China’s pearl industry may be losing its luster, as farmers struggle to adapt to stricter clean water standards.

In 2015, China’s central government released a 10-point action plan to protect groundwater quality and clean up polluted rivers and coasts. Unfortunately for the country’s pearl-growing industry, rigorous enforcement of this plan has left farmers feeling caught in its net. But being forced to adjust to widespread shutdowns of substandard ponds has also prompted some farmers to explore more efficient, more innovative technologies.

The Water Pollution Prevention and Control Action Plan took aim at serious pollution across all industries — including mining, chemicals, and manufacturing — by setting national standards and deadlines for water remediation, and by targeting major river basins, including those of the Yangtze and Yellow rivers.

Pearl cultivation generally involves manmade freshwater lakes that are regularly topped up with sewage to encourage the growth of algae that nourish pearl-producing mussels. China’s return to the international market in the early 1980s transformed the use of pearls within the global jewelry sector.

The freshwater pearl industry now operates on a vast scale in eastern Zhejiang and central Hubei provinces, where ponds cover hundreds of square kilometers. Although reliable statistics are hard to find, Chinese pearl production is thought to have reached between 1,500 and 2,000 tons per year at its peak, and current production is estimated at 600 tons per year.

Most freshwater mussels are cultivated in lakes or manmade ponds two or three meters deep, where they grow for up to five years before being harvested. The ponds are enriched with fermented animal manure and often chemical fertilizers, too, to produce an optimal amount of algae for the mussels to feed on.

The result is pond water that’s loaded with nutrients but lacking oxygen — a phenomenon known as eutrophication. To curb this problem, phytoplankton-consuming carp are added to the ponds. But when badly managed, pearl cultivation can result in excessive eutrophication that stymies biodiversity in the water.

Environmental concerns have only grown over the past decade. In 2007, Hubei province temporarily banned new pearl farming licenses in an effort to clean up its proliferating algal blooms.

Implementation of the 2015 Water Pollution Prevention and Control Action Plan is having a serious impact on the pearl industry, forcing many pearl producers to improve the water quality of their ponds. The plan foresees that by 2020, the quality of over 70 percent of seven key river basins — some close to pearl-farming areas — will be of sufficient quality to provide drinking water, and that the amount of foul water in urban areas will not exceed 10 percent.

The Zhejiang Professional Association of Pearls has said freshwater pearl farming declined from about 25,000 square kilometers to less than 10,000 between 2005 and 2016, and output halved over this same period, from 2,000 to 1,000 tons.

Zhuji, Zhejiang province — the birthplace of pearl production in China — is witnessing the latest wave of closures. Zhuji has become more important as a pearl trading center than a production hub, as industrialization has shifted ponds to more rural areas in the past two decades.

Zhuji’s remaining pearl farmers must adapt to new restrictions. On Feb. 21, Zhuji water conservancy officials announced that pearling would be banned across 6,000 square kilometers encompassing more than 170 farms. To continue trading, the farms’ waters must meet a standard of being “suitable for recreational use” by the end of 2017. Water quality may then rise to a Class B water supply, making it a safe source for drinking.

Officials accept that the remediation of these sites is both costly and complicated for farmers, but also assert that it’s necessary for the industry to thrive in the long term, as well as for compliance with the 2015 plan to control water pollution.

Some pearl farmers and scientists are investigating how greater use of automation in aquaculture could help to avoid eutrophication. One option is to move from traditional sewage farming to an automated system that uses computers to filter and manage water and food resources more efficiently. A recent study on the optimal fish-to-mussel ratio in pearl ponds showed that more research is needed there, too.

The new regulations are forcing the industry to upgrade its techniques to produce pearls in a more ecologically sustainable manner. Although pearl farmers are having a difficult time at present, the changes may ultimately lead to sustainable, better-quality pearls that fetch higher prices.

This is an original article by chinadialogue and has been published with their permission. It can be found on their website here.

Editor: David Paulk.

(Header image: Workers grade pearls at a sorting factory in Zhuji, Zhejiang province, Sept. 6, 2011. Liang Zhen/VCG)