Farmers urged to explore oyster pearl culture
Source: Chronicle News Service / Sagolsem Bigyan
Imphal, December 05 2022:
Pearl culture through oyster farming can be taken up as a viable farming option in the state but it will need support from the authority concerned in order to encourage farmers to foray into this new branch of farming, said Central Agricultural University (CAU) Imphal deputy director of instruction Dr Yumnam Bedajit.
Speaking to The People's Chronicle, Dr Bedajit explained that pearl is formed in the mantle of oyster and similar hard shell bi-valves Mollusca like mussels (Kon-greng).
China is the largest producer of pearls in the world with an annual production of 1500 metric tonnes.
Several countries are also trying to increase their pearl production through different techniques.
He said that water condition for pearl culture is somewhat similar to fish farming and as such, farmers of the state can easily switch to this.
However, it is a relatively new area where no farmers in the state have set their feet yet, and as such it is imperative for the government authorities to extend necessary support to the farmers to encourage them, he said.
Pearl is formed by small crystalline layers of calcium carbonate.
They can be categorised into three types - natural, cultured and artificial pearl.
Natural pearl is rare and it requires shucking (opening) of large number oysters or mussels to find a few.
As such, natural pearl commands high price.
In nature, pearl oysters produce pearls by covering a minute invasive object with nacre.
The irritating object is covered with enough layers of nacre to become a pearl.
The many different types, colours and shapes of pearls depend on the natural pigment of the nacre, and the shape of the original irritant.
Pearl farmers can culture a pearl by placing a nucleus, usually a piece of polished mussel shell, inside the oyster.
The pearl can be harvested after a period of six months or more of plaping the nucleus.
Most of the pearls in the market are cultured pearls while artificial pearls are cheap and used in making decorative items.
Pearl is known for its glistening and lustre looks.
The unique lustre of pearls depends upon the reflection, refraction, and diffraction of light from the translucent layers.
The thinner and more numerous the layers in the pearl the finer the lustre, he explained.
Pearls, especially cultured freshwater pearls, can be dyed with different colours.
The most valuable pearls have a metallic, highly reflective lustre.
They can easily dissolve even in weak acid.
Non-freshwater oysters can be found in hot and cold climate as well.
Cultured pearls can be easily identified through X-ray imaging as the nucleus placed inside the oyster can be visible in the X-ray.
However, natural pearl only shows the calcium carbonate layers in X-ray.
They also can be differentiated by using microscope.
Another easy method to identify natural and cultured pearl is to rub two pearls.
Upon rubbing, natural pearls maintain its smooth texture while the cultured pearls will start showing rough surface, Dr Bedajit added.
(This article has been published under Media Fellowship Programme on Scientific Journalism sponsored by Public Relation and Media Management (PRMM) Cell of the Central Agricultural University (CAU) Imphal.
For further information related with this article, please contact Dr Indira Thounaojam, Information and Publicity Officer, PRMM Cell, CAU through email id: prmmcell@ gmail.com .
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