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When most people think of rising sea levels, they’re imagining the possible disappearance of South Pacific islands or the Netherlands. But sea level rise is a reality around the world. Canada is no different. Even in 2021, Vancouver's famous sea wall failed due to storm surges and the infamous beaching of a barge left that on shore for many months. Clearly, our current approach is not enough to protect shorelines as seas rise and the force of waves increases.
We need to turn to nature for inspiration on how to address these issues as this threatens ecosystems and communities alike. When you think of a sea wall or a breakwater, it’s usually a long concrete structure that exists on the shoreline. But what if this was not the only option? What if we were able to cultivate natural habitats on our shores that could help protect us from rising seas and storm surges.
Oysters have grown in British Columbia for as long as humans have been here. The native species is Olympia oysters, which were historically harvested and eaten by Indigenous people. Their shells were also important for some Nations for cultural reasons, though scallop shells were often more prized.
After colonization, Pacific oysters from Japan were brought over to be cultivated. Pacific oysters are larger, faster growing, and more resilient than Olympias, known colloquially as "Olys". Though the introduction of Pacifics led to a boom in oyster cultivation and farms in BC, it also led to them becoming invasive. Today, Pacifics are the predominant oyster species in BC waters. Olympia oysters are still present, but not in the same numbers as the past.
Oysters have always been important to the people on the Pacific coast for the ability of their communities to thrive. They contributed to food systems, economies, cultures, healthy ecosystems, clean water, and food security. While oysters are not endangered in BC, they no longer receive the same reverence or respect they once did outside of when they are being enjoyed on a plate (which is still a great way to enjoy them!).
By building oyster reefs, SURGE is working to contribute to a renewed understanding and relationship with oysters due to their many benefits. Constructing these oyster reefs as living breakwaters will help to protect the places where communities have existed in various forms for thousands of years. This same protection they provide to communities will extend to key coastal ecosystems like eelgrass meadows and coastal salt marshes.
Eelgrass meadows are immensely important ecosystems. Eelgrass is a type of seagrass, which is a group of about 60 species that are the only marine flowering plants. Eelgrass is widely distributed around the world but is threatened due to coastal erosion, and green shorelines being traded in for engineered coastal defences. In British Columbia, they act as important habitats for predators and prey who use them to hide from each other.
They act as the spawning grounds for Pacific herring, which is a crucial local fishery. Pacific herring have always been important to the First Nations on the Pacific Coast and continues to be a commercially vital, but highly threatened fishery today. The eggs the herring lay on eelgrass is also a traditional delicacy. The eelgrass blades would be harvested with the eggs on them that are eaten right off the plant.
Eelgrass meadows also help to reduce wave force on shorelines, helping to reduce the amount of erosion activity, but they can only do so much on their own. Being threatened and disappearing only makes it harder for them to provide that benefit as well.
Coastal salt marshes are unique ecosystems that exist on the shore and thrive off of the tides depositing salt water in them. Along with this salt water, sediment is also deposited, which helps extend the shore into the water, which in balance with the natural rate of erosion, ensures ecosystems and shorelines exist in equilibrium. Climate change has disrupted this equilibrium and this sediment deposit is no longer enough. Salt marshes tend to have unique and diverse organisms not found elsewhere. They exist in a very thin band geographically between land and sea. They act as a green wall between tides, erosion, storm surges, and flooding between the ocean and human populations. As these disappear due to encroaching sea levels and development on either side, they are quite threatened.
This also presents a very difficult situation as coastal salt marshes are one of the best carbon sinks in the world and as they disappear the carbon trapped in them will be released into the atmosphere and the sequestering services they currently provide will disappear.
Due to how crucial these ecosystems are and how living breakwaters can help protect them, building oyster reefs also help protect Earth's precious biodiversity and acts as a form of climate action. SURGE's oyster reefs will also contribute to providing habitat and a food source for many organisms in the waters where they reside, thus leading to increased biodiversity and more thriving ecosystems in the water.
Building oyster reefs is crucial for the ecological and cultural heritage of British Columbia. They have almost too many benefits to count and are much cheaper than the existing strategies being used that are not enough on their own. It only makes sense that we need to be getting them in our waters as soon as possible!