This document summarizes information about pearls and pearl oysters. It discusses how pearls are formed naturally within pearl oysters in response to irritants, and how Mikimoto first pioneered cultured pearl production in 1893 by manually inserting irritants. It also provides details on the taxonomy of pearl oysters, their distribution, pearl formation process, protocols for marine pearl culture, and the economic importance of the pearl industry.

1. Presented by :
SYED ASSIM HAQ
Roll No. 2015 ZYM-33
M.Sc. Zoology(F)
Fishery Science And Aquaculture

2. INTRODUCTION
 Pearls are unique as the only gems produced by a
living organism.
 These structures are secreted by the mantle (i.e.,
the skin) of pearl oysters in response to irritations
caused by stimuli such as sand grains, molluscs
eggs, parasites, detritus, and other foreign
particles.

3. HISTORY
 Kokichi Mikimoto, in 1893 created the world's
first cultured pearl by manually introducing an
irritant into an oyster to stimulate it to form a
pearl.

4.  Tokishi Nishikawa and Tatsuhei Mise
independently learned the secret to spherical pearl
production. Their discovery is commonly known as
the "Mise-Nishikawa method".
 In India, in October 1972, the CMFRI started a
pearl culture research project at Tuticorin. Success
came in July 1973 when a perfectly spherical pearl
was produced.

5. PEARL OYSTER

6. TAXONOMY
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Pterioida
Family: Pteriidae
Genus: Pinctada

7. Pinctada maxima
Pinctada margaritifera
Pinctada fucata

8. DISTRIBUTION
•Japan
•China
•Vietnam
•Australia
•Indonesia
•Myanmar
•Philippines
•Tahiti

9. • Shell structure
C.L.= conchiolin layer
P.L.= prismatic layer
N.L.= nacreous layer.
MANTLE AND OYSTER SHELL
Columnar epithelium
Connective tissue
Ciliated epithelium
• Mantle

10. Formation of a blister pearl and a free natural pearl
inside the mantle
Formation of cultured pearl
PEARL FORMATION

11. PROTOCOL FOR MARINE
PEARL CULTURE

12.  Temperature (20 – 25 °C)
 Salinity (above 30 ppt)
 Bottom (Gravelly)
 Depth (Optimum depth at ~ 15m )
 Good phytoplankton production
 Moderate water currents
(I) Environmental conditions for culture:

13. (II) Selection of oysters for operation:
• age: above 1.5-2 years
• Weight > 25 g (40 mm)
• Stage of maturity spent resting stage
• Overall health: Good, free from infections
(III) Narcotization :
• Narcotization of selected oysters by sprinkling menthol in
the sea water.

14. (IV) Preparation of graft tissue:
• 2-3 mm square mantel pieces are
prepared.
(V) Implantation:
• Single implantation in the gonad near the intestinal loop.
• Double implantation-close to hepato-pancreas.

15. (VI) Nursing:
 Implanted oysters are placed in cages.
 Healing of operated tissue takes about 3-4 days.
 Dead oysters are removed.
 Healthy implanted oysters are transferred to culture
cages and suspended at depth of about 2-3 m.

16. • On bottom culture
• Raft culture
Rearing
methods
• Long line culture

17. ECONOMIC IMPORTANCE
 Importance to cultivators
 Sell meat, shells, and mostly pearls.
 Importance to businesses
 provides oysters to restaurant.
 provides pearls for jewelry business.
 provides oyster shells which can be used as
ornamentals.
 Source of employment

18. STATUS OF PEARL PRODUCTION
 The world trade of cultured pearl is reported to
be over 3 billion US $ per year.
 India is one of the major importers of pearls
importing pearls worth US $ 4 million every year.
 China is the world's largest producer of freshwater
pearls, producing more than 1,500 metric tons per
year.

19. • South sea cultured pearls
• Black cultured pearls
• Akoya cultured pearls

20. REFERANCE
 www.fao.org/docrep/field/003/AB726E/AB726E00.ht
m#TOC
 THE PEARL OYSTER , Paul Southgate and John Lucas.
 Wikipedia
 www.sustainablepearls.org/pearls/global-pearl-
industry/
 Economic zoology by R.C.SOBTI.