lustrous pearl is
formed..
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8. HISTORY OF PEARL CULTURE
• The history of Japan's pearl culturing
industry started with Kokichi Mikimoto,
who dreamed of producing gem-
quality pearls using the Akoya oyster. In
1899 he started selling ornaments using
Hanen blisters for the first time and
carved out a new market in which
cultured pearls were handled as jewelry.
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9. IMPLANTATION
• Single implantation in the gonad near the intestinal loop.
• Double implantation close to hepato-pancreases.
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10. STEPS INVOLVED IN PEARL CULTURE
Construction of farm.
Collection of oysters.
Rearing of oysters.
Preparation of the graft tissue.
Insertion of nucleus.
Harvesting of pearl.
Clearing of pearls.
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11. 1. CONSTRUCTION OF PEARL FARM
Construction of a pearl farm includes three steps.
They are,
• Selection of farm site
• Construction of farm
• Well-planned work schedule
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12. CLIMATIC CONDITION FOR THE CULTURE
Temperature – 20 to 25° C
Salinity (above 30 ppt)
Bottom (Gravelly)
Depth (Optimum depth – 15 m)
Good phytoplankton production
Moderate water current
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13. NARCOTIZATION
• Narcotization of selected oysters by sprinkling Menthol in the
sea water
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14. 2. COLLECTION OF OYSTERS
From July to November, the spats are easily
available.
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15. Special type of cages
(84 ×54 × 20 cm)
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16. The divers set out to the bottom of the sea, to collect the oysters.
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17. NURSING
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18. 3.REARING OF OYSTERS
The collected oysters are
The collected oysters are
cleaned and placed in culture
cages.
10-20 days
Stocked and reared in special
type of cage called as rearing
cage.
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19. 4.INSERTION OF NUCLEUS
Following steps are done in
insertion of nucleus
a. Fitness of oyster for operation
b. Insertion of graft tissues
c. Preparation of nucleus
d. Insertion of nucleus
e. Post operation care
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20. A. FITNESS OF OYSTER FOR OPERATION
AGE: 1.5 to 2 years
WEIGHT: 25g (40mm)
STAGE OF MATURITY- spent resting stage
OVER ALL HEALTH: Good & free from infections
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21. b. INSERTION OF GRAFT TISSUE
• The piece of tissue which is
inserted inside the mantle is
called as “Graft tissue”.
• A donor oyster is sacrificed
to obtain mantle.
• 2-3 mm of square mantel
pieces are prepared
• Mantle is needed by the
host oyster to accept the
nucleus.
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22. C. THE NUCLEUS - HEART OF THE PEARL
Any small particle may function as nucleus.
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23. D. INSERTION OF NUCLEUS
STEP 1: oysters are fixed in a desk clamp position of right valve facing
upward.
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24. STEP 2: mantle folds are touched smoothly, followed by incision in
the epithelium of the foot.
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25. STEP 3: in the slender channel, one graft tissue which functions as
the bed for the nucleus.
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26. E. POST OPERATION CARE
Suspended in the floating rafts to a depth of 2 to 3 meters for about 6-7 days to
recover from the shock. This period is called as the recovery period.
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27. 4. HARVESTING OF PEARL
Pearls are harvested after 3 years of the insertion of nucleus from
December to February
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28. 5. CLEARING OF PEARLS
After taking out the pearls from the oyster shell, they are washed,
cleared with soap solution.
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29. COMPOSITION OF PEARL
• Pearl comprises of
Water 2-4%
organic matter 3.5-5.9%
calcium carbonate 90%
Residue 0.1-0.8%
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30. ECONOMIC IMPORTANCE
• 1. Importance to cultivators
Sells meat, shells & mostly pearls
• 2. Importance to businesses
• Provide oysters to restaurant
• Provides pearls for jewellery
• Provides oysters shells can be used as ornamental
• 3. Importance to employment
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31. REFERENCE
“SCIENCE READER”
 Tamil Nadu text book
 NCERT Books
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