New Documentary Explores Hong Kong’s Forgotten Oyster Reefs and Their Role in Securing a Sustainable Future

HONG KONG, April 22, 2025 /PRNewswire/ — This Earth Day (April 22, 2025) marks the online launch of a groundbreaking documentary, City of Shells: Our Forgotten Oyster Reefs (香江遺礁), which sheds light on this lost marine habitat and the urgent efforts to restore it. Produced and directed by Mike Sakas, the film follows researchers, historical ecologists, and restoration scientists as they explore the vital role oyster reefs played in Hong Kong’s history and economy, highlighting why their restoration is crucial for the city’s environmental resilience and sustainability.

The Silent Disappearance of Oyster Reefs

Oyster reefs are one of the most endangered marine habitats on the planet, with over 85% lAost globally due to overharvesting, pollution, and urban development. Hong Kong is no exception—once home to extensive shellfish ecosystems, its reefs have been relentlessly dredged, mined for lime production, and buried under reclamation projects over the centuries.

Despite their critical role in cleaning water, providing habitats for marine life, and protecting coastlines from erosion, these ecosystems remain largely absent from marine conservation policies. Unlike coral reefs and mangroves, oyster reefs lack formal recognition and official protection. Without an increase in local conservation efforts, they risk complete disappearance in Hong Kong waters—along with the immense environmental benefits they provide.

“Even for well-known marine species, conservation is a challenge due to inadequate protection, weak enforcement, and coastal development. But for oyster reefs, the situation is even worse. Without any form of recognition, they are left out of conservation policies entirely. If this doesn’t change, these already degraded, vulnerable ecosystems will disappear completely—along with the vast benefits they provide for ocean health,” says Marine Thomas, Associate Director of Conservation, The Nature Conservancy Hong Kong (TNC), who is featured in the film.

Professor Bayden Russell, from the Swire Institute of Marine Science (SWIMS), The University of Hong Kong, says that society has forgotten the vast benefits that oyster reefs provide both nature and society.

“Oyster reefs are extraordinary! It’s globally recognised that they house amazing biodiversity of other species, they fuel productivity in marine ecosystems, and are powerhouses for filtering and cleaning coastal waters. But, sadly, oyster reefs across the Pearl River Delta were almost completely gone before living memory due to overharvesting and coastal development. Until we started looking deep into the history of the area, we didn’t even know that they existed here! Just think of all the benefits to the environment and human society that we’re missing – we need to get it back! We need restoration.” 

Inside the Documentary

City of Shells: Our Forgotten Oyster Reefs is the culmination of three years of filming, chronicling over seven years of ongoing research and conservation efforts to restore oyster reefs in Hong Kong and the Pearl River Delta. Through historical research and scientific exploration, the film reveals how oysters have shaped the region’s development — delving deeper into the socio-cultural ties between oysters and coastal communities, the lime industry that fueled early infrastructure across the region, and the thriving marine ecosystems that once flourished beneath its waters.

The film follows a team of researchers, restoration ecologists, citizen explorers, and marine scientists as they search for remnant reefs, using historical maps, ecological surveys, and underwater expeditions to piece together clues about where these lost habitats might still perdure. Their findings suggest that not all is lost, and if restoration efforts are implemented at scale, oyster reefs could flourish once more. And the prospect is enormous—by filtering millions of liters of water daily, providing essential habitats for marine species, and acting as natural coastal barriers against storms and erosion, these restored ecosystems would significantly enhance biodiversity and ocean health, bringing life back to our waters.

“Conservation is a rather young concept, and its genesis lies in a reaction to the observed loss of habitat. So, when we think about conservation, we tend to approach it with the intent of minimizing damage, and we rarely think about conservation as an opportunity for enhancing benefits. Restoration is an opportunity to enrich our environment and improve the health of systems in the region, with knock-on benefits to everyone who lives and works in the Pearl River Delta,” says Mike Sakas, producer and director of the film. “Oyster reefs fulfilled a fundamental role in both Hong Kong’s marine landscape and the city’s evolution, and yet today, they are virtually forgotten.”

“This film is not just about oysters—it is about rebalancing our relationship with the ocean,” Sakas continues. “Environmental restoration and human progress can coexist; they must coexist. We got here because of a rich environment, why would we think we could go forward without it? The good news is, in the case of our oyster reefs anyway, if we give them a chance, they have the potential to regenerate. With a nudge from us and a bit of care, these little creatures can get on with the work of restoring balance to marine environments and strengthening coastlines.”

But Sakas warns that action must be taken soon. “We are approaching the deadline for action. Without immediate restoration efforts, these ecosystems—and their immense environmental benefits—could be lost forever. Oysters certainly aren’t going to win mass adoption based on looks. But if we want to swim in clean water, take our kids fishing, and see more wildlife along the shores, then we need to get down to the business of caring for oysters. If we do, the natural features we love about Hong Kong will be even more magnificent. If we don’t, it will be our loss and our failure to future generations.”

TNC is honored to be featured in the documentary, contributing its expertise in marine conservation and restoration. Through its ongoing efforts, TNC strives to protect and restore oyster reefs as part of a broader mission to safeguard Hong Kong’s marine ecosystems for future generations.

The Asia premiere of City of Shells: Our Forgotten Oyster Reefs took place in Hong Kong on April 14, aiming to raise public awareness and increase support for oyster reefs as the Hong Kong government updates its Biodiversity Strategy Action Plan (BSAP) later this year. It was a wonderful evening celebrating the importance of oyster reefs.

In addition to the premiere, TNC, in collaboration with other featured organizations, including The Swire Institute of Marine Science (SWIMS) of The University of Hong Kong, and The Explorers Club HK, will host private screenings and public talks featuring the film’s scientists and conservationists. These events will provide insights into the ecological significance of oysters and discuss actionable solutions for protecting these vital habitats.

The full documentary is now available to the public online at www.cityofshells.com, inviting viewers in Hong Kong to learn more and take part in raising awareness for marine restoration.

This documentary was made possible through the support of Hermès Asia Pacific Limited and the dedicated efforts of numerous organizations, including The Nature Conservancy Hong Kong Foundation Limited, The Swire Institute of Marine Science, The University of Hong Kong, The Explorers Club Hong Kong, Streamline Media / TNC Australia, Airport Authority Hong Kong, Dr. Boze Hancock, Prof. Daniel Pauly, Deep Bay Oyster Cultivation Association, Edges Of Earth, Hong Kong Oyster Hatchery and Innovation Research Unit, Marine Ecology Enhancement Fund, Marine Futures Laboratory, Shelly McLeod, Charlie and Rex, Simon F.S. Li Marine Science Laboratory, The Chinese University of Hong Kong, South China Diving Club, Way Foong Charters, William Meacham, and William Sargent. Their collective contributions to research, restoration, and education continue to drive meaningful change in the conservation of oyster reefs.

For more information about the documentary or to learn how to support oyster reef restoration, visit www.cityofshells.com.

About Director Mike Sakas

Mike Sakas is a professional photographer and documentary maker who has devoted his career to documenting projects of social and environmental significance. His passion for adventure, conservation, and an insatiable curiosity underpins the narrative of City of Shells: our Forgotten Oyster Reefs and highlights the pressing issues facing our oyster reefs.

About The Nature Conservancy Hong Kong (TNC)

The Nature Conservancy (TNC) is the world’s leading international conservation non-profit organization dedicated to protecting natural places and preserving life on Earth for future generations since 1951. TNC follows a science-based conservation approach to create innovative solutions to global conservation challenges and enable nature and people to thrive together. We are currently addressing climate change at an unprecedented scale by protecting lands, waters, and oceans in sustainable ways, providing food and water resources, and helping cities become more sustainable.  Our projects span 81 countries and territories, using collaborative approaches with local communities, governments, private sector and others, to carry out various conservation projects and activities, including biodiversity conservation, forest conservation, marine conservation, climate change, and sustainable land use. TNC organizes various community projects and educational activities, aiming to promote public awareness and action towards environmental protection and sustainable development and to raise public awareness of natural environments and wildlife. TNC has been in Asia Pacific for almost 30 years with projects in Australia, China, Hong Kong (SAR), Indonesia, Mongolia, New Zealand, and the Pacific Islands. TNC was awarded the 2019 Lui Che Woo Prize – Prize for Sustainable Development. For more about TNC’s work, please visit: The Nature Conservancy (tnc.org.hk)

If you also care about environmental protection and wildlife conservation, please support TNC’s work, participate in our community projects and activities, and work together to protect the natural environment and wildlife, follow TNC Hong Kong’s social platforms for more environmental conservation information:

Facebook: TNC HK 大自然保護協會
Instagram: @tnc_hk 

About The Explorers Club Hong Kong

The Explorers Club is an international multidisciplinary professional society dedicated to the advancement of field research and the ideal that it is vital to preserve the instinct to explore. Since its inception in 1904, the Club has served as a meeting point and unifying force for explorers and scientists worldwide, and its members have been responsible for an illustrious series of famous firsts, including first to the North Pole, first to the South Pole, first to the summit of Mount Everest, first to the deepest point in the ocean, and first to the surface of the moon. The Explorers Club Hong Kong Chapter was established in 2013 to expand the Club’s mission in Asia, and to create a modern base of operations for staging more inclusive and innovating scientific expeditions in the region and beyond. Today the HK Chapter is home to over 60 of Hong Kong’s most intrepid explorers, conservationists and hardcore field scientists as well as Explorers Club members from all over the world who are drawn to its unique “Collaboration over Conquest” approach to exploration.

About The Swire Institute of Marine Science (The University of Hong Kong)

The Swire Institute of Marine Science (SWIMS) is one of the world’s leading marine research institutions. The research of SWIMS’ scientists is focused on the interaction of humanity and the ocean – SWIMS specialises in the study of coastal ecosystems, the shallow seas that hundreds of millions of people depend on for their livelihood. Using leading technology and novel, interdisciplinary methods, SWIMS studies the impact of human actions, such as climate change and pollution, on marine ecosystems and biodiversity, providing science-based solutions to conservation, restoration, and sustainable management of marine resources. Hong Kong’s maritime traditions and marine biodiversity are SWIMS’ local roots, but the impact is global. Since its foundation in 1990, SWIMS has trained hundreds of scientists from over 30 countries, who have gone on to play leading roles in marine research and conservation.

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SOURCE The Nature Conservancy