Deqing, a county in Zhejiang Province, is known as a "land of water" for its intricate network of waterways, canals and lakes. This abundance of water provides a strong foundation for freshwater aquaculture, fostering the production of lustrous pearls. For centuries, the people of Deqing have practiced a unique freshwater pearl composite farming system centered on "fish-mussel co-culture."

In this integrated aquaculture model, fish feed on aquatic plants, mussels absorb nutrients from fish waste and purify water, and pearls are cultivated within the mussels. The system simultaneously enhances water quality, restores ecological balance and generates dual economic value—from both fishery yields and premium pearl production.

This model, officially called the Zhejiang Deqing Freshwater Pearl Mussel Composite Fishery System, or simply the Deqing Pearl System, received global recognition on May 21, as it was added to the United Nations Food and Agriculture Organization's (FAO) list of Globally Important Agricultural Heritage Systems (GIAHS) for 2025. Joining the Deqing Pearl System were two other Chinese systems: an ancient pear orchard system in Gansu Province, northwest China, and a white tea culture system in Fujian Province, southeast China. With these latest additions, China now has 25 GIAHS, the highest number in the world.

Launched by the FAO in 2002, the GIAHS program assists farming communities in safeguarding traditional agricultural systems and their associated landscapes, agricultural biodiversity, knowledge systems and cultures.

"As China's first GIAHS project in aquaculture, the Deqing Pearl System builds a new bridge for Chinese traditional agricultural wisdom to reach the global stage and has exemplary significance," Min Qingwen, head of the expert committee on the GIAHS under the Ministry of Agriculture and Rural Affairs, told Global Times newspaper.

He added that the successful application was just the beginning and that Deqing will continue to explore pearl culture and promote its global influence.

An arduous journey

Artificial freshwater pearl cultivation in Deqing dates back to the Southern Song Dynasty (1127-1279). It was during that period that Ye Jinyang, a resident of Huzhou Prefecture (modern-day Huzhou City in Zhejiang, to which Deqing belongs), pioneered the technique.

Using the locally-sourced Cristaria plicata (commonly known as the cockcomb pearl mussel), Ye successfully cultivated pearls by implanting nuclei—tiny reliefs made of tin, wood, bone or other materials—between the mussel's shell and mantle tissue. Doing so kickstarted a big transition—from relying solely on natural pearls to mastering controlled cultivation techniques.

However, various factors led to a decline in China's artificial freshwater pearl farming technology in modern times.

The story of the "Chinese Pearl" took a turn in 1967 when Shen Zhirong, a 19-year-old fish farmer from Leidian Town in Deqing, embarked on a long and arduous journey to revive the nation's pearl farming heritage.

Through meticulous observation, Shen discovered that triangle sail mussels (Hyriopsis cumingii) consistently produced pearls of superior quality, boasting a whiter and brighter luster compared with those from other mussel species. This realization led him to focus his efforts on the selective cultivation of these unique mussels.

In the mid-1970s, Shen successfully developed artificial breeding techniques for triangle sail mussels. This achievement laid the foundation for China's large-scale freshwater pearl cultivation industry.

But in the early 2000s, a crisis emerged in Deqing's pearl farming industry. In an attempt to boost pearl production and shorten breeding cycles, some farmers resorted to adding chicken manure, bird droppings and pig manure to the water as food for phytoplankton, resulting in severe water pollution.

Too much nutrients in the water can cause algae blooms, and algae can use up the oxygen in the water, suffocating other life in the water such as fish. Mussels are natural water purifiers, consuming algae and fish waste and absorbing excess nutrients like nitrogen and phosphorus.

Traditionally, Deqing's farmers used fish-mussel co-culture system, under which fish waste fertilizes phytoplankton, which mussels consume while simultaneously cultivating pearls. To reduce pollution, in recent years, Deqing has re-embraced the traditional ecologically friendly fish-mussel co-culture practices and created a comprehensive pearl industry chain, prioritizing the wellbeing of its ecology and people.

Though this ecological approach extends pearl growth cycle to five to six years, compared with the one- to two-year cycle under intensive farming, it does greatly improve water quality.

Deep-processing innovation

While pearls are commonly associated with jewelry, in reality, only a small fraction, approximately 5 percent, of artificially cultured pearls are ultimately selected for jewelry production.

Shen understood that relying solely on jewelry production would hinder the long-term sustainability of pearl farming. Consequently, he began exploring the possibilities of deep pearl processing, seeking to maximize the value of remaining pearl resources through the development of cosmetics and health products. In 1992, Shen founded the Osmun Group, which has since grown into an enterprise encompassing pearl farming, pearl cosmetics, pearl health products, pearl jewelry and pearl-themed cultural tourism.

Today, Deqing's annual deep pearl processing output approaches 100 tons, or about 10 percent of the national total. This accomplishment positions Deqing as the largest freshwater pearl deep-processing base in China. The county's combined annual output value of pearl farming and deep processing exceeds 7 billion yuan ($974 million), and the sector employs nearly 20,000 people, around 4 percent of the county's population.

Committed to preserving this invaluable agricultural heritage, Osmun has invested 200 million yuan ($28 million) in the creation of a pearl culture park in Deqing. Within the park's Osmun Pearl Museum, visitors can immerse themselves in the origin, culture and history of pearls while uncovering the mysteries of traditional ecological farming techniques.

The Xiaoshanyang Freshwater Pearl Ecological Farming Base in Deqing has also become a popular destination for outdoor educational activities.

Here, children can embark on captivating journeys aboard wooden boats, gliding across the shimmering lake, learning about pearl mussels and opening the mussels to reveal their hidden treasures.

Copyedited by Elsbeth van Paridon

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