The survival of the oyster

In Hong Kong, the Edges of Earth expedition team explores the important ecological role that oysters play. Beyond their culinary appeal, they provide a range of services to their habitats that are essential for environmental well-being.

Words by Andi Cross
Photographs by Adam Moore
Additional photograph by Nicolas Job

Oysters, primarily recognised as a culinary delicacy, are enjoyed globally in a variety of species. Each is identified by a unique flavour profile and texture, influenced by their specific growing environment or ‘merroir’. For example, Pacific oysters, popular in Asia and the West Coast of North America, are noted for their sweet, creamy taste. By contrast, the Atlantic coast’s Eastern oysters are larger and celebrated for their balanced brininess. Kumamoto oysters are smaller with a distinct sweet, nutty flavour, while European flat oysters, or Belons, are favoured for their intense, coppery taste. Each variety reflects the richness and diversity of the world’s aquatic ecosystems.

But there’s another role that oysters play, and it’s one that often goes unnoticed. A role that we were going to explore as part of our conscious travel on the Edges of Earth expeditionBeyond their culinary appeal, oysters are ecological powerhouses, providing a range of services to their habitats that are essential for environmental well-being. Oysters act as natural water filters, each capable of cleansing gallons of water daily by removing excess nutrients and toxins, leading to improved water clarity and quality. Oyster reefs provide habitats and breeding grounds for various marine species, further promoting biodiversity. 

Their role in shoreline protection is also significant, as oyster reefs act as natural barriers, mitigating the effects of erosion and storm surges. In essence, oysters are not just a delicacy but are pivotal contributors to the health and resilience of marine environments.

Invited to join an oyster survey in collaboration with The Explorers Club Hong Kong Chapter, Swire Institute of Marine Science of The University of Hong Kong (SWIMS), and The Nature Conservancy (TNC), we were on a collective mission to explore oysters beyond their culinary value, and delve deeper into their ecological importance. While Hong Kong isn’t typically considered a remote, unexplored region—like the other locations on our expedition trail—its waters conceal a rich, enigmatic history that had us intrigued. The prospect of participating in this survey piqued our interest, as we were eager to uncover what lies beneath Hong Kong’s surface and assess the potential ecological significance awaiting discovery.

Upon arrival, we met with Adam Janikowski, The Explorers Club Project Lead; Marine Thomas, TNC’s Conservation Program Manager and; Dr. Bayden Russell, SWIMS’s Associate Director. Together, along with a few other local dive teams, we set out to sea in some of the most perilous conditions we’d seen yet on expedition. Hong Kong was getting some of the heaviest rain in its documented history while we were onsite, making diving interesting, to say the least. 

Rain or shine, we set sail around the Pearl River Delta to dive for oyster samples, with our main focus being the waters around Lantau Island. These samples would then be analysed and the data obtained would be stored in a database to help catalog oyster distribution in this region. When we arrived, the team was just finishing up the final location chosen to be a part of this survey. That meant the first step of the process was complete, but there was still so much more work to be done. 

Marine explained that the aim of this project had two parts. First, they needed to highlight the importance of this critical ecosystem off the coast of this massive urban sprawl. Second, they would need to amplify the dire situation in hopes of inspiring next generation scientists, conservationists and activists to take action. 

In its preliminary findings, the team discovered that there are still small patches of oyster reef worth saving here. And considering how valuable these reefs are to the local ecosystem, perhaps they could be brought back in some respect, to their former glory. Although wildly degraded, there still was hope in the shallows. The hard part wasn’t identifying the reef potential, it was going to be getting people to take the necessary steps to save the reefs and shift perception regarding shellfish. 

In order to understand what was happening today, we had to take a step back in time to when the lime industry was booming in Hong Kong. During the 19th to mid-20th century, this industry thrived due to the abundant shellfish reefs, rich in calcium carbonate that was burnt to create lime. Lime was an integral material in construction, agriculture and various other applications, helping to rapidly develop the region. 

However, the extensive dredging activities to satisfy the demand for lime led to a significant degradation of these once-vibrant underwater ecosystems. Shellfish, especially oysters, play a pivotal role not only in the economy but also in maintaining the ecological balance of the region. But, this was not fully understood at the time, nor is it even fully understood now.

Today, our appreciation for oyster habitats is not nearly on the same level as our appreciation for oyster consumption. These two worlds need to be examined separately, as their histories are frankly disparate. Yes, oyster farming is a huge part of Hong Kong’s history and culture. But this practice is not linked to the shellfish reef we were studying on expedition. What we were exploring were habitat oysters that had been significantly depleted here, made evident by the poor water quality, causing limited to no visibility, and the lacking marine life in these waters.

Shellfish reefs have long been unprotected here, with limited science in place to help back up their value. Bayden talked about re-establishing the reef’s importance when it comes to safeguarding Hong Kong against the climate crisis, emphasising the reefs as natural barriers and biodiversity hubs. This narrative was well received by our team, as the city was experiencing the most aggressive rain in its documented history, making many of our dives nearly impossible to navigate. Even locals on the street couldn’t help but comment on the climate crisis impacting their backyard. The rain flooding the streets was simply that alarming. 

In between the chaotic rain, we joined Bayden and Marine in their quest for oysters, equipped with our dive gear. Each dive around Lantau Island revealed a diverse range of shellfish, affirming the existence of salvageable and restorable reef patches. The finds, significant amidst the shifting baseline, highlighted the latent potential of these waters and marked a significant discovery for the entire team.

The concept of shifting baseline refers to the gradual lowering of standards for environmental health, as each generation adapts to a depleted version of the natural world. This subtle acceptance of environmental decline often goes unnoticed. After all, how is one to say just how bad the oyster population has been decimated when they cannot firsthand see what it looked like in the 1800s? However, the research team, through meticulous documentation of oyster populations, was seeking to redefine a clear benchmark to evaluate the deterioration of these essential marine ecosystems effectively.

Bayden and Marine emphasised that their efforts are focused on the future. Their research isn’t just meant to show current ecosystem health, but is being crafted as a resource for those who will take up the mantle of restoration in the future. Every piece of data is acting as the foundation for ongoing, informed action to restore these ecosystems to their original state. 

Marine said, “It’s an attainable goal to restore Lantau Island’s reefs. We’re aiming to seed a legacy where the resilience of oysters ignites collective, informed and strategic conservation initiatives. We’re not just looking to conserve these ecosystems but to rejuvenate them to their full potential.”

In a conversation over breakfast with Adam, we delved into the pivotal issue of changing human behaviour to prioritise environmental conservation. We wondered what catalyst in particular was needed to ignite a palpable shift in future generations towards valuing and actively preserving ecosystems, like the shellfish reefs. Given oysters are not considered charismatic species, it’s hard to drive interest—but not impossible. 

The global pandemic certainly woke many of us up to the realities of our declining world and the threats that sit right on our doorsteps. But what will it take to get masses mobilised around planetary restoration?

What is it going to take for us to foster a deep, intrinsic connection between the ocean and our survival? This is what the research team is up against next.

Now that they’ve identified the potential for restoration in these waters, they have an extremely tall order coming up hot. Changing perception and then behaviour is one of the hardest aspects of the job, no matter what industry or field you are in. And when it comes to inspiring change around shellfish reefs, there’s a lot of work to be done to cement this in the minds of policy and decision makers as well as the general public. 

The shifting baselines pose an insidious threat, yet this team’s findings offer hope and direction. The oysters of Hong Kong are more than just silent inhabitants of the city’s submerged ecosystems, they are indicators of an urgent dialogue that must be considered and taken seriously. Each collected sample, every piece of data, is a ‘delicacy’. Not one for culinary consumption, but rather for informed collective ecological awakening.

Upon our departure, we knew this wouldn’t be the last time we crossed paths with this incredible team. As their work was only just getting started, we had our hearts set on returning to see how far they’ve come. We will be keeping up with the oyster project, sharing more positive progress from Hong Kong. 


Photographs by Adam Moore
Additional photograph by Nicolas Job

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