Pearl Culture: A remarkable achievement of Cotton University

Silpi Sikha Borah

(The writer is a doctoral scholar and an ex-Cottonian from the Department of Zoology.)

The Zoology Department of Cotton University, under the leadership of Dr Akalesh Kumar Verma, has been actively engaged in harvesting pearls from freshwater bivalve molluscs (Unio mussel) for the very first time in Assam. This initiative combines scientific innovation with traditional knowledge, with the potential to establish pearl culture as a sustainable livelihood option not only in Assam but across the entire Northeast region. Pearl is a hard, lustrous substance that forms inside the living tissues of bivalve molluscs. Often referred to as the “Queen of Gems”, pearls have long been regarded as a symbol of prestige and elegance throughout history. They are composed of 82–86% calcium carbonate, 10–14% conchiolin, and 2–4% water. Pearls occur in a variety of colours, such as white, black, yellow, blue, red, and green. Kokichi Mikimoto (1858–1954), widely recognized as the “Father of Pearl”, successfully pioneered pearl farming in Japan and established the global pearl industry. In India, the first technological breakthrough in pearl culture was achieved in 1973 by the Central Marine Fisheries Research Institute (CMFRI) at Tuticorin, Tamil Nadu. Hyderabad later emerged as the country’s major pearl trading hub, earning it the name “City of Pearls”.

Pearl culture has immense economic potential, as it is considered one of the most valuable aquaculture industries worldwide, generating billions of dollars annually. Currently, the leading pearl-producing countries include China, Japan, Australia, Indonesia, French Polynesia, the Cook Islands, the Philippines, India, Sri Lanka, Myanmar, Malaysia, Thailand, and Mexico. Global pearl production is estimated to be around 78 tonnes, with a market value of approximately USD 1,042 million. India imports pearls worth nearly USD 10 million annually. However, India’s effective pearl production capacity remains relatively low compared to other leading countries, preventing the nation from making a strong presence in the global pearl trade. In July 2020, drawing attention to successful examples of pearl farmers in Bihar, the Hon’ble Prime Minister Shri Narendra Modi emphasized the immense future potential of pearl farming in India. In the northeastern region, despite favourable conditions, pearl culture remains underdeveloped due to a lack of scientific techniques and adequate knowledge among farmers.

Pearl Production Process:

(a) Collection and Selection of Mussels

Native species such as Lamellidens marginalis and Lamellidens corrianus are carefully collected from breeding centres established at the university. Selection of healthy, mature mussels is carried out based on parameters like shell length, weight, and gonadal maturity.

(b) Surgical Nucleation

This is a critical step where a nucleus (commonly a shell bead or mantle tissue piece) is implanted into the gonadal tissues of the mussel. The procedure is performed under controlled and sterile conditions.

Post-surgery, mussels are kept for 7–10 days in laboratory tanks with regulated water quality to recover.

(c) Rearing and Maintenance

After recovery, mussels are reared in cement tanks, earthen ponds, or open-water cages. Key water quality parameters such as pH, temperature, oxygen, and alkalinity are monitored regularly. Mussels are fed with phytoplankton, zooplankton, and organic detritus to ensure proper growth.

(d) Harvesting and Evaluation

After 12–18 months, mussels are carefully harvested to collect pearls of different shapes and sizes. For high-quality spherical pearls, a longer duration of 24–36 months is often required.

Pearl culture thus emerges as a sustainable model for economic self-reliance. With the vision of equipping the younger generation with viable economic opportunities, the Zoology Department of Cotton University has initiated workshops and training programmes at national and international levels to disseminate scientific techniques of pearl farming.

This unique and highly significant effort by Cotton University to foster self-reliance among the youth of Assam deserves wholehearted appreciation and recognition.