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Oysters become a lifeline in the face of rising sea levels

An unlikely ecological saviour, one mollusc has the potential to help save us from rising seas – but only if we work at reforesting them in places where they once thrived.

One odd but delectable brunch-time staple is now viewed as a key tool of defence against the effects of climate change.

That’s right – oysters, with their rock-like shells and cluster-growing formations, could be essential in protecting coastal towns and cities.

That being said, 85% of the world’s oyster colonies have disappeared in the last century as a result of harvesting, pollution, and disease. As with most environmental revelations, we’ve only recently come to acknowledge their important role for life in the sea and onshore.

In addition to providing a habitat for small invertebrate and other larger fish to live, oysters provide the essential service of improving water quality by filtering harmful toxins from the surrounding ocean. Just one of these little creatures can filter over fifty gallons of water a day.

To human benefit, bunches of oysters are living barriers that protect shorelines from flooding and erosion during storm surges. They also act as breakwaters in the face of large waves, protecting communities on land in a similar way that mangroves and coral reefs do.

Many vulnerable regions have already come up with practical solutions for these events, such as man-made dykes and concrete embankments.

However, with 250 million people currently vulnerable to flooding impacts globally – and that number expected to double by 2100 – fostering naturally regenerative, climate-protective solutions has become an increasingly attractive option.

Of course, there are necessary conditions oysters need to survive. Appropriate water temperature, sea current velocity, pH levels, salinity, and dissolved oxygen are all features that will keep oysters happy.

When this environment is available, ecological engineering can take place. Then voilà! We have an oyster-led sustainable ecosystem that is designed for both natural and human benefit.

Basically, if we help to restore populations to a level before we interfered, nature will take care of the rest – and who doesn’t want that?

The Billion Oyster Project has been working to reforest The New York Harbour, which was previously home to 220,00 acres of oyster reefs.

At one point, the city was so abundant with them that they were sold cheaply from carts on the side of the road like hot dogs are today. That was before dredging, pollution, and over-farming occurred in the harbour’s waters, hence their disappearance.

The Billionaire Oyster Project was born out of the pandemic, when live oysters were going to waste while restaurants were closed. Now, empty shells are collected from local eateries, cleaned, transferred into biodegradable mesh bags, and placed back onto the seabed to provide a structural habitat for new oysters to grow.

New York has been particularly targeted by flooding this year, only emphasising the necessity for immediate action in terms of protecting residents from changes in weather patterns. Recent efforts to rehabilitate oyster populations around its shores could be beneficial in reducing such events.

Around the world, similar projects are taking place, particularly in the Gulf of Mexico and around an island near Bangladesh, which have both experienced serious erosion and forced migration of coastal communities due to rising sea levels.

New oyster reefs in the distance provide a glimmer of hope for people looking out from deteriorating coastal shores. However, relying on them alone would be a mistake.

These alien-looking molluscs will play their role – but we’ll need to do our part by getting a grip on the current climate, too.