Hong Kong Oyster Hatchery and Innovation Research Unit (HKO-HIRU)
The University of Hong Kong
The need for an oyster hatchery in Hong Kong
Towards a sustainable and profitable aquaculture practice for cultural inheritance
Oyster farming: Hong Kong's intangible cultural heritage
Oyster cultivation around the Pearl River Estuary has more than 700 years of history. In Hong Kong, most of the activities take place in the Deep Bay area of Lau Fau Shan, the northwestern corner of the city.
Traditionally, oysters are farmed by the bottom culture method. Growers lay concrete tiles, rocks or cement columns on the intertidal mudflats to collect wild oyster seeds from May to June every year. The spats usually take 3-5 years to reach marketable size.
Since the 1980s, oyster farming has been gradually adopted to raft culture method. Spats are attached on the strings with cement substrates or placed in baskets and suspended from floating bamboo rafts. In recent years, local growers also import medium-sized spats from China for fattening purpose, so that the time required to reach the market can be shortened.
Indispensable oyster production in China and Hong Kong
Changes in global and China's oyster production over 2003–2022
Production of sun-dried golden oysters
China is the leading country for oyster production in terms of mass, accounting for more than 87% of the world's total supply. Not just confined in Deep Bay, the Hong Kong oyster (Magallana hongkongensis), also know as the "white oyster", is farmed extensively along the coastlines of southern China. This single species plays a major economic role in the region, contributing a quarter of the country's total oyster output with an annual volume reaching approximately 1.9 million tons in 2024. In Hong Kong, the annual oyster production has remained at around 100 tons (meat only) with output value above HKD 10 million over the past decade.
Apart from their ecological values like improving water quality and oyster reef's ability to restore coastal biodiversity, oysters are considered as an essential nutrient-rich carbon-neutral seafood delicacy. Hong Kong oysters are sold in fresh or more often in semi-dried form known as "sun-dried golden oysters", a popular commodity during Lunar New Year symbolizing prosperity in Cantonese culture.
Challenges for the local oyster industry
Yet despite its cultural, economic, and ecological importance, local growers are facing enormous pressures from various aspects:
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Climate change: Environmental fluctuations, more frequent natural disasters (e.g. super typhoon, extreme rainfall and heatwaves) and recurring mass mortality events severely disrupt the harvest cycles, and consequently reduce the production amount and values of oyster meat.
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Insufficient seed supply with uncertain quality: Large demand for oyster seeds cannot be met by current oyster cultivation technology in Hong Kong and southern China. While wild seed recruitment has been declining over the past 20 years, most of the local growers are now purchasing seeds from outside Hong Kong. However, there are huge uncertainties regarding the seed quality, genetic performance and environmental adaptation, hindering the sustainability of the entire industry.
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Lack of coastal management strategies: Factors such as reclamation, habitat destruction and increasing culture density contribute to the elevated stress on oysters. Eventually, the areas are no longer suitable for producing healthy oysters.
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Labour-intensive aquaculture practice: Traditional oyster cultivation practices rely solely on muscle power - all procedures from seed collection to marketing are done manually. Nevertheless, growers are reluctant to adopt modern aquaculture technologies as they are familiar with the current practice and feeling not cost-effective to upgrade just for their cottage business. Gradually, oyster farming in Hong Kong is labelled as a "sunset industry" and more difficult to attract younger generations to enter the business.
Having an oyster hatchery in Hong Kong is an economically stable and sustainable option to solve the problem. In the hatchery, we can control the environmental conditions to ensure maximum seed production. Sustainable oyster production in Hong Kong (and in South China in general) is a pressing issue for indigenous oyster growers, local government, and politicians. Transferring these experiences to them will ensure the sustainability and is vital for seafood security in the future world.
Price per unit weight (USD) of aquaculture oysters for top producing countries. The price of oysters produced from China was among the highest in 1980s, but now the price has gone down due to increasing supply but reducing quality.
Traditional labour-intensive oyster aquaculture practice