Hong Kong has a long history as a centre of pearl farming, with Tai Po once considered a source of some of the finest pearls in China. But over the past century, pearl farming has fallen by the wayside. The SinoJapanese war disrupted activity, then post-war Japanese monopolies hampered the pearl industry, which was also damaged by a series of severe typhoons in the 1960s. It ultimately became unprofitable for local fishermen to harvest pearls. To Dr Yan Wa-tat, this represented a wasted resource. As a former financier with a deep interest in the marine environment, he decided to do something about that. In 2015, he enrolled in a PhD programme at HKU, focussing his research on reviving the local pearl industry. This has led to a partnership with Professor Billy Chow Kwok-chong, Chair Professor of Endocrinology in the School of Biological Sciences, and the establishment of the Pearl Power Research Institute (PPRI). “Hong Kong has more than 1,000 fish farming rafts and 90 per cent are not productive because the fishermen find it not profitable to farm fish. I thought, why not try to use these idle fish farms for pearl oyster farming?” Dr Yan said. He reached out to fishermen to join his research and, initially, hoped to train them in seeding oysters to produce pearls. But this process requires speed and training and, since most of the fishermen were in their 50s or older, he began thinking of a different approach – focussing on the oyster shells instead of pearls. Oyster shells are a component in traditional Chinese medicine to treat such things as anti-inflammation, detoxification and anti-ageing. He then got an opportunity to pitch the and other minerals. Using a local species, the Pinctada fucata, the team ground the shells into a pearl powder of different combinations and confirmed its effectiveness in detoxifying heavy metal concentrations in mice. They have also confirmed its effectiveness as an antioxidant and in boosting gut health. Under Professor Chow’s guidance, the team have received research funding from the Fisheries Enhancement Fund of the Airport Authority, secured three patents and IP rights and launched the PPRI, a start-up company that has received support from HKU’s SEED and iDendron programmes and the Hong Kong Science and Technology Park’s Ideation Programme. “We hope to use our technology to develop locally produced pearl powder for the benefit of people in But medicinal products are not the only benefit to be reaped from oyster shells. They can also be used to reduce greenhouse gases. Most shellfish are made up of about 40 per cent carbon dioxide, which they have captured and stored from the environment. The team established that these benefits can be achieved in Hong Kong. They set up another start-up, BivaCoo Limited, last year to explore the possibility of using local oyster farms in carbon offset projects. There are already examples of this in the Chinese Mainland, such as the city of Weihai in Shandong province. BivaCoo has already graduated from the Ideation Programme and is working with local fishermen to develop the venture further. “It’s a nature-based solution,” Dr Yan said. “We want to get these ideas out in society and not just hide them away on campus.” Dr Yan noted that it was easier and cheaper for fishermen to use fish rafts to farm oysters rather than fish because oysters are filter feeders and do not require feed. They also produce a harvest more quickly. He also sees potential in developing the rafts as centres for tourism and education. “I hope PPRI can be financially sustainable within the next two or three years,” he said. Catching carbon Hong Kong and the Chinese Mainland,” Professor Chow said. Supplements have been developed and will soon be distributed through PPRI. Importantly, local fishermen are shareholders in the venture. “One day, I met him in the elevator, and he asked about my research. I told him that while I was going to finish my thesis, I was afraid local fishermen could not benefit because it would take years for them to learn how to produce pearls. Then I asked him if he would be interested in doing some research on pearl powder, and he said, why not? That was my elevator pitch!” Dr Yan said. The pair began investigating the properties and applications of oyster shells. The shells, particularly the mother-of-pearl, or nacre, that lines the shells, contain protein, amino acids, calcium carbonate, magnesium Elevator pitch idea of using the shells to Professor Chow, who, among other things, was working on translational research in drug discovery. Dr Yan Wa-tat (right) at an oyster raft. Pearls of Wisdom Oysters have many benefits beyond producing pearls and succulent flesh. As scientists at HKU have confirmed, they can have positive health and environmental effects and farming them could boost the flagging fortunes of local fishermen. HKU Bulletin | Nov 2025 Knowledge Exchange 34 35 It’s a nature-based solution. We want to get these ideas out in society and not just hide them away on campus. Dr Yan Wa-tat
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